This document provides an overview of chemical reactions and energetics for a 10th grade IGCSE course. It discusses exothermic and endothermic reactions in relation to energy changes and temperature. It also covers the factors that affect reaction rates, including concentration, particle size, catalysis, and temperature. The document defines oxidation and reduction in terms of electron transfer and identifies redox reactions. It provides examples of exothermic and endothermic reactions and discusses how catalysts can lower the activation energy and increase reaction rates. Interactive links are included to illustrate and reinforce the concepts.
This document provides information on tests for ions and gases from a chemistry course. It describes flame tests to identify Li+, Na+, K+, and Ca2+ cations, and tests using sodium hydroxide solution to detect NH4+ or produce precipitates of metal hydroxides to identify Cu2+, Fe2+, and Fe3+ cations. Anions can be identified by precipitates formed with silver nitrate and nitric acid for Cl-, Br-, or I-, barium chloride for SO42-, or by detecting carbon dioxide gas evolved from reaction with hydrochloric acid for CO32-. Common cations and anions are also listed.
The document discusses the chemical properties of alkali metals. It explains that alkali metals react vigorously with oxygen and water. The reactivity increases down the group as the atoms get larger, shielding the outer electrons from the nucleus and making them easier to lose. Equations for reactions of lithium, sodium, and potassium with oxygen, water, and other substances are provided. Flame tests for group 2 metals are also discussed.
This document is about atoms, elements, and chemical reactions. It contains three main sections: (1) what atoms and elements are, including their symbols and arrangement in the periodic table, (2) how elements can combine to form compounds with different properties, and (3) how chemical reactions allow atoms to join together to form new substances.
The document is a lesson on compounds and mixtures. It discusses the differences between elements, compounds and mixtures. Compounds are formed by chemical reactions between elements and have fixed compositions shown by chemical formulas. Mixtures can be separated into their original substances as they are not chemically bonded. Various methods for separating mixtures are described such as filtration, evaporation and distillation.
Organic chemistry revision notes cover the formation of fossil fuels like oil from dead marine organisms under heat and pressure. Crude oil is separated into fractions like gasoline and kerosene through fractional distillation, and combustion produces pollution like carbon monoxide and nitrogen oxides. The energy released during combustion can be measured using a calorimeter. Homologous series are families of compounds with the same functional group and general formula that differ by CH2. Main series include alkanes, alkenes, and alcohols, which are named based on their carbon chain and functional group.
Atoms, elements, compounds and mixtures.pptxSoniaTaneja15
1) The document discusses atoms, elements, compounds, and mixtures. It aims to explain what an atom is, differentiate between elements, compounds and mixtures, and give examples of each.
2) Atoms are the basic building blocks of all matter and are very small. Elements are substances made of only one type of atom that cannot be broken down further.
3) Compounds are formed when two or more elements are chemically bonded together and have different properties than the original elements. Mixtures contain two or more substances that are not chemically bonded and can be separated.
Thermochemistry is the study of heat changes in chemical reactions and phase changes. There are two types of energy - kinetic energy, which is the energy of motion, and potential energy, which is stored energy like that in chemical bonds. Energy cannot be created or destroyed, only converted between kinetic and potential forms. Heat is a transfer of energy between objects due to a temperature difference, flowing from warmer to cooler until equal temperatures are reached. Exothermic reactions release heat while endothermic reactions absorb heat from their surroundings.
This document provides an introduction to acids, bases, and salts for GCSE chemistry students. It discusses key topics like acidity and alkalinity, indicators, the pH scale, types of acids including strong and weak acids, and various methods for making salts through reactions between acids and metals, metal oxides, metal carbonates, metal hydroxides, and ammonia. The document is intended to help students understand and revise these core chemistry concepts in preparation for their exams.
Rate of reaction is defined as the change in quantity of reactants or products per unit time. The average rate is calculated over an interval of time, while the instantaneous rate is the actual rate at a given time. Several factors affect the rate of reaction, including the total surface area and concentration of reactants, temperature, use of catalysts, and pressure for gaseous reactants. According to collision theory, the rate of reaction depends on the frequency and effectiveness of collisions between reactant particles, which must achieve the minimum activation energy and correct orientation.
The document discusses the reactivity of metals, displacement reactions, and reactions of metals with acids and water. It explains that more reactive metals, like potassium, lose electrons more easily and form positive ions. Less reactive metals, like copper, have more valence electrons and are harder to oxidize. A displacement reaction occurs when one reactant replaces part of another. Single displacement reactions involve one reactant replacing part of the other, while double displacement reactions involve parts of two reactants being exchanged. The reactivity series can predict how vigorously a metal will react with acids based on its position on the series.
This document discusses reactivity of metals and minerals. It begins by describing the different types of minerals found in rocks and ores, including natural elements like gold and compounds like limestone. It then explains how the reactivity of metals can be determined by observing their reactions with oxygen and other substances. Experiments are described to determine the position of carbon and hydrogen in the reactivity series by observing whether they can displace metals from metal oxides when heated. The document concludes that understanding the reactivity series is important for extracting metals from their ores.
Reactions Of Metals And Metal Compoundsamr hassaan
The document discusses chemical reactions involving metals and their compounds. It explains that metals react with acids to produce salts and hydrogen gas. It also discusses how metals react with oxygen and carbon dioxide to form metal oxides and metal carbonates, which can then further react with acids. The document provides examples of word equations for common metal-acid reactions and identifies the products and reactants in various chemical changes involving metals and their compounds.
The document provides information about grade 10 IGCSE chemistry content related to properties and reactions of metals. It discusses distinguishing metals from non-metals, reactivity series, extraction of metals like iron from ores, and uses of metals such as aluminum and zinc. It also describes physical and chemical properties of metals, structure and properties of alloys, and reactions of metals with water, steam, and acids to determine reactivity order.
This document outlines the 5 main types of chemical reactions:
1) Synthesis reactions involve combining two or more substances to form a single product.
2) Decomposition reactions involve a single reactant breaking down into multiple products.
3) Single replacement reactions involve one element replacing another in a compound.
4) Double replacement reactions involve ion exchange between two compounds in solution.
5) Combustion reactions involve oxidation, producing energy, carbon dioxide, and water when oxygen reacts with a fuel.
The document discusses the properties and reactivity of metals. It describes experiments to determine the reactivity series of metals by observing their reactions with water, steam, and dilute acids. Metals react differently in each test based on their positions in the reactivity series, from most reactive to least reactive. The reactivity series allows prediction of other reactions like reduction of metal oxides and decomposition of metal carbonates.
The document discusses the reactivity series of metals and how it is determined. The reactivity of a metal is based on its tendency to lose electrons and form positive ions. Experiments are conducted to see which metals react with water, acids, carbon, other metals, and metal ion solutions. These experiments allow metals to be ranked in a reactivity series from most reactive to least reactive. The reactivity series can then be used to predict and understand redox reactions between metals.
This is a summary of the topic "Energy changes" in the GCE O levels subject: Chemistry. Students taking either the combined science (chemistry/physics) or pure chemistry will find this useful. These slides are prepared according to the learning outcomes required by the examinations board.
This document discusses the reactions of various metals with water, steam, and heat. Some reactive metals like sodium and potassium react vigorously with cold water, producing metal hydroxides and hydrogen gas. The reaction of potassium with cold water produces a colorless solution and burns with a lilac color. Calcium also reacts with cold water but does not ignite the hydrogen produced. Magnesium reacts with hot water but not cold water. Less reactive metals like aluminum, iron and zinc only react with steam, producing metal oxides and hydrogen gas. Some metals like lead, copper, silver and gold do not react at all with water, steam or heat.
This document discusses the preparation and classification of salts. Salts are formed through the replacement of hydrogen ions in acids by metal ions or ammonium ions. There are two main methods for preparing salts - neutralization and precipitation. Neutralization involves reacting an acid with a metal, alkali, oxide or carbonate to form a soluble salt. Precipitation involves mixing two aqueous solutions of soluble salts to form an insoluble salt precipitate. The document provides examples of preparing various salts such as potassium chloride and lead chloride. It also discusses classifying salts as soluble or insoluble and purifying soluble salts through recrystallization.
The document discusses identification of ions and gases in chemistry. It describes various tests that can be used to identify metal cations, anions, and gases. Tests to identify metal cations include observing the color of precipitates formed with sodium hydroxide and ammonium solutions, as well as observing the color of flames in flame tests. Tests to identify anions include observing color changes with solutions. Tests to identify gases include observing physical and chemical properties. The document also provides examples of past exam questions related to identifying ions.
This is an example of a combustion reaction. Propane (C3H8) is burning in oxygen gas (O2), producing carbon dioxide (CO2) and water vapor (H2O) as products. The balanced chemical equation is:
C3H8 + 5O2 → 3CO2 + 4H2O
Rate of reaction chemical kinetics (condensed)jslayer
The document discusses the factors that affect the rate of chemical reactions, including temperature, concentration, pressure, surface area, and the use of catalysts. It explains that reactions occur via particle collisions and that these factors influence the collision rate. For example, higher temperatures increase particle energy and collision frequency, while catalysts reduce the activation energy needed for reactions to occur. The document also provides examples of catalysts used in industrial processes and enzymes that catalyze biological reactions.
The document discusses the noble gases and their uses such as helium for balloons, neon for signs, and argon in light bulbs. It then covers the halogens, their characteristics of being nonmetals, reactive, existing as diatomic molecules, and having 7 valence electrons. Tables show the halogens' states, boiling points, melting points, colors from pale yellow fluorine to shiny black iodine, with reactivity increasing down the group.
The document lists examples of transition elements such as copper, iron, tungsten, and scandium. It also mentions that transition elements such as iron, platinum, nickel, and vanadium oxide are used as catalysts in various industrial processes like the Haber process, Ostwald process, margarine production, and the Contact process.
Acids, Bases and Salts (Chemistry 'O' level)Faiz Abdullah
Chemistry 'O' level syllabus: Acids, Bases & Salts
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The periodic table and identification of ionsCarole Paquette
The document summarizes key concepts about the periodic table, identification of ions and gases. It describes trends in properties for groups I and VII, such as how reactivity increases down group I due to electron shielding. Tests are outlined to identify aqueous cations, anions and common gases. Uses of transition metals and noble gases are briefly mentioned.
The document is about acids and alkalis and their reactions. It discusses how acids and alkalis react to form salts and water through a neutralization reaction. It provides examples of reactions between acids and bases like metals, metal oxides, and carbonates. The document also covers acid rain, how it is formed from air pollution, and its environmental effects. It describes methods to reduce acid rain by limiting the emissions of sulfur dioxide and nitrogen oxides.
Chemical energy is energy stored in the bonds of chemical compounds. This energy is released when a chemical reaction takes place, transforming the original substances into new ones. Exothermic reactions release thermal energy (heat) into their surroundings, causing the temperature to increase. Examples include combustion and neutralization reactions. Endothermic reactions absorb energy from their surroundings.
The document discusses exothermic reactions and how some can be hazardous. It provides data on the enthalpy changes (ΔH) for the reactions of rusting and hydrogen explosions. The document then discusses reaction rates, how they are measured, and factors that influence them such as temperature, concentration, particle size, and the use of catalysts. According to collision theory, reactions occur when particles collide with sufficient kinetic energy to overcome the activation energy barrier. [END SUMMARY]
1. The document discusses factors that affect the rate of chemical reactions, including surface area, concentration, pressure, temperature, and catalysis.
2. Catalysts work by lowering the activation energy of reactions, increasing the proportion of particles with energy exceeding this barrier.
3. Enzymes are biological catalysts that are highly specific and function via a lock-and-key mechanism to catalyze reactions in living organisms.
The document discusses acids, bases, and pH. It defines acids as having a pH below 7, bases as above 7, and neutral substances as having a pH of 7. pH is measured using indicators like universal indicator or litmus paper. Acids react with metals to produce hydrogen gas and salts, with bases to produce water and salts, and with carbonates to produce water, carbon dioxide and salts. Controlling acidity in the environment is important for plant growth and ecosystems.
Lecture 2 By MUHAMMAD FAHAD ANSARI 12 IEEM 14fahadansari131
This document summarizes the key points about types of chemical reactions and factors that affect reaction rates. It discusses the 5 main types of chemical reactions: synthesis, decomposition, single-replacement, double-replacement, and oxidation-reduction. It also outlines characteristics of each type and provides examples. Additionally, the document covers concepts like activation energy, catalysts, temperature effects, and concentration effects on reaction rates. Finally, it briefly discusses chemical equilibrium and kinetic molecular theory of gases.
The document discusses several factors that can affect the rate of a chemical reaction:
1) Surface area - Increasing the surface area of a solid reactant increases the reaction rate by providing more collision sites.
2) Concentration - Increasing the concentration of a reactant increases the number of collisions between reacting particles and thus increases the reaction rate.
3) Temperature - Raising the temperature increases the kinetic energy of reacting particles, allowing more collisions with sufficient energy to result in reaction. This generally causes reaction rates to increase exponentially with temperature increases.
4) Catalysts - Catalysts provide an alternative reaction pathway requiring lower activation energy, allowing more collisions to result in reaction. This increases the reaction
(1) Collision theory states that for a chemical reaction to occur, reactant molecules must collide with sufficient kinetic energy and in the correct orientation. (2) Increasing temperature increases the average kinetic energy of particles and the number of collisions, thereby increasing the probability that reactants will overcome the activation energy barrier. (3) Factors like concentration, surface area, and use of a catalyst can also increase the reaction rate by elevating the frequency of successful collisions between reactants.
The document discusses kinetics and reaction rates. It defines kinetics as the branch of chemistry that studies the speed or rate of chemical reactions. It explains that reaction rates can be measured by changes in concentration, temperature, or pressure over time. The rate depends on factors like the nature of reactants, concentration, temperature, catalysts, surface area, and pressure. Reactions may occur in multiple steps through reaction intermediates rather than a single step. The collision theory and concept of activation energy are introduced to explain why certain collisions result in reactions. Reaction coordinate diagrams are used to illustrate the energy changes in reactions.
This document discusses chemical equations and balancing chemical reactions. It explains that a chemical equation describes a chemical change and is made up of reactants on the left and products on the right, with coefficients showing quantities. Balancing equations involves adjusting these coefficients to satisfy the law of conservation of mass, ensuring the same number and type of atoms enter and leave the reaction. Several examples of balancing equations are provided.
CHEMICAL REACTION
CHEMICAL EQUATION
CHEMICAL FORMULA
BALANCING
TYPES OF CHEMICAL REACTION
COLLISION THEORY
FACTORS AFFECTING THE RATE OF CHEMICAL REACTION
This chapter discusses the rate of reaction and factors that affect it, including:
1) The size of reactants - smaller particles have a larger surface area and thus react faster.
2) Concentration of reactants - higher concentrations lead to more collisions and a faster rate.
3) Temperature - raising the temperature increases molecular motion and collision frequency, speeding up reactions.
4) Catalysts - substances that increase a reaction's rate without being consumed. They do this by providing an alternative reaction pathway requiring less energy.
Students will be assigned experiments investigating how each of these factors impacts the rate of specific reactions.
1. The document discusses factors that affect the rate of chemical reactions, including temperature, concentration, pressure, surface area, and catalysts.
2. It explains that the rate of a reaction is measured by how concentration changes over time, and that rate laws use rate constants and reaction orders.
3. Different factors like increased temperature, concentration, or pressure speed up reactions by increasing the frequency of successful collisions between reactant particles.
Zimsec chemistry chapter 9 rate of reactionalproelearning
This document discusses factors that affect the rate of chemical reactions, including concentration, temperature, surface area, pressure, and catalysis. It defines rate of reaction, activation energy, and catalysts. It explains qualitatively how increasing concentration, temperature, and surface area increases the rate of reaction by increasing collision frequency and effective collisions. It describes how catalysts lower the activation energy of reactions, and enzymes act as biological catalysts with high specificity.
There are many types of chemical reactions including dissociation, ionization, combustion, precipitation, decomposition, displacement, and neutralization. Reaction rates depend on factors like temperature, concentration, and surface area. Reactions can range from very fast like explosions to very slow like the formation of diamonds. Common neutralization reactions include acids reacting with alkalis, metals, and metal oxides or carbonates to produce salts and water.
The document provides an outline and notes on the topics of rate of reaction, collision theory, factors affecting reaction rates, activation energy, endothermic and exothermic reactions, equilibrium, and Le Chatelier's principle. Key points include:
- Reaction rates can be determined by measuring how quickly reactants are used up or products are formed. Temperature, catalysts, surface area, and concentration can impact reaction rates.
- Collision theory states that reactants must collide with sufficient energy and correct orientation for a reaction to occur, forming an intermediate activated complex.
- Equilibrium is reached when the rates of the forward and reverse reactions are equal, though concentrations of reactants and products may not be equal.
-
The document provides information about various chemical reactions:
1. Decomposition reactions involve a single reactant breaking down into simpler products, such as ferrous sulfate decomposing into ferric oxide, sulfur dioxide, and sulfur trioxide when heated.
2. Displacement reactions occur when a more reactive element displaces a less reactive element from its compound, like iron displacing copper from copper sulfate solution.
3. Double displacement reactions involve the switching of ions between reactants to form new ionic compounds, exemplified by the reaction of barium chloride and sodium sulfate forming barium sulfate and sodium chloride.
4. Combination reactions form a single product from two or more reactants, such as calcium oxide react
The document discusses the rate of reaction in chemistry. It defines rate of reaction and explains how to calculate average and instantaneous rates. It describes four main factors that affect the rate of reaction: size of reactants, concentration, temperature, and presence of a catalyst. It introduces collision theory and activation energy to explain these factors. Students are asked to research examples of how each factor influences reaction rates and present their findings in a slideshow.
The document discusses key concepts related to chemical reaction rates including:
- Collision theory which states that molecules must collide with sufficient energy and correct orientation for a reaction to occur. This is known as an effective collision.
- Factors that affect reaction rates such as temperature, concentration, surface area, and the use of catalysts. Increased factors lead to more collisions and faster reactions.
- Activation energy which is the minimum energy needed for molecules to react. Catalysts provide an alternative reaction pathway with lower activation energy.
- Energy level diagrams which show reactants at a higher energy level than products for exothermic reactions, and lower for endothermic reactions.
Unit 1 Chemical reactions in our surroundingsalekey08
This document discusses chemical reactions and stoichiometry. It begins by defining physical and chemical changes, and chemical equations which represent chemical reactions symbolically. It then discusses various topics related to chemical reactions including reactants and products, balancing equations, reaction rates and factors that affect them. It also classifies common reaction types and discusses energy changes. Finally, it introduces stoichiometry, which uses mole ratios determined from balanced chemical equations to calculate amounts of reactants and products.
How to Install Theme in the Odoo 17 ERPCeline George
With Odoo, we can select from a wide selection of attractive themes. Many excellent ones are free to use, while some require payment. Putting an Odoo theme in the Odoo module directory on our server, downloading the theme, and then installing it is a simple process.
How to Store Data on the Odoo 17 WebsiteCeline George
Here we are going to discuss how to store data in Odoo 17 Website.
It includes defining a model with few fields in it. Add demo data into the model using data directory. Also using a controller, pass the values into the template while rendering it and display the values in the website.
Ardra Nakshatra (आर्द्रा): Understanding its Effects and RemediesAstro Pathshala
Ardra Nakshatra, the sixth Nakshatra in Vedic astrology, spans from 6°40' to 20° in the Gemini zodiac sign. Governed by Rahu, the north lunar node, Ardra translates to "the moist one" or "the star of sorrow." Symbolized by a teardrop, it represents the transformational power of storms, bringing both destruction and renewal.
About Astro Pathshala
Astro Pathshala is a renowned astrology institute offering comprehensive astrology courses and personalized astrological consultations for over 20 years. Founded by Gurudev Sunil Vashist ji, Astro Pathshala has been a beacon of knowledge and guidance in the field of Vedic astrology. With a team of experienced astrologers, the institute provides in-depth courses that cover various aspects of astrology, including Nakshatras, planetary influences, and remedies. Whether you are a beginner seeking to learn astrology or someone looking for expert astrological advice, Astro Pathshala is dedicated to helping you navigate life's challenges and unlock your full potential through the ancient wisdom of Vedic astrology.
For more information about their courses and consultations, visit Astro Pathshala.
The membership Module in the Odoo 17 ERPCeline George
Some business organizations give membership to their customers to ensure the long term relationship with those customers. If the customer is a member of the business then they get special offers and other benefits. The membership module in odoo 17 is helpful to manage everything related to the membership of multiple customers.
Integrated Marketing Communications (IMC)- Concept, Features, Elements, Role of advertising in IMC
Advertising: Concept, Features, Evolution of Advertising, Active Participants, Benefits of advertising to Business firms and consumers.
Classification of advertising: Geographic, Media, Target audience and Functions.
Delegation Inheritance in Odoo 17 and Its Use CasesCeline George
There are 3 types of inheritance in odoo Classical, Extension, and Delegation. Delegation inheritance is used to sink other models to our custom model. And there is no change in the views. This slide will discuss delegation inheritance and its use cases in odoo 17.
Split Shifts From Gantt View in the Odoo 17Celine George
Odoo allows users to split long shifts into multiple segments directly from the Gantt view.Each segment retains details of the original shift, such as employee assignment, start time, end time, and specific tasks or descriptions.
Credit limit improvement system in odoo 17Celine George
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The Jewish Trinity : Sabbath,Shekinah and Sanctuary 4.pdfJackieSparrow3
we may assume that God created the cosmos to be his great temple, in which he rested after his creative work. Nevertheless, his special revelatory presence did not fill the entire earth yet, since it was his intention that his human vice-regent, whom he installed in the garden sanctuary, would extend worldwide the boundaries of that sanctuary and of God’s presence. Adam, of course, disobeyed this mandate, so that humanity no longer enjoyed God’s presence in the little localized garden. Consequently, the entire earth became infected with sin and idolatry in a way it had not been previously before the fall, while yet in its still imperfect newly created state. Therefore, the various expressions about God being unable to inhabit earthly structures are best understood, at least in part, by realizing that the old order and sanctuary have been tainted with sin and must be cleansed and recreated before God’s Shekinah presence, formerly limited to heaven and the holy of holies, can dwell universally throughout creation
2. What you need to be able to do and understand
Energetics in Chemical Reactions Interpret data obtained from
Relate the terms exothermic and experiments concerned with speed of
endothermic to the temperature reaction.
changes observed during Describe the application of the above
chemical reactions. factors to the danger of explosive
Demonstrate understanding that combustion with fine powders (e.g.
exothermic and endothermic flour mills) and gases (e.g. mines).
changes relate to the Describe and explain the effects of
transformation of chemical temperature and concentration in
energy to heat (thermal terms of collisions between reacting
energy), and vice versa. particles (concept of activation
energy will not be examined).
Speed of Reactions Define catalyst as an agent which
Describe the effect of increases rate but which remains
concentration, particle unchanged.
size, catalysis and temperature
on the speeds of reactions. Redox
Describe a practical method for Define oxidation and reduction in
investigating the speed of a terms of oxygen loss/gain, and
reaction involving gas evolution. identify such reactions from given
Devise a suitable method for information.
investigating the effect of a given Define redox in terms of electron
variable on the speed of a transfer, and identify such reactions
reaction. from given information.
3. Endothermic and Exothermic Reactions
During a chemical reaction there is always an energy change
Exothermic: give out energy (heat, light or sound)
reactants → products + energy
The total energy is the same but the products have
lower energy than the reactants.
Endothermic: take in energy
reactants + energy → products
The total energy is the same but the products have
higher energy than the reactants since energy was
taken in.
A song to help you remember the
difference:
http://www.youtube.com/watch?v
=XgiCn1IpvzM
4. Which is which- Endothermic or Exothermic?
• A cold pack (for sport injuries)
• Endothermic
• The combustion of fuels
• Exothermic
• Firing a cannon
• Exothermic
• Cooking a steak
• Endothermic
• Cellular respiration
• Exothermic
• Photosynthesis
• Endothermic
5. Is this an exothermic or endothermic reaction?
Remember energy is measured in kilojoules (kJ)
CaCO3(s) → CaO(s) + CO2(g) the energy change is +178kJ
The + sign shows that energy is taken in
This is an endothermic reaction
Fe(s) + S(s) → FeS(s) the energy change is -100kJ
The - sign shows that energy is given out
This is an exothermic reaction
A little fun
6. Rates of Reactions
A rate is a measure of how fast or slow something is. Reactions can be slow or
fast.
Some fast reactions include: How can you measure the rate of
• Fireworks reaction?
• Wood burning
• Florescent light bulbs In general, to find the rate of a reaction, you
should measure:
Some slow reactions include:
• Rust forming on a car • the amount of a reactant used up/unit
• Food rotting time
• Cellular respiration OR
• the amount of a product produced/unit
time
A song to introduce rates of
reactions
http://www.youtube.com/watch?v=X
X9Xo6zm_kM
7. Factors that change reaction rates
The rate of a reaction depends on how many successful collisions there are in a
given unit of time
If we want to increase/decrease the number of
collisions what would we change?
• Temperature
• Concentration
• Surface area (particle size)
More animations on The Collision Theory:
We will use this animation to http://www.kentchemistry.com/links/Kinetics/FactorsAf
change some variables to see the fecting.htm
effect on the product
http://www.kscience.co.uk/animati
ons/collision.swf
8. Effect of concentration or temperature on the rate of a reaction
If the concentration or temperature of a reactant is increased the
reaction goes faster.
When the reactants have a higher temperature, they move faster, thereby increasing
the chance of a collision.
When the reactants have a lower temperature, they move slower, thereby decreasing
the chance of a collision.
When the reactants are less concentrated there is less chance of a collision.
When the reactants are more concentrated there is more chance of a collision.
An animation on temperature:
Why does this graph have a plateau?
http://www.ltscotland.org.uk/high
ersciences/chemistry/animation
s/collision_theory.asp
9. Effect of surface area (size of particle) on the rate of a reaction
If the surface area of a reactant is increased the reaction goes
faster.
Remember a collision involves surfaces.
Particles that are smaller have more surfaces to react with.
When the reactants are smaller there is more chance of a collision.
When the reactants are larger there is less chance of a collision.
Why does this graph
have a plateau?
10. Effect of a catalyst on the rate of a reaction.
If a catalyst is added the reaction goes faster.
A catalyst is a substance that speeds up a chemical reaction but remains chemically
unchanged itself.
Catalysts lower the activation energy needed to run
the chemical reaction – so it goes faster. The
reactants are able to react in a way that requires
less energy. This means that more collisions now
have enough energy to be successful
Enzymes are
biological catalysts
This animation give a good basic overview of enzymes A cool video showing
http://www.northland.cc.mn.us/biology/biology1111/ani catalysts!
mations/enzyme.swf
11. labs:
The effect of temperature on rate of reaction
The effect of particle size of rate of reaction
How would you design a lab to investigate
either one of these using steradent tablets?
You have 10 min to discuss
this with your neighbour
then you have 15 min to put
something in writing.
What do you think happens
when you dissolve an alka
setlzer tablet in space?
After which time we will
do one of them.
12. What happens when the reaction goes too fast?
BOOM!!!
There have been many examples when DUST (i.e. high surface area) of
flour, sugar, wood, or wheat explode. The dust from all of these can catch
fire and burn. If the reaction goes too fast you can get an explosion.
In mines methane and other flammable gasses can also have explosive
results if they are in high enough concentrations.
13. Oxidation and reduction – REDOX
- it’s all about oxygen
Oxidation: oxygen is gained
Iron is being oxidised to form iron(III) oxide- this is how rust forms.
Fe(s) + O2(s) →Fe2O3(s)
Fe gained oxygen
Reduction: oxygen is lost
If you heat magnesium oxide and carbon you get magnesium metal and
carbon monoxide. Magnesium oxide was reduced to magnesium metal.
MgO(s) + C(s) →Mg(s) + CO(g)
MgO lost oxygen
Two examples: which is which?
1- 2PbO2(s) → 2PbO(s) + O2(g) PbO2 lost oxygen
2- N2(g) + O2(g) → 2NO(g) N gained oxygen
14. But in reality…
Oxidation is accompanied by reduction.
For example, in the extraction of iron from its ore:
reduction So the reaction is
Iron(III)oxide lost oxygen called REDOX
Fe2O3 + 3CO → 2Fe + 3CO2
Carbon monoxide gained oxygen
oxidation
Because they always occur together we can
now define oxidation and reduction a bit
differently:
Oxidation is a loss of electrons. OIL RIG
Reduction is a gain of electrons. OxidationIs Losing
Reduction Is Gaining
IMPORTANT
15. REDOX in pictures When magnesium is burned, magnesium oxide
is formed. Magnesium has clearly oxidised
2Mg(s) + O2(g) → 2MgO(s) (gained an oxygen) but oxidation and reduction
always occur together. So oxygen was
reduced. But how does oxygen lose oxygen?
oxidation We need to look at the electrons.
2 electrons transfer
Mg2+ O2-
giving
Mg O Mg O
During the reaction each magnesium atom loses two electrons and each oxygen atom
gains two. Therefore magnesium was oxidized (loss of electrons) and oxygen was
reduced (gain of electrons).
Writing the half-equations:
Oxidation: 2Mg → 2Mg2+ + 4e-
Reduction: O2 + 4e- → 2O2-
16. REDOX without oxygen
Remember any reaction in which
electrons are transferred is a REDOX
2Na(s) + Cl2(g) → 2NaCl(s) reaction.
electron transfer
giving Cl-
Na+
Na Cl Na Cl
During the reaction each sodium atom loses one electron and each chlorine atom
gains one. Therefore sodium was oxidized (loss of electrons) and chlorine was
reduced (gain of electrons).
Writing the half-equations:
Oxidation: 2Na → 2Na+ + 2e-
Reduction: Cl2 + 2e- → 2Cl-
17. Have you learned anything?
Let’s check out this reaction rate online
simulation
http://phet.colorado.edu/en/simul
ation/reactions-and-rates