Mechel Golenberke: My First Website
Chapter 7 Chemical Reactions
Video: Chemical Reactions (17:22)
Chapter 7 Vocabulary Worksheet
7.1 Describing Reactions
7.1.1 Interpret chemical equations in terms of reactants, products and conservation of mass
7.1.2 Balance chemical equations by manipulating coefficients
7.1.3 Convert between moles and mass of a substance using molar mass
7.1.4 Calculate amounts of reactants or products by using molar mass, mole ratios, and balanced chemical equations
- The law of conservation of mass states that mass is neither created nor destroyed.
- In order to show that mass is conserved during a reaction, a chemical equation must be balanced.
- Because chemical reactions often involve large numbers of small particles, chemists use a unit called the mole to measure amounts of a substance.
- In chemical reactions, the mass of a reactant or product can be calculated by using a balanced chemical equation and molar masses.
7.1 PowerPoint slides 1-34 (balancing equations) & Note Guide
**Active Art: Activity on Balancing Equations
Articles on Chemical Reactions
**Teachers Guide to Balancing Chemical Equations – you tube video
Pearson Chapter 7 Chemical reactions – Chemical reactions (Math Skill)
7.1 Describing reactions – Math Skills & Problem Solving Workbook
Prentice Hall Worksheets:
Chapter 3: Counting Atoms, Balancing Act, Balancing Equations
Chapter 8: A Balancing Act, A Balancing Act b, Balancing Equations
Fun Activities: Classic Chembalancer & Classic Chembalancer Worksheet
Review Chembalancer & Review Chembalancer Worksheet
Use this worksheet for the "Snowman Challenge" game. Use this master for the front of the cards and this one for the back of the cards. Snowman Challenge Student Chart – Snowman Challenge Answers
ChemFiesta Worksheet: Balancing Equations - quiz
Balancing Chemical Equations Activity: pdf student pages 1 & 3, pdf student page 2, activity cards page 1, activity cards page 2
Brightstorm: Chemical Reactions Law of Conservation of Mass (1:56)
The law of conservation of mass states that mass is neither created nor destroyed. In a closed system, mass of reactants is equal to mass of products. The law of conservation of mass is related to the law of conservation of matter.
Brightstorm: Chemical Reactions Chemical Equations (4:43)
A chemical equation shows the reactants and the products of a chemical reaction. Balancing chemical equations is necessary because the same atoms should be present before and after the reaction, just in different arrangements. A balanced chemical equation is useful in showing us the ratios of reactants and products.
Brightstorm: Chemical Reactions Balancing Chemical Equations (6:57)
Balancing chemical equations allows us to find the proper ratios of reactants and products within a chemical equation. In a balanced chemical equation, the same atoms are present on each side of the equation, but simply rearranged. A balanced chemical equation has the same number of atoms of each element on both reactant and product sides of the equation.
7.1 PowerPoint slides 35-57 (moles & chemical calculations) & Note Guide
reactant – a substance that undergoes change in a chemical reaction
products – new substances formed as a result of a chemical reaction
chemical equation – a representation of a chemical reaction in which the reactants and products are expressed as formulas
coefficients – numbers that appear before a formula in a chemical equation to show the relative proportions of each reactant and product
mole – an amount of a substance that contains approximately 6.02 x 1023 particles of the substance
molar mass – the mass of one mole of a substance
The Mole: Mr. Gilliland Honors Physical Science
Mr. Guch Molar Mass Explanation
Mr. Guch All About Mole Calculations
Molar Mass Worksheet & Molar Mass Practice Worksheet
Fun With Moles Activity: Student Pages
Brightstorm: Chemical Reactions Molar Mass (5:32)
The molar mass of a substance is the mass of one mole of that substance. Because of the nature of the mole, the atomic mass of an element in atomic mass units is equal to the molar mass of that substance in grams. Molar mass is useful in finding the number of moles of a substance within a given sample.
Brightstorm: Chemical Reactions Chemistry Mole (5:16)
In chemistry, the mole, also called Avogadro’s Number, is a unit that is useful in converting between atomic mass and molar mass. One mole is 6.02 x 10^23 of something, which was derived from the number of atoms in 12 grams of carbon-12.
Hopscotch Moles Activity – Teacher’s Guide with formula for Chalk
Moles Worksheet, Moles, Molecules & Grams Worksheet, Grams/Moles Calculations, Mole Calculation Worksheet
7.2 Types of Reactions
7.2.1 Classify chemical reactions as synthesis, decomposition, singular-replacement, double-replacement, or combustion reaction
7.2.2 Describe oxidation-reduction reactions, and relate them to other classifications of chemical reactions
- The general types of chemical reactions are synthesis reactions, decomposition reactions, single-replacement reactions, double-replacement reactions, and combustion reactions.
- Scientist classify certain chemical reactions as transfers of electrons between atoms.
7.2 PowerPoint & Note Guide
synthesis reaction – a chemical reaction in which two or more substances react to form a single substance
decomposition reaction – a chemical reaction in which a compound breaks down into two or more simpler substances
single-replacement reaction – a chemical reaction in which one element takes the place of another element in the compound
double-replacement reaction – a chemical reaction in which two compounds exchange positive ions and form two new compounds
combustion reaction – a chemical reaction in which a substance reacts rapidly with oxygen, often producing heat and light
oxidation-reduction reaction – a chemical reaction in which electrons are transferred from one reactant to another
"Cartoon Chemistry" worksheet - from Mrs. Griffin Website – Chemical Reaction page
YouTube:
Five Major Chemical reactions (1:36) – animation explaining five major types of chemical reactions
Chemical Reactions (3:30) – 4 types of chemical reactions explained using celebrity relationships
Intro to Chemistry 4.3 Types of Chemical Reactions (10:09) – nice lesson, but only synthesis – Challenger footage
The Five Major Class of Chemical Reaction (1:30) – videos of the reactions
Brightstorm: Chemical Reactions Types of Reactions (6:02)
Scientists classify different types of chemical reactions using their behavior. Types of reactions include single displacement, double displacement, synthesis, decomposition and combustion.
Brightstorm: Chemical Reactions Synthesis Reactions (3:32)
A synthesis reaction is a type of reaction in which multiple reactants combine to form a single product. Synthesis reactions release energy in the form of heat and light, so they are exothermic. An example of a synthesis reaction is the formation of water from hydrogen and oxygen. Synthesis is, in essence, the reversal of a decomposition reaction.
Brightstorm: Chemical Reactions Combustion Reactions (4:32)
A combustion reaction (commonly known as “burning”) is an exothermic reaction in which something reacts with oxygen. The combustion of organic compounds usually takes the form organic compound + oxygen => water + carbon dioxide.
Brightstorm: Chemical Reactions Decomposition Reaction (2:42)
A decomposition reaction is a reaction in which a single reactant produces multiple products. An example of a decomposition reaction is when water is broken down into hydrogen and oxygen. In essence, decomposition is the opposite of a synthesis reaction.
Brightstorm: Chemical Reactions Single Replacement Reaction (8:42)
In a single replacement reaction, a single element replaces an atom in a compound producing a new compound and a pure element. Like double replacement reactions, metals always replace metals and nonmetals always replace nonmetals in a compound.
Brightstorm: Chemical Reactions Double Replacement Reactions (5:32)
In a double replacement reaction, two compounds swap atoms forming two different compounds. Like single replacement reactions, metals always replace metals and nonmetals always replace nonmetals. Double replacement reactions often produce precipitates when non-soluble compounds are produced.
Brightstorm: Chemical Reactions Net Ionic Equation (9:37)
A net ionic equation is an equation for a double replacement reaction which shows only the reacting ions and omits the spectator ions.
Brightstorm: Chemical Reactions Stoichiometry (7:49)
Stoichiometry is the study of measuring or predicting the amount of reactants or products in a chemical reaction based on the variables such as the mass of reactants or products, the limiting reactant and the balanced chemical equation.
Brightstorm: Chemical Reactions Percent Yield (5:16)
Reactions don’t always go to completion. In the lab, chemists usually produce less reactants than anticipated. We represent the amount we produced as percent yield, which represents the percent of the anticipated yield we actually produced. The formula for percent yield is percent yield = 100 x absolute value (actual yield / predicted yield).
Brightstorm: Chemical Reactions Limiting Reactants (8:46)
Limiting reactants are reactants in chemical reactions which limit how much product can be formed. The limiting reactant is the reactant we run out of first, leaving the other reactants in excess. When predicting how much product we anticipate producing, we have to take the limiting reactant into account.
7.3 Energy Changes in Reactions
7.3.1 Describe the energy changes that take place during chemical reactions
7.3.2 Classify chemical reactions as exothermic or endothermic
7.3.3 Explain how energy is conserved during chemical reactions
- Chemical reactions involve the breaking of chemical bonds in the reactants and the formation of chemical bonds in the products.
- During a chemical reaction, energy is either released or absorbed.
7.3 PowerPoint & Note Guide
chemical energy – the energy stored in chemical bonds
exothermic reaction – a chemical reaction that releases energy to its surroundings
endothermic reaction – a description of a change in which a system absorbs energy from its surroundings
7.4 Reaction Rates
7.4.1 Explain what a reaction rate is
7.4.2 Describe the factors affecting chemical reaction rates
- Reaction rates tell you how fast a reaction is going.
- Factors that affect reaction rates include temperature, surface area, concentration, stirring and catalysts.
7.4 PowerPoint & Note Guide
reaction rate – the rate at which reactants change into products over time
catalyst – a substance that affects the rate of a chemical reaction without being used up in the reaction
Links on Factors Affecting Reaction Rates
Brightstorm: Chemical Reaction Rates Collision Theory (1:51)
Collision theory is a model for explaining chemical reactions and reaction rates using the interactions of particles within the reactants. There are three important parts to collision theory, that reacting substances must collide, that they must collide with enough energy and that they must collide with the correct orientation. Increasing the kinetic energy of these particles or decreasing their volume increases the frequency of collisions and speeds a reaction.
Brightstorm: Chemical Reaction Rates Reaction Rates Factors (3:05)
There are several factors that affect reaction rates. Their effects can be explained using collision theory. These factors are the nature of the reactants, concentration, surface area, temperature and catalysts. Each of these factors increases reaction rate because they increase the number or energy of collisions.
Brightstorm: Chemical Reaction Rates Reaction Mechanism (6:05)
A reaction mechanism is a series of steps which allows complex reactions to proceed. Explained in terms of collision theory, it is unlikely for more than two particles to collide at the same time with the proper orientation, so reactions involving several reactants are actually composed of several simpler reactions happening in close succession. Often an a substance which is created in one step and used in the next, called an intermediate, is formed.
Brightstorm: Chemical Reaction Rates Reaction Rate Laws (9:16)
Reaction rate laws give an equation for finding the rate of a reaction using the concentration of the reactants and the stoichiometric coefficients. For the chemical equation aA +bB => C the reaction rate law is reaction rate = k[A]^a [B]^b where k is a constant.
Brightstorm: Chemical Reaction Rates Reaction Rate Problems (9:38)
In class, you may often be asked to solve different types of reaction rate problems. When solving reaction rate problems, it is important to remember the reaction rate laws and the basics of balancing equations.
Brightstorm: Chemical Reaction Rates Energy Diagrams (3:49)
Energy diagrams depict the reaction progress versus energy. For exothermic reactions, the reactants are drawn above the products because their energy is greater. However, for endothermic reactions, the reactants are drawn below the products. Catalysts lower activation energy, so they decrease the size of the hump within the diagram itself.
7.5 Equilibrium
7.5.1 Identify and describe physical and chemical equilibria
7.5.2 Describe the factors affecting chemical equilibrium
- When a physical change does not go to completion, a physical equilibrium is established between the forward and reverse changes. When a chemical reaction does not go to completion, a chemical equilibrium is established between the forward and reverse reactions.
- When a change is introduced to a system in equilibrium, the equilibrium shifts in the direction that relieves the change.
7.5 PowerPoint & Note Guide
equilibrium – a state in which the forward and reverse paths of a physical or chemical change take place at the same rate
reversible reaction – a chemical reaction in which the conversion of reactants into products and the conversion of products into reactants happen at the same time
Links on factors Affecting Equilibrium
Brightstorm: Chemical Equilibrium Chemical Equilibrium Definition (5:01)
The definition of chemical equilibrium is the point at which the concentrations of reactants and products do not change with time. It appears as though the reaction has stopped but in fact the rates of the forward and reverse reactions are equal so reactants and products are being created at the same rate
Brightstorm: Chemical Equilibrium Heterogeneous Equilibrium - Homgeneous Equilibrium (3:21)
Homogeneous and heterogeneous equilibrium is a system of chemical equilibrium which depend upon the states of matter of the substances involved. Homogeneous equilibrium involves substances in the same state. Heterogeneous equilibrium involves substances in different states. The position of heterogeneous equilibrium does not depend on the amount of pure solid and liquid present.
Brightstorm: Chemical Equilibrium Le Chatelier's Principle (2:22)
Le Chatelier's principle states that when a change in concentration, pressure, or temperature is applied to a system at equilibrium, the position of the equilibrium shifts in direction that tends to reduce the effect of that change. For instance if an amount of reactant of the product is added, the system shifts towards the removed component.
Brightstorm: Chemical Equilibrium Equilibrium Changes (6:46)
Equilibrium changes are caused by Le Chatlier’s Principle and depend upon the stress applied. Le Chatelier’s Principle predicts the direction of change. For changes in volume, it is important to note that volume and pressure are inversely related. The effect of a change in concentration would increase or decrease in molecular collisions and increase or decrease the rate of forward and reverse reactions accordingly. The result from the effect of a change in temperature can either be exothermic, in which energy is released or endothermic, in which energy is consumed.
Brightstorm: Chemical Equilibrium Calculating Equilibrium Concentrations (video coming soon)
The general steps of calculating equilibrium concentrations are to first write out the expression of equilibrium constant, then impute the known concentration value of each element given, and finally solve for the unknown value. When dealing with equilibrium, it is important to remember that solids and liquids are not affected.
Brightstorm: Chemical Equilibrium Solubility Equilibrium (4:17)
Solubility equilibrium is the equilibrium associated with dissolving solids in water to form aqueous solutions. At the point where no more solid can dissolve, the solution is saturated. The solubility product constant is an equilibrium constant used in solubility equilibrium.
Also from Mrs. Griffin: WebQuest: Chemistry of Fireworks
