Chemistry Chapter 4/5: Chemical Reactions

Questions and Answers

Mass can change forms during a chemical reaction.

Matter can be created from energy in a reaction.

The total mass of products is always greater than the reactants.

Matter cannot be created or destroyed in a chemical reaction. (correct)

Combination Reaction (correct)

Combustion Reaction

Decomposition Reaction

Oxidation Reaction

The mass of a mole of substances.

The number of particles in a mole of a substance. (correct)

The volume of liquids in a reaction.

The energy change during a reaction.

A reaction that releases energy as heat. Signup and view all the answers

The quantity of heat needed to change the temperature of 1 gram of a substance by 1 Celsius degree. Signup and view all the answers

The number of moles of a reactant or product. Signup and view all the answers

The breakdown of calcium carbonate into calcium oxide and carbon dioxide. Signup and view all the answers

Heat = mass x specific heat x ΔT Signup and view all the answers

Study Notes

Law of Conservation of Matter: Matter cannot be created or destroyed in a chemical reaction; total mass remains constant.
Reactant: Substance consumed in a chemical reaction.
Product: Substance produced as a result of a chemical reaction.
Coefficient: Number placed before a compound in a chemical equation to indicate the quantity of molecules or moles.
Stoichiometry: The calculation of reactants and products in chemical reactions based on balanced equations.
Combination Reaction: A reaction where two or more substances combine to form a single product.
Decomposition Reaction: A reaction where a single compound breaks down into two or more simpler substances.
Combustion Reaction: A rapid reaction between a substance and oxygen, producing heat and light, often involving the burning of hydrocarbons.
Oxidation: A process in a chemical reaction where an atom or molecule loses electrons.
Reduction: A process where an atom or molecule gains electrons in a chemical reaction.
Oxidation of Organic/Covalent Compounds: Involves increasing the number of bonds to oxygen or decreasing the number of bonds to hydrogen.
Reduction of Organic/Covalent Compounds: Involves decreasing the number of bonds to oxygen or increasing the number of bonds to hydrogen.

Be proficient in balancing chemical equations by ensuring the number of atoms for each element is equal on both sides.
Classify reactions as combination, decomposition, or combustion based on the reactants and products.
Identify whether an atom or molecule is oxidized (loses electrons) or reduced (gains electrons) in Redox reactions.

Moles: A unit for measuring quantity in chemistry that corresponds to Avogadro's number (approximately 6.022 x 10²³ particles).
Avogadro’s Number: The number of atoms, ions, or molecules in one mole of a substance.

Calculate molar masses by summing the atomic masses of all atoms in a molecular formula.
Perform conversions among moles, mass, and different units using chemical equations: mole-mole, mole-mass, mass-mole, and mass-mass.

Law of Conservation of Energy: Energy cannot be created or destroyed, only transformed from one form to another.
Energy: The capacity to do work or produce heat, existing in various forms such as kinetic and potential energy.
Heat: The energy transferred between objects at different temperatures, flowing from hot to cold.
Units for Heat: Commonly measured in joules (J) or calories; 1 dietary Calorie = 1,000 calories.
Specific Heat: The amount of heat required to raise the temperature of 1 gram of a substance by 1°C.
Phase Change: The transition between solid, liquid, and gas states, involving energy absorption or release.
Melting Point: The temperature at which a solid turns into a liquid.
Boiling Point: The temperature at which a liquid becomes a gas.
Isothermal: A process that occurs at constant temperature.
Exothermic Reaction: A reaction that releases heat into the surroundings, resulting in an increase in temperature.
Endothermic Reaction: A reaction that absorbs heat from the surroundings, causing a decrease in temperature.

Solve heat calculations using the formula: heat = mass x specific heat x ΔT, interpreting each variable correctly.
Utilize the formula: heat = mass x ΔHvap/fus for phase change calculations, applying the correct latent heat values.
Analyze reaction equations or energy diagrams to discern whether a reaction is endothermic or exothermic by observing heat exchange.