Energy Changes Combined Science

What does the law of conservation of energy state?

• Energy can only be transferred from one form to another

• The amount of energy in the universe remains constant

• The universe is losing energy

• Energy can be created and destroyed

What is an exothermic reaction?

• A reaction that only occurs in photosynthesis

• A reaction that does not involve energy transfer

• A reaction that absorbs energy from the surroundings

• A reaction that transfers energy to the surroundings

Which of the following is an example of an endothermic reaction?

• Neutralization

• Oxidation

• Combustion

• Thermal decomposition of metal carbonates

What is the independent variable in the described required practical?

• The temperature change

• The volume of acid used

• The different metals being added

• The concentration of acid

What is activation energy?

• The minimum amount of energy required for a reaction to proceed

• The energy released during a reaction

• The total energy absorbed in a reaction

• The energy stored in chemical bonds

What does a catalyst do in a chemical reaction?

• Increases the activation energy

• Provides an alternative pathway with a higher activation energy

• Decreases the overall energy change

• Provides an alternative pathway with a lower activation energy

In an exothermic reaction, the energy level of the products compared to the reactants is:

• Unpredictable without specific data

• The same

• Lower

• Higher

Which of the following is a characteristic of a chemical change?

• Change in state of matter

• Change in color and production of gas

• Change in temperature without energy transfer

• Reversible physical change

What role does temperature play in a chemical reaction?

• It has no effect on the reaction rate

• Decreasing temperature always speeds up the reaction

• Increasing temperature generally increases the reaction rate

• Temperature changes only affect exothermic reactions

How does the concentration of reactants affect the rate of reaction?

• Higher concentration always decreases the reaction rate

• There is no relationship between concentration and reaction rate

• Lower concentration increases the time for reaction completion

• Higher concentration of reactants generally increases the reaction rate