Chapter 3:Controlling Chemical Reactions

In what way can a fire be brought under control?

Remove oxygen.

The minimum amount of energy that must be added to start a reaction is the _____ energy.

activation

What type of chemicals act as biological catalysts by speeding up reactions in living things?

enzymes

A reaction in which the reactants have more energy than the products is always a(n) _____ reaction.

exothermic

The greater the surface area, the _____.

faster the reaction

What is the best form of fire safety?

fire prevention

A fuel is a material that will release _____ when it burns.

heat

Which part of the fire triangle provides the activation energy needed to start a fire?

heat

What is a substance used to decrease the rate of a chemical reaction?

inhibitor

Without _____ in cells, the reactions in living things would occur too slowly or require temperatures that are too high for cells to survive.

the presence of enzymes

What is the purpose of the burning splint in the reaction?

to provide activation energy

_____ chemical reactions need a certain amount of activation energy to get started.

All

When you chew your food to break down the larger pieces into smaller particles, how are you helping to increase the rate of the chemical reactions in your body that breaks down your food?

By increasing the surface area.

How does a catalyst increase the rate of a chemical reaction?

By lowering the activation energy.

Why does putting baking soda on a fire put it out?

CO2 gas is produced cutting off the flow of oxygen.

What is the best way to put out a small kitchen fire?

Cover it with a pot lid.

Which is an example of how to supply activation energy to begin a reaction?

Heat the reaction flask on a hot plate.

Which of the following makes more particles of a substance available to react in a chemical reaction?

Increasing the concentration.

When two liquids are mixed in an endothermic reaction, what always happens to the temperature of the solution?

It gets colder.

Why does baking bread require a constant input of heat from the oven?

It is an endothermic reaction.

How is the rate of a chemical reaction related to temperature?

It is dependent upon the temperature.

If a burning candle is covered by a large glass beaker, the flame will go out. How does the beaker affect the conditions described by the fire triangle?

It prevents more oxygen from reaching the flame once the existing oxygen is used up.

Wood burns at a steady rate, but same mass of sawdust may explode if a spark ignites it. (Sawdust is tiny particles of wood made from sawing wood.) What explains this observation?

The sawdust has more surface area.

What starts the home fires that cause the most deaths?

cigarettes

Which describe a rapid reaction between oxygen and a fuel?

combustion

Which describes the amount of one material present in a given volume of another material?

concentration

A reaction in which the products have more energy than the reactants is always a(n) _____ reaction.

endothermic

What gas is necessary for combustion to take place?

oxygen

An endothermic reaction _____.

releases less energy than it uses

An exothermic reaction _____.

releases more energy than it uses