Matter/Chemical Change - Section 4

Question 1

What are reactants?

Answer 1

The materials that start a reaction

Question 2

What are products?

Answer 2

The new materials produced in a reaction

Question 3

What is an exothermic reaction?

Answer 3

A chemical reaction that releases heat

Question 4

What are some examples of an exothermic reaction?

Answer 4

When wood is burned it releases light and heat

When food is metabolized it releases heat energy

Question 5

What is an endothermic reaction?

Answer 5

A chemical reaction that absorbs heat

Question 6

What are some examples of an endothermic reaction?

Answer 6

Cold packs contain a chemical that absorbs a lot of heat when it dissolves in water. This causes the bag to feel cold

Question 7

What are the three types of reactions in which oxygen reacts with other substances?

Answer 7

Combustion
Corrosion
Cellular respiration

Question 8

What is a combustion reaction?

Answer 8

A chemical reaction that occurs when oxygen reacts with a substance to form two new substances and give off energy
The products are always carbon dioxide and water

Question 9

What is a corrosion reaction?

Answer 9

A slow chemical change that occurs when oxygen in the air reacts with metal

Question 10

What is a cellular respiration reaction?

Answer 10

Is a chemical reaction that takes place in the cells in your body
It is the opposite chemical to photosynthesis in plants
Technically is a type of combustion reaction though it takes place more slowly

Question 11

What is the Law of Conservation of Mass?

Answer 11

The total mass of the products is always equal to total mass of reactants
Therefore matter is not created or destroyed

Question 12

Why is it important to have a closed system when conducting an experiment

Answer 12

Then products that are in the form of a gas can escape if it is not a closed system

Question 13

What are the four factors that can affect the rate or speed of a chemical reaction?

Answer 13

The presence of a catalyst
The concentration of the reactants
The temperature of the reactants
The surface area of the reactants

Question 14

What are catalysts?

Answer 14

Are substances that help the reaction proceed faster usually by lowering the amount of energy required for the chemical reaction to happen
They are not consumed during the reaction

Question 15

What is concentration?

Answer 15

Refers to the proportion of a dilute to the solvent of a solution
For the substances involved in a chemical reaction the greater the concentration of the reactants the faster the reaction

Question 16

What are the two ways concentration can be increased?

Answer 16

Increase the amount of solute

Decrease the amount of solvent

Question 17

How does temperature effect the the rate of a chemical reaction?

Answer 17

As heat is added to the reactants, the faster the reaction between them can occur
Added heat causes atoms to move faster, increasing their chances of colliding with each other

Question 18

What is surface area?

Answer 18

Refers to the total area of all the surfaces of each substance
The greater the surface area is available for reaction causing the reaction to occur faster