Reactions and Reaction Rates

Question 1

What is an element?

Answer 1

A substance containing only 1 type of atom

Question 2

What is a compound?

Answer 2

2 or more elements chemically combined

Question 3

What is a reactant?

Answer 3

A substance that takes part in a chemical reaction

Question 4

What is a product?

Answer 4

A substance produced in a chemical reaction

Question 5

What is ALWAYS produced in a chemical reaction?

Answer 5

A new substance

Question 6

What are the 5 signs of a chemical reaction?

Answer 6

Gas given off

Colour change

Smell

Energy change (temperature, light)

Solid formed

Question 7

How can we detect energy changes in a reaction?

Answer 7

Using a thermometer to detect change in temp

Feeling heat given off by a reaction

Hearing sound energy

Seeing Light energy

Question 8

How do reactions occur?

Answer 8

Particles of reactants collide.

( collision theory)

Question 9

Why do reactions stop?

Answer 9

Particles of one of the reactants “run out”

Question 10

What is the “limiting reactant”?

Answer 10

The reactant whose particles are all used up first

Question 11

What is the “excess reactant” ?

Answer 11

The reactant that still has particles present when the reaction stops.

Question 12

What is qualitative data?

Answer 12

Data based on judgement using the senses

Question 13

What is quantitative data?

Answer 13

Data based on measurements of quantity and / or time.

Question 14

What is meant by “independant” variable?

Answer 14

The thing we choose to change in an investigation

Question 15

What is meant by “ dependant” variable

Answer 15

The thing in a reaction that we measure as a result of the reaction

• volume of gas produced
• mass of reactants produced

Question 16

What name do we give to reactions that release heat?

Answer 16

Exothermic

Question 17

What name do we give to reactions that take in heat?

Answer 17

Endothermic

Question 18

What is the “independent variable” ?

Answer 18

The thing you have decided to change in an experiment

Question 19

What is the “dependent variable” ?

Answer 19

The thing that you are measured or observing

Question 20

What are the 2 main dependent variables used to calculate Rate of reaction

Answer 20

Volume of gas

Mass loss

Question 21

What dependant variables ( other than volume of gas and mass loss) could be measured as a reaction progresses?

Answer 21

concentration

pH

Question 22

What is apparatus for measuring mass as dependent variable in order to calculate Rate of reaction?

Answer 22

Question 23

What is apparatus for measuring gas volumes in order to claculate Rate of Reaction

Answer 23

Question 24

Why are catalysts used in industry?

Answer 24

Question 25

Name 4 ways to increase the rate of reaction

Answer 25

Increasing concentration of solution Increasing temperature

Adding a catalyst

Decreasing particle size

Question 26

What is meant by “collision theory”?

Answer 26

The idea that particles must collide in order to react

Question 27

How does decreasing particle size of a solid increase reaction rate?

Answer 27

Collision take place on the surface and the surface area is increased by decreasing particle size

Question 28

How does increasing concentration increase reaction rate?

Answer 28

More particles in given area means that particles will collide more often.

Question 29

What is meant by temperature?

Answer 29

Question 30

How does increasing temperature increase reaction rate?

Answer 30

The particles are moving faster and collide more often and with more energy.