Chemical Reactions

Question 1

How do you tell if there is a chemical reaction on a substance?

Answer 1

Sound, change in shape, smell, change in colour, change in temperature, sparks/flare, change in brightness, froth appearing and it might move.

Question 2

Can a physical change be reversed?

Answer 2

Yes

Question 3

Can a chemical change be reversed?

Answer 3

No

Question 4

Chemical reactions involve rearranging atoms or states?

Answer 4

Atoms

Question 5

Chemical reactions always make new substances. True or False?

Answer 5

True

Question 6

Chemical reactions are easily reversible. True or False?

Answer 6

False

Question 7

Physical changes include changes of substance or state?

Answer 7

State

Question 8

Physical changes are not reversible. True or False?

Answer 8

False

Question 9

Describe a chemical reaction.

Answer 9

When atoms are rearranged to make new substances

Question 10

What does a catalyst do?

Answer 10

Speeds up the reaction

Question 11

Describe the difference between a chemical and physical change.

Answer 11

A chemical change is irreversible whereas a physical change is not.

Question 12

What does a Metal + Oxygen make?

Answer 12

A Metal Oxide.

Question 13

What are the reactants in the reaction?

Answer 13

The substances being but together.

Question 14

In chemical reactions the total mass of the reactants wil be equal to what?

Answer 14

The product

Question 15

Magnesium + Oxygen makes what?

Answer 15

Magnesium Oxide

Question 16

If I heat iron with 1.2 grams of Sulphur and the product is 2.4 grams of Iron Sulphide, what was the other reactant and how much of it was there?

Answer 16

1.2 grams of Iron

Question 17

When balancing an equation, you can only put what in front of a substance?

Answer 17

The bigger number