C1.3 Chemical Reactions

Question 1

What do chemical reactions do?

Answer 1

It tranfers energy to or from the surroundings. Also it makes new substances.

Question 2

Are chemical reactions easily reversible?

Answer 2

No

Question 3

How can you tell if a chemical reaction has taken place?

Answer 3

There could be a colour change, a noise, bubbles/fizzing, a change of temperature, a smell

Question 4

How can you speed up a chemical reaction?

Answer 4

Increase the temperature of the reactants or use a catalyst

Question 5

Is a catalyst used up in a chemical reaction?

Answer 5

No

Question 6

A reversible change is often a?

Answer 6

Physical change

Question 7

What do we call two or more elemetns chemically joined?

Answer 7

A compound

Question 8

Does a compound have the same properties of the elements that make it up?

Answer 8

No

Question 9

Which side does reactants go in a chemical equation?

Answer 9

Left

Question 10

Which side does products go in a chemical equation?

Answer 10

Right

Question 11

What does the arrow mean?

Answer 11

reacts to make

Question 12

When magnesium and oxygen react it produces?

Answer 12

Magnesium Oxide

Question 13

What is a fuel?

Answer 13

A material that burns to transfer energy by heating

Question 14

State some examples of fuel

Answer 14

Petrol, diesel, coal, hydroge and cooking oil

Question 15

What is combustion?

Answer 15

A chemical reaction that involves burning

Question 16

What is oxidation?

Answer 16

A form of combustion where a reactant reacts with oxygen

Question 17

State an example of oxidation

Answer 17

Rusting

Question 18

What does non-renewable mean?

Answer 18

That the object is not replacable in our lifetimes

Question 19

What does thermal decomposition mean?

Answer 19

Where a complex compound breaks down into simpler compounds and elements through heating

Question 20

Name an example of thermal decomposition

Answer 20

Hydrogen Peroxide –> water + oxygen

Question 21

In the thermal decomposition of carbonates, which gas is always given off?

Answer 21

Carbon Dioxide

Question 22

How can you tell if carbon dioxide is a product?

Answer 22

Place it through lime water, if the lime water turns cloudy, carbon dioxide was present

Question 23

What type of data is needed to draw a bar chart?

Answer 23

Discrete or categoric data

Question 24

What does conservation of mass mean?

Answer 24

The total mass of reactants is the same as the total mass of products

Question 25

If the mass of the products seems to have decreased - what must have happened?

Answer 25

At least one of the products was a gas - which escapes and lowers the mass of the remaining products

Question 26

If the mass of the products seems to have increased - what must have happened?

Answer 26

At least one of the reactants was a gas - this then chemically joins another reactant to make the product heavier

Question 27

How can you balance equations?

Answer 27

By writing numbers BEFORE the chemical symbols

Question 28

What does a balanced equation mean?

Answer 28

Same number of each elements before and after the reaction