CW

Question 1

What is the neutralisation reaction word equation?

Answer 1

Acid + base > salt + water

Question 2

How do you recover the salt in neutralisation?

Answer 2

Using the evaporation technique. The solution is poured in an evaporating basin, which is heated by a bunsen burner and left to evaporate until salt crystals have been formed.

Question 3

What is an indicator?

Answer 3

Indicators can tell whether a substance is an acid or base by changing colour.

Question 4

What are some examples of indicators?

Answer 4

Some common indicators are: universal indicator, litmus, methyl orange.

Question 5

What does PH stand for?

Answer 5

Potential of Hydrogen.

Question 6

All matter is…

Answer 6

composed of atoms and has mass.

Question 7

What is the rule concerning matter?

Answer 7

Matter can neither be created or destroyed in a reaction. The total number of atoms in the reactants = the total number of atoms in the products.

Question 8

What are compounds?

Answer 8

Compounds are new substances that are formed in chemical reactions when atoms rearrange. A compound is two or more elements joined together chemically.

Question 9

Identify the chemical formula for the compound: Water

Answer 9

H2O

Question 10

Identify the chemical formula for the compound: Sodium Chloride

Answer 10

NaCl

Question 11

When does a neutralisation reaction occur?

Answer 11

Neutralisation reactions occur when an acid and a base chemically react with one another to produce a salt and water.

Question 12

What are some examples of neutralisation reactions in the home.

Answer 12

• Neutralisation of Acids caused by bacteria in your mouth and toothpaste
• Neutralisation of acids in your stomach and antacid tablets

Question 13

An acid and a metal chemically react to produce what?

Answer 13

A salt and a hydrogen gas.

Question 14

What is the general word equation that is used to describe an acid-metal reaction?

Answer 14

Acid + Metal ———> salt + hydrogen
An example acid-metal reaction is the pop-test which is achieved by reacting magnesium ribbon (metal) and hydrochloric acid which produces hydrogen (H2): Mg + HCl———> MgCl + H2
(REACTANTS) (PRODUCTS)

Question 15

Identify the chemical formula for the compound: Citris Acid

Answer 15

C6H8O7

Question 16

Identify the chemical formula for the compound: Sulfuric Acid

Answer 16

H2SO4

Question 17

Identify the chemical formula for the compound: Carbon Hydroxide

Answer 17

CH4

Question 18

What happens during a chemical reaction?

Answer 18

A chemical reaction is said to have occurred when a new product is formed. Atoms from the original chemicals, also known as reactants are rearranged to form new products in a chemical reaction.

Question 19

What is a chemical equation?

Answer 19

A chemical equation is a way of communicating specific information about a reaction. Chemical equations can be written in words or they can be written using molecular formulae Eg. Word equation
Hydrogen + Oxygen —> water
H2 + O —-> H2O

Question 20

What does the arrow in a chemical equation mean?

Answer 20

The arrow must be used in chemical equations. It means “produces”

Question 21

What do indicators do?

Answer 21

Indicators can tell whether a substance is an acid or base by changing colour.

Question 22

Some common indicators are…

Answer 22

Universal Indicator, Litmus, methyl orange.

Question 23

What are reactants and products?

Answer 23

Reactants - starting materials/chemicals in a reaction

Products - new chemicals formed by a reaction

Question 24

What is an exothermic reaction?

Answer 24

An exothermic reaction is a chemical reaction that releases energy by light or heat.

Question 25

What is an endothermic reaction?

Answer 25

An endothermic reaction is a chemical reaction in which the system absorbs energy from its surroundings eg. Photosynthesis, Melting Ice, Baking Bread, Cooking an Egg

Question 26

Chemical reactions involve energy transfer and can either be...

Answer 26

exothermic or endothermic.

Question 27

What is corrosion?

Answer 27

The decay (loss of metallic properties in strength, lustre or shine, and electrical conductivity) of a metal that occurs when a metallic substance oxidises after exposure to gases or liquids.

Question 28

What is a chemical equation of corrosion?

Answer 28

Fe + O2 > FeO2 | Metal + oxygen > metal oxide

Question 29

Ways to prevent corrosion

Answer 29

* Turn to non-corrosive metals such as Aluminium and stainless steel. * Keep the area around the metal surface dry. * Use drying agents and moisture barrier products. * Use corrosive inhibitors (lacquers, painting, grease oil * Galvanising (cover the metal with zinc to slow down the corrosive process)

Question 30

THE RATE OF A CHEMICAL REACTION CAN BE CHANGED BY ALTERING THE TEMPERATURE. If the temperature is increased...

Answer 30

- The reactant particles move more quickly - They have more energy - The particles collide more often because of this, and more of the collisions are successful - Thus the rate of reaction increases.

Question 31

THE RATE OF A CHEMICAL REACTION CAN BE CHANGED BY ALTERING THE TEMPERATURE. If the temperature is decreased...

Answer 31

- Molecules are slower - Collide less *sometimes you will mix solutions in ice so that the temperature of the system stays cold and the rate of reaction is slower*