Acids And Bases

Question 1

Describe a base

Answer 1

Turn red litmus paper blue
Have a pH above 7.
Many are corrosive and dangerous.
Alkalis are bases that are dissolved in water. An alkali is a base which is solvable in water.
Eg. Toothpaste, bleach, indigestion tablets.
Sodium hydroxide ( NaOH) and calcium carbonate (CaCo3).

Question 2

What is an indicator

Answer 2

A compound that shows, by colour change, whether a substance is acidic or basic.
Eg litmus paper

Question 3

Acid turns blue litmus

Answer 3

Red

Question 4

Bases or alkalis turn red litmus

Answer 4

Blue

Question 5

Blue to red means

Answer 5

Acid is present

Question 6

Red to blue means

Answer 6

Base or alkali is present

Question 7

Red to red means

Answer 7

It’s an acid or neutral

Question 8

Blue to blue means

Answer 8

It’s a base or an alkali or neutral

Question 9

What is the pH scale

Answer 9

A scale ranging from 0-14 which indicates the acidity or basicity of a solution

Question 10

Alkaline on a pH scale

Answer 10

Greater than 7

Question 11

Acid on ph scale

Answer 11

Less than 7

Question 12

Neutral on pH scale

Answer 12

7

Question 13

What is neutralisation

Answer 13

When the properties of an acid are counteracted or neutralised by a base; this type of reaction is called a neutralisation reaction.
The produce water and salt.
Both water and salt are neutral.

Question 14

Formula for neutralisation (general)

Answer 14

Acid + base = salt + water

Question 15

Neutralisation example word formula

Answer 15

Hydrochloric acid + sodium hydroxide = sodium chloride + water

Question 16

Neutralisation example chemical formula

Answer 16

HCL + NaOH = NaCl + H2O

Question 17

Neutralisation with carbonates (also bases) example word formula

Answer 17

Hydrochloric acid + calcium carbonate = calcium chloride + carbon dioxide + water

Question 18

Neutralisation with carbonates (also bases) example chemical formula

Answer 18

2HCl + CaCo3 = CaCl2 + CO2 + H2O

Question 19

What is a titration

Answer 19

Titration is a method of finding out the exact amount of acid needs to just neutralise a certain volume of base.

Question 20

Reaction of acids with metals word formula

Answer 20

Zinc + Hydrochloric acid = zinc chloride + hydrogen

Question 21

Reaction of acids with metals example chemical formula

Answer 21

Zn + 2HCl = ZnCl2 + H2

Question 22

Describe an acid

Answer 22

Have a sour taste.
Turn blue litmus paper red.
Have a pH less than 7.
Eg. Lemon juice (citric acid), rain water (carbonic acid), vinegar.
Hydrochloric acid (HCL) and Sulfuric acid (H2SO4).