Unit1Topic8 - Acids, Bases & Salts

Question 1

Toxic

Answer 1

Use a fume cup board

Question 2

Flammable

Answer 2

No naked flames in laboratory when using flammable substances

Question 3

Corrosive

Answer 3

Wear protective gloves and other personal protective equipment

Question 4

Indicator definition

Answer 4

An indicator is a dye that changes colour according to whether it is an acidic or alkaline solution.

Question 5

Phenolphthalein

Answer 5

Acid: colourless
Neutral: colourless
Alkali: pink

Question 6

Universal indicator

Answer 6

Strong acid, 0-2, red, e.g. car battery acid, stomach acid

Weak acid, 3-6, orange/yellow, e.g. vinegar, acid rain, normal rain, lemon juice

Neutral, 7, green, e.g. tap water, milk

Weak alkali, 8-11, blue, e.g. washing up liquid, ammonia

Strong alkali, 12-14, purple, e.g. soap powder, sodium hydroxide

Question 7

Benefits of using a pH meter over other indicators

Answer 7

More accurate (2dp)

There are also solutions of strong acids with a negative pH - can only be measured with pH meter

Question 8

Properties of acids

Answer 8

Sour taste

Corrosive