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GSHS Edexcel Chemistry > Acids > Flashcards

Flashcards in Acids Deck (24)
1

What measurement do we use to see how acidic or alkaline a substance is?

pH scale

2

What is the pH of an acid?

pH 1-6

3

What is the pH of an alkali?

pH 8-14

4

What name is given to a substance that changes colour depending on how acid or alkaline a substance is?

Indicator

5

Name 3 indicators

Any 3: universal indicator, litmus, methyl orange, phenolphthalein

6

How do you describe a substance with pH7?

Neutral

7

Name three acids

Any 3: Hydrochloric, nitric, sulphuric, ethanoic

8

Name an alkali

Sodium hydroxide

9

Name two neutral substances

Water, salty water

10

Why are concentrated acids and alkalis hazardous?

They are corrosive

11

Why are dilute acids and alkalis hazardous?

They are irritants

12

What safety precautions should you make when using acids and alkalis

Wear goggles, wear gloves

13

When acids dissolve in water, what ions do they release?

Hydrogen ions, H+

14

When alkalis dissolve in water, what ions do they release?

Hydroxide ions, OH-

15

What is a base?

A substance that reacts with an acid in a neutralisation reaction

16

What is an alkali?

A soluble base, e.g. sodium hydroxide

17

What happens to the H+ and OH- ions from the acid and base during neutralisation?

They react together to form water:
H+ + OH- --> H2O

18

What factor does an acid need to be diluted by to increase the pH by 1?

10

19

What factor does an alkali need to be diluted by to decrease the pH by 1?

10

20

What is the difference between a strong acid and a weak acid?

Strong acids fully dissociate, weak acids slightly dissociate

21

What is the difference between a concentrated acid and a dilute acid?

Concentrated acids have lots of acid particles in a given volume. Dilute acids have fewer particles in a given volume.

22

What are the units for concentration?

mol/dm3 (moles per cubic decimetre)

23

Two acids have H+ concentrations of 1mol/dm3 and 0.001mol/dm3. What is the difference in pH?

3

24

Two alkalis have OH- concentrations of 0.1 and 0.00001mol/dm3. What is the difference in pH?

4