Concentration

Question 1

Strong acid

Answer 1

~ low pH

~ easily dissociates to give H+ ions

Question 2

Concentrated acid

Answer 2

~ high amount of H+ ions in a given volume

Question 3

Dilute acid

Answer 3

~ low amount of H+ ions in a given volume

Question 4

Weak acid

Answer 4

~ high pH (still below pH 7 though)

~ doesn’t dissociate easily

Question 5

How would you work out concentration?

Answer 5

Concentration = amount dissolved / volume of solution

Question 6

What is the units used for concentration?

Answer 6

Grams per decimetre cubed - g dm-3

Question 7

What does the minus sign show in the units for concentration?

Answer 7

It shows that g is divided by dm3

Question 8

Units in questions are usually given as cm3. How would you change that to dm3?

Answer 8

Divide cm3 by 1000 to change into dm3

Question 9

If 4g is dissolved in 50cm3 of a liquid, what is the concentration of the solution made?

Answer 9

50cm3 = 0.05dm3
Concentration = amount dissolved / volume of solution 
Concentration = 4 / 0.05
Concentration = 80g dm-3

Question 10

What would happen to magnesium if it is dropped into a solution of a strong and concentrated acid?

Answer 10

~ fizzes
~ heats up
~ steams

Question 11

What would happen to magnesium if it is dropped into a solution of a strong and dilute acid?

Answer 11

~ small amount of fizzing

Question 12

What would happen to magnesium if it is dropped into a solution of a weak and concentrated acid?

Answer 12

~ fizzing

~ cloudy

Question 13

What would happen to magnesium if it is dropped into a solution of a weak and dilute acid?

Answer 13

~ nothing

Question 14

What is the difference in concentration of H+ ions?

Answer 14

x 10 (going down from 7)
0      1      2      3      4      5      6      7