C5c- Quantitative analysis

Question 1

What are the units for concentration?

Answer 1

g/dm3 or mol/dm3

Question 2

What are the units for volume?

Answer 2

dm3 or cm3

Question 3

How many cm3 in 1 dm3?

Answer 3

1000cm3= 1dm3

Question 4

What are the particles like in a very concentrated solution?

Answer 4

There are more solute particles in a given volume and they are more crowded

Question 5

What is the equation for concentration?

Answer 5

Concentration = Moles ÷ Volume

Question 6

How would you work out how much water needs to be added to dilute 200cm3 of a 3mol/dm3 solution to get 200cm3 of a 1.5mol/dm3 solution?

Answer 6

1)Work out ratio of the 2 concentrations (smaller one first)
1.5 : 3
1 : 2
2) Write ratio as a fraction and multiply by volume you want
½ x 200 = 100cm3 (how much of the original solution you need to use)
3) Work out the volume of water you will need
200-100= 100cm3

Question 7

why is cordial diluted?

Answer 7

so the taste isn’t too strong

Question 8

why are medicines diluted?

Answer 8

to avoid giving overdoses

Question 9

why does baby milk have to be the right concentration?

Answer 9

so the baby isn’t harmed

Question 10

What is GDA?

Answer 10

guideline daily amount

Question 11

1 Naan Bread
Sugar - 5.4g (6%)
What does this tell you about GDA?

Answer 11

1 Naan Bread contains 6% of your daily sugar intake

Question 12

How do you convert sodium to salt?

Answer 12

x (58.5 ÷ 23)

Question 13

How do you convert salt to sodium?

Answer 13

x (23 ÷ 58.5)

Question 14

Why is the salt/sodium conversion inaccurate?

Answer 14

The sodium present in the food can come from compounds other than sodium chloride