Quantitative Analysis

Question 1

What happens when concentration increases?

Answer 1

The particles become more crowded.

Question 2

How do we dilute solutions?

Answer 2

If we want to dilute a solution by a certain factor it will take up however many times that factor in volume.

Question 3

How would we make a solution ten times more dilute from 1cm^3?

Answer 3

• Starting with 1, the end result would be 10 because that is ten times the amount
• Take the original amount away from the end amount, 10 - 1 = 9
• So we would need to add 9cm^3 of water

Question 4

How do we convert cm^3 to dm^3 and vice versa?

Answer 4

• cm —> dm = /1000

- dm —> cm = X1000

Question 5

What is the calculation for concentration?

Answer 5

Concentration = moles / volume

Moles = concentration X volume

Volume = moles / concentration

Question 6

What would the number of moles be in a 0.1mol/dm^3 solution of 500cm^3?

Answer 6

• Units must always match so convert cm —> dm, 500/1000 = 0.5
• 0.5 X 0.1 = 0.05 moles

Question 7

What is GDA?

Answer 7

Guideline daily amount in foods.

Question 8

What are sodium ions essential for?

Answer 8

• Water balance

- Nerve response

Question 9

What can too much sodium ions do?

Answer 9

Cause high bp and heart disease.

Question 10

How do we calculate the sodium content from salt?

Answer 10

• NaCl = 23 + 35.5 = 58.5
• Therefore there are 23g of sodium per 58.5g of salt
• Therefore there is 1g of sodium in 58.5/23 = 2.5g of salt
• So the mass of salt is 2.5 times the mass of sodium