Calculations

Question 1

Whats Mr?

Answer 1

Relative Formula Mass - Atomic Masses added together

Question 2

Whats a mole of a substance?

Answer 2

The relative formula mass of a substance in grams

Question 3

How do you work out number of moles in a substance?

Answer 3

Total Mass / Mr

Question 4

How do you calculate % Mass of an element in a compound?

Answer 4

Ar x no. of atoms / Mr x 100

Question 5

Whats the layout of empirical formula?

Answer 5

1) List elements
2) Experimental Masses
3) Divide by Ar
4) Multiply by 10
5) Simplify

Question 6

How do you calculate masses in reactions?

Answer 6

1) Write balanced equation
2) Work out Mr
3) Divide for 1, Multiply for All

Question 7

How do you work out percentage yield?

Answer 7

Actual / Predicted x 100

Question 8

Why do you not get 100% yield?

Answer 8

1) Reaction is Reversible
2) Filtration
3) Unexpected Reactions

Question 9

What is sustainable development?

Answer 9

Ensuring that resources are preserved for future generations.

Question 10

What are the types of chromatography?

Answer 10

1) Paper Chromatography

2) Gas Chromatography

Question 11

How does Paper Chromatography work?

Answer 11

1) Extract colour from food sample by placing it in cup with solvent.
2) Put spot on pencil baseline on filter paper.
3) Place in beaker with solvent.
4) Solvent seeps up paper taking dyes with it.

Question 12

How does GS-Ms work?

Answer 12

1) Carrier Gas moves substance through substance.
2) Substances travel at different speeds and separate.
3) The time they take to reach the detector is the retention time.
4) The spectrometer detects the substance.

Question 13

Why is Gas Chromatography Better than Paper Chromatography?

Answer 13

1) Very Sensitive - Detect small amounts
2) Very Fast
3) Very Accurate

Question 14

What is Ar?

Answer 14

Relative atomic Mass - Mass Number