Chemistry Topic 9/10

Created by: Sophie Russell
Created on: 18-02-14 20:24

T9- Define the empirical formula

It is the simplest formula that tells you the ratio of the different elements in the compound.

1 of 8

T9- What is the five step method to work out the empirical formula?

1) List all the elements in the compound. 2) underneath each, write their experimental mass or percentage. 3) Divide each by their Ar. 4)Turn into ratio. 5) rewrite formula.

2 of 8

T9- Define the molecular formula

It tells you the actual number of atoms of each element in one molecule.

3 of 8

T9- What is the method to work out the molecular formula?

1) Work out the mass of the empirical formula. 2) Divide the Mr by the empirical formula's mass. 3) This gives you the number of the empirical units. 4) Times the empirical formula by the number of empirical units.

4 of 8

T10- What is the method to calculate masses in reactions?

1)write the balanced equation. 2) work out the relative formula mass formulae of the relevant molecules. 3) DIVIDE TO GET, ONE MULTIPLY TO GET ALL.

5 of 8

T10- When you work out the masses in reactions, what does this give you?

THE THEORETICAL YIELD.

6 of 8

T10- What does percentage yield show?

It compares actual and theoretical yields.

7 of 8

T10- How do you work out the percentage yield?

actual yield/ theoretical yield x100

8 of 8

Other cards in this set

Card 2

Front

T9- What is the five step method to work out the empirical formula?

Back

1) List all the elements in the compound. 2) underneath each, write their experimental mass or percentage. 3) Divide each by their Ar. 4)Turn into ratio. 5) rewrite formula.