Formulas

Question 1

How do u find the empirical formula?

Answer 1

1. Work out number of moles (g/% over Ar)
2. divide each by smallest
3. The numbers rounded up = the empirical formula

Question 2

How do u calculate the molecular formula

Answer 2

1. Calculate the Mr of the empirical formula

2. Divide the Mr of the compound by the Mr of the empirical formula

Question 3

How many particles in a mole?

Answer 3

6.03x10 -23

Question 4

How do u find the moles

Answer 4

Mass/ Ar

Question 5

How do calculate moles from volume (DM3)

Answer 5

Moles = volume (dm3)
————–
24

Question 6

How do u work out the moles from a volume (CM3)

Answer 6

Moles = volume (cm3)
—————
2400

Question 7

What reasons are there for why the percentage yield isn’t 100?

Answer 7

• reaction isn’t reversible

- impure products

Question 8

Why would a bar chart be used?

Answer 8

If the independent variable is categoric

Question 9

Why would a line graph be used

Answer 9

If the independent variable is continuous

Question 10

How many coulombs in a faraday?

Answer 10

96,500 coulombs

Question 11

How many faradays are there in a mole

Answer 11

1

Question 12

How many coulombs in one mole

Answer 12

96,500 coulombs

Question 13

How do you work out the coulombs

Answer 13

Q=I/T

Question 14

How would you find the mass of a substance when given only the current and time?

Answer 14

• Q=I/T
• faradays=Q/96500
• mass=faradays x Ar