Unit 3

Question 1

whats the formula for relative atomic mass (Ar)

Answer 1

[(%1 x mass1) + (%2 x mass2)] / 100

Question 2

what is the Avogadro constant?

Answer 2

6.02 x 10^23

Question 3

what is 1 mole?

Answer 3

6.02 x 10^23

Question 4

whats the formula for the % purity of a substance?

Answer 4

(mass of pure substance / total mass) x 100

Question 5

whats the formula for the % yield?

Answer 5

(actual mass of product made (useful product)) / theoretical mass of product (could have been made) x 100

Question 6

whats the formula for the number of moles?

Answer 6

mass (g) / relative molecular mass (Mr/Ar)

Question 7

whats the formula for the number of atom molecules?

Answer 7

number of moles x avogadro constant

Question 8

whats the formula for the number of moles for gas?

Answer 8

volume of gas we have / 24

Question 9

whats the formula for the mass of gas?

Answer 9

number of moles (for gas) x Mr

Question 10

whats the definition of relative atomic mass (Ar)?

Answer 10

Relative atomic mass (Ar) as the average mass of the isotopes of an element compared to the 1/12th of the mass of an atom of 12C

Question 11

whats the gas test for hydrogen?

Answer 11

a lit splint combusts with a squeaky pop

Question 12

whats the gas test for oxygen?

Answer 12

oxygen will relight a glowing splint

Question 13

whats the gas test for carbon dioxide?

Answer 13

bubble carbon dioxide into lime water, lime water goes from colourless to cloudy / carbon dioxide turns limewater cloudy

Question 14

how do you find the moles of each atom?

Answer 14

number of how many element’s there are x number of moles