Chemistry

Question 1

how to calculate relative atomic mass?

Answer 1

relative atomic mass (Mr) = average mass / 1200

Question 2

How to calculate molarity?

Answer 2

molarity (M) = moles of solute / litre of solution

Question 3

How to find percentage yield?

Answer 3

(actual yield / theoretical yield) X 100

Question 4

how to calculate number of moles?

Answer 4

number of moles = mass in grams / Mr of element or compound

Question 5

how to find the percentage mass of an element?

Answer 5

percentage mass of an element = Ar X number of atoms / Mr of compound X 100

Question 6

how to calculate volume of gas?

Answer 6

volume of gas = mass / Mr X 24

Question 7

how to calculate concentration?

Answer 7

mass of solute / volume of solvent

Question 8

how to calculate concentration?

Answer 8

concentration = number of moles in solute / volume of solvent

Question 9

What is the mass number made of?

Answer 9

Mass number = Number of protons + Number of neutrons

Question 10

What is Avogadro’s number?

Answer 10

6.02 X 10 ^23

Question 11

how to calculate moles?

Answer 11

moles = mass / Mr

Question 12

how to find atom economy?

Answer 12

Mr of desired product / sum of Mr from all reactants X 100

Question 13

how to calculate energy change?

Answer 13

Energy change in a reaction = (total energy needed to break the bonds in reactants) - (total energy released when bonds in the products are formed)

Question 14

how to find the Rf in chromotography?

Answer 14

Rf = distance moved by substance / distance moved by solvent

Question 15

how to find mean rate of reaction?

Answer 15

mean rate of reaction = quantity of reactant used / time taken

Question 16

how to find mean rate of reaction?

Answer 16

mean rate of reaction = quantity of product formed / time taken