calculating the percentage yield for a reaction

Question 1

Calculate the mass of magnesium sulfate that could be produced from 48g of magnesium. assume that the sulphuric acid is unlimited.
Ar Mg= 24
Ar S= 32
Ar O = 16

Answer 1

first calculate number of moles of magnesium = mass(g)/RAM Ar
48g/24 Ar =2
2 moles of magnesium can produce 2 moles of magnesium sulphate
calculating mass of magnesium sulphate
mass(g)=No. of moles x RFM Mr
mass(g)= 2 x 120
= 240g
100% YIELD
for this to happen every single atom of magnesium must react to form the product magnesium sulphate

Question 2

why is it not always possible to achieve 100% yield in a chemical reaction

Answer 2

some product may be lost when it is separated from the reaction mixture
some reactants may react in different ways to the expected reaction so we do not get the product we expect
Reversible reactions may not go to completion

Question 3

a scientist reacted 48g of magnesium and produced 150g of magnesium sulfate. Calculate the percentage yield.

Answer 3

percentage yield = mass of product made / maximum theoretical mass of product
then multiply x by 100

150g

Question 4

what is the equation for percentage yield

Ar Mg= 24
Ar S= 32
Ar O = 16

Answer 4

62.5%
percentage yield =
mass of product made/max theoretical mass of product 
x 100
% yield = 150g/240 x 100 = 62.5%

Question 5

percentage yield can’t be greater than…

Answer 5

100%
if it is
it would mean that we have created atoms which is impossible
u have done the equation wrong and switched the division

Question 6

A scientist reacted 130g of zinc with unlimited copper sulphate. They produced 25.4g of copper. Calculate the percentage yield
Ar Zn=65
Ar Cu=63.5
Zn + CuSO4 -> Cu + ZnSO4

Answer 6

number of moles =

mass(g)/RAM Ar