C4 calculations

Question 1

relative formula mass (Mr)

Answer 1

adding atomic masses of elements

big number

Question 2

realtive atomic mass

Answer 2

average mass of all different isotopes of an element compared to a carbon 12

Question 3

formula of relative atomic mass

Answer 3

total mass of all atoms/total number of atoms

Question 4

formula of relative atomic mass

Answer 4

total mass of all atoms/total number of atoms

Question 5

percentage of an element in a compound by mass by mass

% by mass of Fe in Fe03

Answer 5

100 x 2(56)/160=70%

100 x R/Mr

Question 6

mass

Answer 6

Mr x mol

Question 7

percentage yield

Answer 7

actual mass of product/max theoretical mass x 100

Question 8

factors affecting percentage yield

Answer 8

reaction may be reversible
reactants may be not pure
some of the reactant may be lost in handling or left in apparatus
“””””””””””””””””””””””””””””””””””””””"”during its separatioon from reaction mixture

Question 9

atom economy

Answer 9

relative formula mass of desired product/sum of the relative fformula masses of reactants x 100

Question 10

concentration (mol/dm3)

Answer 10

amount of substance/ volume

Question 11

concentration (g/dm3)

Answer 11

mass/volume