<span>% by mass = mass solute x 100 / mass solution
45.5 % = mass solute NaF x 100 / 34.2
mass solute NaF = 34.2 x 45.5 /100=15.6 g
molae solute NaF = 15.6 g ( 1 mol / 41.9887 g)= 0.372</span>
Incomplete combustion<span> occurs when the supply of air or oxygen is poor. Water is still </span>produced<span>, but </span>carbon<span> monoxide and </span>carbon<span> are </span>produced<span> instead of </span>carbon dioxide<span>. The </span>carbon<span> is released as soot. </span>Carbon<span> monoxide is a poisonous gas, which is one reason why </span>complete combustion<span> is preferred to </span>incomplete combustion<span>.</span>
Answer: Theoretical mass of sodium sulphate (
) is 514.118 grams.
Explanation: For a given reaction,

As NaOH is used in excess, therefore it is an excess reagent and
is a limiting reagent as the quantity of the product will depend on it.
We are given 355 grams of
.
Molar mass of
= 98.079 g/mol
Molar mass of
= 142.04 g/mol
1 mole of
is producing 1 mole of
, so
98.079 g/mol of
will produce 142.04 g/mol of
355 grams of
will produce =
of 
Mass of
= 514.118 grams
His the answer I hope it helps