Total number of atoms = 7
Total number of H atom = 5
% of H in ammonium hydroxide = 5/7 ×100 = 71.4 %
The molarity of a 27%(v/v) aqueous ethanol solution is 4.63 M
calculation
convert 27%(v/v) to fraction = 27ml/100 ml
use density to convert 27ml to grams = 27 ml x0.79 g/ml = 21.33 g
find the number of moles of C2H6O
moles = mass/molar mass of C2H6O(46.07 g/mol)
moles is therefore = 21.33 g /46.07 g/mol =0.463 moles
find the molarity = moles /volume in liters
volume in liter = 100 ml/1000 = 0.1 L
molarity is therefore = 0.463 mole/0.1 L = 4.63 M
Answer: 0.45 moles of 
will be produced from 0.15 moles of propanol.
Explanation:
The balanced chemical reaction is:
is the limiting reagent as it limits the formation of product and 
is the excess reagent.
According to stoichiometry :
2 moles of produces = 6 moles of
Thus 0.15 moles of 
will produce=
of
Thus 0.45 moles of will be produced from 0.15 moles of propanol.
Explanation:
3Ca(s) + 2AlCl3(aq) -> 3CaCl2(aq) + 2Al(s)
According to the question, Ca is the limiting reactant.
Therefore, we equate Ca to Aluminium which is the product whose mass we want to find
Molar mass of Ca- 40g/mol
". ". of Al- 27g/mol
3Ca --> 2Al
3×40 --> 2×27
9.2 --> x
x = 9.2×2×27= 496.8÷120=4.14
