Question

Correct calculation

A) How many moles of silver are in a 100. G sample?

B) Isoquinoline has the molecular formula C9H7N. Its molar mass in g/mol is:

c) Given the combustion of propane

C3H8 + 5O2 => 3CO2 + 4H2O

How many grams of oxygen are required to burn 8.8 grams of C3H8? (Molar masses in grams per mole- propane: 44.2; oxygen: 31.99; carbon dioxide: 44.01; water: 18.02)

Answer 1

A) moles of silver = mass of silver / molar mass of silver = 100 g / 108 g/mol = 0.926 moles

B) C9H7N

Molar mass = (9 x 12) + (7 x 1) + 14 = 129 g/mol

C)       C3H8   + 5O2    ----------------> 3CO2 + 4H2O

         1 mol        5 mol

          44.2 g     5 x32 g = 160 g

          8.8 g            ?

                   ? = (8.8 g/ 44.2 g ) x 160 g oxygen

                       = 31.85 g of oxygen

Therefore,

31.85 grams of oxygen are required to burn 8.8 grams of C3H8