In an experiment, 44 g of propane, c3hg, was burned producing 132 g of carbon dioxide and 72g of water. the mass of oxygen that was needed for the reaction was?

The law of conservation of mass states that mass can neither be created or destroyed, hence we expect product mass to equal reactant mass.

mass of propane + mass of oxygen = mass of carbon-dioxide + water

Using stochiometry, we first  write a balanced the equation

The ratio of propane to oxygen is 1:5, 1 mol propane reacts with 5 mol oxygen

First find the moles of propane using the mass of propane 44g and molecular mass of propane 44.1g/mol

The grams of oxygen would be, using molecular mass 32 g/mol

The answer rounded to 3 significant figures gives us .

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2