1) Elemental phosphorus burns in oxygen with an intensely hot flame, producing a brilliant light and clouds of the oxide product. These properties of the combustion of phosphorus have led to its being used in bombs and incendiary devices for warfare.

P₄(s) + 5O₂(g) → 2P₂O₅(s)

If 7.95 g of phosphorus is burned, what mass of oxygen does it combine with?

____g O2

2) In the "Chemistry in Focus" segment "Cars of the Future," the claim is made that the combustion of gasoline for some cars causes about 0.50 lb of CO₂ to be produced for each mile traveled. Estimate the gas mileage of a car that produces about 0.50 lb of CO₂ per mile traveled. Assume gasoline has a density of 0.75 g/mL and is 100% octane (C₈H₁₈). While this last part is not true, it is close enough for estimation. The reaction can be represented by the following unbalanced chemical equation:

C₈H₁₈+ O₂→ CO₂+ H₂O

____mi/gal

3) If common sugars are heated too strongly, they char as they decompose into carbon and water vapor. For example, if sucrose (table sugar) is heated, the reaction is

C₁₂H₂₂O₁₁(s) → 12C(s) + 11H₂O(g)

What mass of carbon is produced if 7.31 g of sucrose decomposes completely?

___g C