Percent by Mass & Determining Chemical Formulas

What is the percent by mass of Oxygen in water? H₂O.

What is the percent by mass of Carbon in sugar C₁₂H₂₂O₁₁ ?

What is the percent by mass of Hydrogen in sugar C₁₂H₂₂O₁₁?

What would the percent by mass be of Oxygen in a compound that has a formula of C₁₀H₁₈O ?

The formula of a compound having the smallest whole-number ratio of atoms in the compound is called ____?

What is the empirical Formula of an unknown compound that is 18.8% sodium, 29.0% chlorine and 52.2% Oxygen?

Hint *(Don't forget to assume a 100 gram sample)

What is the empirical formula for a compound that is 40% Carbon, 6.70% Hydrogen and 53.3% oxygen?

Hint*(remember to assume 100 g sample)

Indigo the dye used to color blue jeans is prepared using sodium amide. Sodium amid contains the following percentages by mass of the following elements: 5.17% Hydrogen, 35.9% Nitrogen and 58.9% sodium. What is the empirical formula for Sodium amide?

The reaction of iron III oxide and aluminum is called the thermite reaction because of intense heat and is used to weld railroad tracks. Below is the balanced equation:

Fe₂O₃ (s) + 2Al (s) --> Al₂O₃ (s) + 2Fe (l)

If 20.0g of each reactant are used, which is the limiting reactant? (runs out first)

Hint(Do molar mass calculation to Fe for Theoretical Yield for both and compare the two.

A manufacturer advertises a new synthesis reaction for methane with a percent yield of 110%. Comment on this claim.