# Stoichiometric Calculations: Exercises and Solutions

### Exercise: Balance the following chemical reactions:

Exercise on Balancing Chemical Reactions

Check your answers here: Solution to the Exercise on Balancing Chemical Reactions

### Formula weight of a molecule

The summation of the atomic weights of all atoms In the chemical formula of the molecule.
Note: Formula weight calculated by this way is also known as "Molecular Formula Weight" or "Molecular Weight"

Question: Calculate the formula weight of HClO4
11.01H

1735.5Cl

816O

Solution: Molecular Weight = (1 × 1) + (1 × 35.5) + (4 × 16) = 100.5 amu

### Example: Calculate the % N in NH4NO3

816O

11.01H

714N

% N = (((# of atoms of the element) × (atomic weight of the element))/ (Formula weight of the compound))) × 100 =
= (2 × 14) / ((1 × 14) + (4 × 1) + (1 × 14) + (3 × 16)) = 35; which means that NH4NO3 contains 35% of N.

### Exercise: Calculate the formula weight of the following molecules

Exercise on Calculating the Formula Weight of Molecules

Check your answers here: Solution to the Exercise on Calculating the Formula Weight of Molecules

### Exercise: Mole & Molar Mass

Exercise on Mole & Molar Mass

Check your answers here: Solution to the Exercise on Mole & Molar Mass

Exercise on Number of Atoms and Moles

Check your answers here: Solution to the Exercise on Number of Atoms and Moles

Exercise on Finding Mass and Number of Moles

Check your answers here: Solution to the Exercise on Finding Mass and Number of Moles

Exercise on Mass Produced from Burning Butane

Check your answers here: Solution to the Exercise on Mass Produced from Burning Butane

Exercise on Finding the Limiting Reactant

Check your answers here: Solution to the Exercise on Finding the Limiting Reactant

Exercise on Finding Theoretical Yield

Check your answers here: Solution to the Exercise on Finding Theoretical Yield