Stoichiometry Exam

Front

What is stoichiometry?

Back

Stoichiometry is the branch of chemistry that deals with the calculation of reactants and products in chemical reactions based on the conservation of mass.

Front

What is a mole in chemistry?

Back

A mole is a unit of measurement used to express amounts of a chemical substance, defined as exactly 6.022 x 10²³ particles (atoms, molecules, ions, etc.).

Front

How do you calculate the number of moles from mass?

Back

Number of moles = mass (g) / molar mass (g/mol).

Front

What is the mole ratio in a chemical reaction?

Back

The mole ratio is the ratio of moles of one substance to the moles of another substance in a balanced chemical equation.

Front

What is the empirical formula?

Back

The empirical formula is the simplest whole-number ratio of atoms of each element in a compound.

Front

How do you determine the empirical formula from molecular formula C2H4?

Back

Divide the subscripts by their greatest common divisor: C2H4 → CH2.

Front

What is the balanced equation for the reaction of nitrogen and hydrogen to form ammonia?

Back

N2 + 3H2 → 2NH3.

Front

If 2 moles of nitrogen react, how many moles of hydrogen are needed?

Back

6 moles of hydrogen are needed.

Front

In the reaction 2 Al + 3 CuCl2 → 3 Cu + 2 AlCl3, how many moles of CuCl2 are needed to produce 12 moles of AlCl3?

Back

18 moles of CuCl2 are needed.

Front

What is the mole ratio of AgNO3 to Cu in the reaction 2AgNO3 + _Cu → _Cu(NO3)2 + 2Ag?

Back

The mole ratio is 2:1.