Unit 10 BR #3: Mole Conversions and Ratios

Front

What is a mole in chemistry?

Back

A mole is a unit of measurement used to express the amount of a substance. It is defined as the amount of substance that contains as many entities (atoms, molecules, etc.) as there are in 12 grams of carbon-12.

Front

How do you convert grams to moles?

Back

To convert grams to moles, divide the mass of the substance (in grams) by its molar mass (in grams per mole). Formula: Moles = Mass (g) / Molar Mass (g/mol).

Front

What is the molar mass of water (H2O)?

Back

The molar mass of water is approximately 18.02 g/mol.

Front

What is the relationship between moles and molecules?

Back

1 mole of any substance contains approximately 6.022 x 10^23 molecules (Avogadro's number).

Front

How many moles are in 36 grams of water?

Back

To find the number of moles in 36 grams of water, divide 36 g by the molar mass of water (18.02 g/mol): 36 g / 18.02 g/mol = 2 moles.

Front

What is a conversion factor in mole calculations?

Back

A conversion factor is a ratio that expresses how many of one unit are equal to another unit, used to convert between different units of measurement.

Front

How do you convert moles of one substance to moles of another in a chemical reaction?

Back

Use the coefficients from the balanced chemical equation to set up a ratio for the conversion.

Front

What is the balanced equation for the combustion of methane (CH4)?

Back

The balanced equation is: CH4 + 2 O2 → CO2 + 2 H2O.

Front

If you have 3 moles of CO2, how many moles of O2 are needed for complete combustion of 1 mole of CH4?

Back

According to the balanced equation, 1 mole of CH4 requires 2 moles of O2. Therefore, for 3 moles of CO2 produced, 6 moles of O2 are needed.

Front

What is the significance of stoichiometry in mole conversions?

Back

Stoichiometry allows chemists to predict the quantities of reactants and products involved in a chemical reaction based on the balanced equation.