Balancing, Reactions, Percent Composition, and Empirical Formula

Front

What is Molarity?

Back

Molarity is a measure of concentration, defined as the number of moles of solute per liter of solution (mol/L).

Front

What is the significance of polarity in water molecules?

Back

Polarity in water molecules allows them to interact with various substances, making water an excellent solvent due to the partial positive and negative charges.

Front

How do you calculate the empirical formula from percent composition?

Back

Convert the percentages to grams, divide by the molar mass of each element to find moles, and then divide by the smallest number of moles to find the simplest ratio.

Front

What is the empirical formula of a compound with 42.07% Na, 18.89% P, and 39.04% O?

Back

Na3PO4.

Front

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

Back

Multiply the subscripts in the empirical formula by a whole number that makes the molar mass equal to the given molecular molar mass.

Front

What is the molecular formula if the empirical formula is CH2O and the molecular molar mass is 180.18?

Back

C6H12O6.

Front

How do you calculate the number of moles from volume and molarity?

Back

Moles = Molarity (mol/L) × Volume (L).

Front

If you have 0.045 L of 0.465 M potassium bromide, how many moles are present?

Back

0.0209 mol.

Front

What is the formula for calculating percent composition?

Back

Percent Composition = (mass of element in the compound / total mass of the compound) × 100.

Front

What is the difference between empirical and molecular formulas?

Back

The empirical formula shows the simplest whole-number ratio of elements, while the molecular formula shows the actual number of atoms of each element in a molecule.