U6 CP Chem % Comp, MM, Hydrates

Front

What is the formula to calculate the number of moles from the number of atoms?

Back

Number of moles = Number of atoms / Avogadro's Number (6.02 x 10^23)

Front

How do you determine the molar mass of a compound?

Back

Add the atomic masses of all the atoms in the compound's formula.

Front

What is Avogadro's Number?

Back

6.02 x 10^23, the number of atoms or molecules in one mole of a substance.

Front

How do you calculate percent composition of a compound?

Back

Percent composition = (mass of element in 1 mole of compound / molar mass of compound) x 100%.

Front

What is a hydrate?

Back

A compound that contains water molecules within its crystal structure.

Front

How do you find the formula of a hydrate?

Back

Determine the mass of water lost and the mass of the anhydrous compound, then calculate the ratio of moles of water to moles of the anhydrous compound.

Front

What is the molar mass of potassium hydroxide (KOH)?

Back

56 g/mol (K=39, O=16, H=1) => 39 + 16 + 1 = 56.

Front

What is the percent composition of Cu2S?

Back

%Cu = 79.854%, %S = 20.145%.

Front

How many moles are in 3.01 x 10^22 atoms of magnesium?

Back

0.05 moles Mg.

Front

What is the formula for magnesium carbonate hydrate with 5 water molecules?

Back

MgCO3 · 5H2O.