Unit 6-Review The Mole

Front

What is the molar volume of a gas at STP?

Back

22.4 liters per mole.

Front

How do you calculate the number of moles from volume at STP?

Back

Number of moles = Volume (L) / 22.4 L/mole.

Front

What is an empirical formula?

Back

The simplest whole-number ratio of atoms in a compound.

Front

What is the empirical formula of C2H4?

Back

CH2.

Front

How do you find the percent by mass of an element in a compound?

Back

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

Front

What is the percent by mass of oxygen in MgO?

Back

40%.

Front

What is the percent by mass of potassium in KCl?

Back

52.7%.

Front

How many moles are in 250 liters of N2 gas at STP?

Back

11.16 moles.

Front

What is the volume of 2.5 moles of helium gas at STP?

Back

56 liters.

Front

What is the formula to convert moles to grams?

Back

Grams = moles x molar mass.