MIXED MOLE CONVERSIONS
Use the following conversions factors to convert the given quantity into the desired unit.
1 mole= 22.4 Liters of gas at STP
1 mole= 6.02 x 1023 representative particles
1 mole = molar mass (sum of the mass of all the atoms within the compounds—masses for each element
can be found on periodic table)
1. a.) How many grams are there in 1.5 x 1025 molecules of CO2?
Given molecules—convert molecules to moles then moles to grams  1100 g
b.) What volume would the 1.5 x 1025 molecules of CO2 occupy at STP??
Given molecules—convert molecules to moles then moles to volume (liters)  560 L
2. a.) A sample of NH3 gas occupies 75.0 liters at STP. How many molecules is this?
Given liters—convert liters to moles then moles to molecules 2.02 x 1024 molecules
b.) What is the mass of the 75.0 liter sample of NH3?
Given liters—convert liters to moles then moles to mass (grams)  57.1 g
3. a.) How many atoms are there in 1.3 x 1022 molecules of NO2?
Given molecules—convert molecules to atoms  3.9 x 1022 atoms
b.) What is the mass of 1.3 x 1022 molecules of NO2?
Given molecules—convert molecules to moles then moles to mass (grams)  0.99 g
4. a.) A 5.0 gram sample of O2 is in a container at STP. What volume is the container?
Given grams—convert grams to moles then moles to volume (liters)  3.5 L
b.) How many molecules of oxygen is this 5.0 gram sample?
Given grams—convert grams to moles then moles to molecules  9.4 x 1022 molecules
5. a.) A sample of NH3 gas at STP occupies 10 liters. What is the mass of this sample?
Given liters—convert liters to moles then moles to mass (grams)  7.6 g
b.) How many atoms are in the 10 liter sample of NH3?
Given liters – convert liters to moles then moles to molecules then molecules to atoms  1.1 x 1024 atoms