Star-nosed mole
The mass of one mole of a substance is called its
molar mass
Avogadro's number tells the number _______ in one mole of a compound and the number of ________ in one mole of an element.
molecules, atoms
What is the unit for molar mass?
g/mol
What is the volume of one mole of helium gas at STP?
22.4 L
Which is heavier, one mole of calcium or one mole of cesium? Which contains more particles?
cesium is heavier; they contain the same number of particles
Find the molar mass of iron (III) nitrate.
241.88 g/mol
What is the molar mass of aluminum sulfate?
342.17 g/mol
What does STP stand for? Why must a gas be at STP in order to convert between volume and moles?
standard temperature and pressure; temperature and pressure both affect the volume of a gas
0.65 moles of an element have a mass of 130 g. What is the element?
Mercury
Determine the molar mass of dinitrogen pentoxide.
108.02 g/mol
Sodium sulfate is commonly used in soaps and detergents. What is the percent composition of each element in sodium sulfate?
% Na = 32%, %S = 23%, %O = 45%
Ethylene glycol (C2H6O2) is the main ingredient in antifreeze. What is the percent composition of each element in ethylene glycol?
%C = 39%, %H = 10%, %O = 52%
1.4 moles of an element have a mass of 37.8 g. What is the identity of the element?
Aluminum
Propane is the gas commonly used for cooking on outdoor grills. A sample of propane contains 36g of carbon and 8g of hydrogen. What is the percent composition of each element in the compound?
%C = 82%, %H = 18%
192g of a sulfur-oxygen compound contains 64g of sulfur.
What is the percent composition of each element in the compound?
%S = 33%, %O = 67%
For your birthday, you receive a helium balloon with a volume of 4.00 L at STP. What is the mass of the helium?
0.71 g
A teaspoon of table sugar, or sucrose (C12H22O11), has a mass of 7.5 g. How many molecules of sucrose are in a teaspoon?
1.32 x 1022 molecules
How many oxygen atoms are in a 35 g sample of oxygen gas (O2)?
1.32 x 1024 atoms O
How many molecules of ammonia (NH3) are in 40.0 g?
1.41 x 1024 molecules
What is the volume of 85.5 g of carbon monoxide at STP?
68.38 L
**Bonus question - 2x points!!**
A glass of iced tea contains 320 g water and 22.5 g sugar (C12H22O11). Calculate the total number of hydrogen atoms.
2.23 x 1025 atoms H
Find the mass in kg of 3.50 x 1025 molecules of chlorine gas.
4.12 kg
How many molecules of acetaminophen (C8H9NO2) are there in a 500 mg tablet?
1.99 x 1021 molecules
An average sized room has a volume of 38230 L. Calculate the number of atoms of nitrogen in the air if air is 78% nitrogen gas.
1.60 x 1027 atoms N
One serving of coffee contains about 95 mg of caffeine (C8H10N4O2). How many atoms of nitrogen are in the caffeine of one cup of coffee?
1.18 x 1021 atoms N