Molar Mass
What units that you measure molar mass in?
grams (g)
1 mole of molecules/atoms/formula units is equal to ____ and is called _______ ________
6.02*1023, Avogadro's number
How many molecules is 36.04g H2O?
1.24*1024 molecules H2O
Define Empirical Formula
is the simplest/lowest whole-number ratio of the atoms in a compound.
What is the percent composition of NaCl?
39.34% Na
60.66% Cl
NaCl
57.44g
How many moles in 2.0g of He
0.5 mol
how many grams is 120L of CO2?
235.77g CO2
If you're given percent composition, what is the first step to finding empirical formula?
First, assume you have exactly 100 grams of the sample and convert the percents to grams.
What is the percent composition of CaSO4?
Ca: 29.44%
S: 23.55%
O: 47.01%
Al(NO3)3
212.98g
How many grams in 1.5 moles of CH4?
24.075g or 24.08g CH4
How many molecules are in 10.4L of NO?
2.80*1023 molecules NO
What is the empirical formula for a compound containing 38.8% carbon, 16.2% hydrogen, and 45.1% nitrogen?
CH5N
What is the percent composition of potassium permanganate?
K: 24.74%
Mn: 34.76%
O: 40.50%
Vanadium (V) oxide
181.88g
How many molecules are in 3.75 moles of water?
2.26*1024 molecules of water
how many grams are in 450mL of CO?
0.56g CO
What is the empirical formula of a compound containing 47.37% carbon, 10.59% hydrogen, and 42.04% oxygen?
C3H8O2
Percent Composition for the oxygen in calcium arsenate
O: 32.15%
Manganese (VII) arsenate
1137.26g
how many moles is 0.05L of helium gas at STP?
0.0022 moles He
How many atoms are in 875 mg of hydrogen gas?
5.22*1023 molecules of H2
An unknown compound is found to contain 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen with a molecular mass of 60.0 g/mol. What is the molecular formula of the unknown compound?
C2H4O2
what is the percent composition of glucose?
C: 40.00%
H: 6.71%
O:53.29%