The Mole Concept
Avogadro's constant/number is equal to
6.022 x 1023
The volume occupied by 3 moles of N2 gas at STP
67.2 L
Formula for percent composition
% = (part/whole) x 100
True or False: C2H4 is an empirical formula
False, empirical formulas are the simplest whole number ratio
The molecular formula of a compound is the _________ formula
actual
The mass of one mole of a substance is called
Molar Mass
0.5 moles (0.499)
Percent of carbon in CO2
27.3%
Do these two compounds have the same empirical formulas: C2H4O2 and C6H12O6
yes - CH2O
A compound with a molar mass of 375 g has the empirical formula of P3O2. What is the molecular formula?
P9O6
The volume occupied by 1 mole of any gas at STP
22.4 L
The mass in grams of 2 moles of CO2
88 g
Which has the greatest percent of S?
a. SrS
b. BaS
c. CaS
d.MgS
D. MgS - 56.9%
The rhyme for the steps to find empirical formulas
percent to mass, mass to mole, divide by small, multiply til whole
A compound has a mass of 90 g/mol and it's empirical formula is CH2O, what is its molecular formula?
C3H6O3
The number of moles of oxygen present in 1 mole of P2O5
5 moles of O
The mass of 3.5 x 1024 formula units of NaCl
339.7 g
What is the percentage of water in CuSO4 * 5 H2O
36%
The empirical formula of a compound that is 50% sulfur and 50% oxygen
SO2
The empirical formula of a compound is C3H5O2. The molecular molar mass is 146.16 g/mol. What is the molecular formula?
C6H10O4
The molar mass of the compound Al2(CO3)3
233.99 g/mol
The number of molecules present in 73 g of nitrogen dioxide
9.55 x 1023 molecules
42%
The empirical formula of a compound that is 40% carbon, 6.7% hydrogen, and 53.5% oxygen
CH2O
A compound is 49% C, 2.72% H, and 48.3% Cl. It's molecular mass is 147 g/mol. What is its molecular formula?
C6H4Cl2