1 STEP
2 STEP
MOLECULAR VS. EMPIRICAL
% BY MASS & MOLAR MASS
Important Vocab
Random Chemistry Trivia
100
How many molecules are in 1.5 moles of CO2?
9.0 x 1023 molecules of CO2
100
Ionic compounds are between a what and what?
metal and nonmetal
100
Which formula, molecular or empirical, is the simplest version a formula?
Empirical Formula
100
What is the molar mass of CaO?
56.08 g/mol CaO
100
The scientist who came up with the mole?
Avogadro
100
True or false?
Sterling silver is pure silver?
False. It contains up to 7.5% copper.
200
If the question is asking for moles, will that be a large or small number?
small
200
What mass would there be in 4.32x1023 atoms of Krypton?
0.718 moles Kr (1st step)
60.14 g (2nd step)
200
What is the empirical formula for the following: C4H8
CH2
200
What is the molar mass of (NH4)2SO4?
132.17 g/mol (NH4)2SO4
200
unit for mass
grams
200
What is this?
Burette
300
How many moles are equal to 89.23g of calcium oxide, CaO?
1.591 mol CaO
300
How many molecules are in 13.5g of sulfur dioxide, SO2?
1.27 x 1023 molecules of SO2
300
True/False: You can have multiple molecular formulas and only one empirical formula.
True
300
What is the % Mg in MgO?
60.31% Mg
300
the number of particles in a mole?
6.02 x 1023
300
What is the only letter that doesn't appear in the periodic table?
J
400
How many grams are equal to 0.11 moles of copper (I) chromate, Cu2(CrO4)?
27 g Cu2(CrO4)
400
If I have 8 x 1023 atoms of oxygen, what mass of SO2 must I have?
0.66 moles
42.56g SO2
400
What is the empirical formula for a compound that is 7.70% carbon and 92.30% chlorine?
CCl4
double your points and tell me what the name of this molecule is!
400
What is the % of hydrogen in (NH4)2(SO4)?
6.11% H
400
units for molar mass
g/mol
400
Which is denser, water or ice?
Water, as ice floats.
500
What mass would 2.25 moles of Ne gas be?
45.405g Ne
500
If I have 9.55g of He, how many particles do I have?
2.3875 moles
1.43 x 1024 particles of He
500
Calculate the molecular formula of a compound with the empirical formula C2H2O and a molar mass of 126.12 g/mol.
C6H6O3
500
The diatomic molecule of an element Z has a mass of 6.31 x 10-23g. What is the atomic mass of the element Z?
mass of 1 atom of Z = 0.5 x 6.31 x 10-23 g
= 3.16 x 10-23 g.
atomic mass = mass of elemental atom x A
= 3.16 x 10-23 x 6.02 x 1023
= 19.0 g/mol
500
Draw the NAM triangle
500
In Australia we use Celsius (oC) and America uses (oF), what other measurement is used all over the world to measure temperature?
Kelvin (K)