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WorksheetsReg.Chem- 70% Summative: Mole, % Comp, EF, & MF
Total questions: 20
Worksheet time: 41mins
Calculate the molar mass of Magnesium Phosphate
(Hint: Your answer should have 4 sig figs and NO UNITS)
How many grams are in 3.35 moles Cu₂CO₃?
0.0179 moles
627 grams
627 moles
0.0179 grams
How many CO₂ molecules are present in 12.47 L CO₂? (Remember: Pay attention to sig figs and units)
3.35 x 1023 molecules
3.352 x 1023 molecules
3.352 x 1025 molecules
3.352 x 1023 grams
What is the percentage of hydrogen in NH₄C₂H₃O₂?
9.17%
1.30%
5.52%
13.0%.
Find the empirical formula of a compound that contains 53.70% iron and 46.30% sulfur.
FeS
Fe2S3
FeS2
Fe3S4
A sample containing only copper and sulfur has a total mass of 75.0 g. The mass of the copper is
49.87 g. What is the empirical formula?
(a)
A compound has an empirical formula of CH3. If the molar mass of the compound is 30.08 g/mol, what is the molecular formula?
(a)
Determine the molecular formula of a compound that is 64.27% carbon, 7.19% hydrogen, and 28.54% oxygen, and has a molar mass of 168.19 g/mol.
C3H4O
C9H12O3
C9H12O
C9H9O3
Find the percent composition of each element in the compound Copper (I) Sulfide. (Check box ALL the correct answers)
S= 32.01%
Cu= 79.85%
Cu= 35.95%
S= 20.15%
S= 26.17%
Find the empirical formula if you are given the following percentages: 40.05% S and 59.95% O.
(S = 32.07 g/mol, O = 16.00 g/mol)
The chemical symbol of this compound is (a)
What is the molecular formula if the empirical formula is CH2O and the molecular molar mass is 180.18?
(C = 12.01 g/mol, H = 1.01 g/mol, O = 16.00 g/mol)
How many molecules are present in 135 g of Teflon: C2F4
6.13 x 1023 molecules
5.13 x 1023 molecules
8.13 x 10 23 molecules
9.13 x 1023 molecules
Percent composition tells you:
The number of atoms in a compound
The percent by mass of each element in a compound
The ratio of moles of reactants
The number of molecules in a sample
If a compound's empirical and molecular formulas are the same, what does this mean?
The compound is ionic
The compound is covalent
The simplest ratio represents the actual molecule
The molecular mass is doubled
What is the empirical formula of a compound that is 92.3% carbon and 7.7% hydrogen?
CH
CH2
CH3
C2H2
What is the empirical formula for a compound that is 54.48% carbon, 13.75% hydrogen, and 31.77 % nitrogen?
C (a) H (b) N
Rank the elements from lowest % = #1 to highest %= #4 that make up caffeine: C8H10N4O2
% of H
% of O
% of N
% of C
What is the mass of 0.20 moles of Ga2(SO3)3?
(Hint: The answer should have proper sig figs and NO UNITS)
