Chem IA
Moles Formative Quiz Answer Key
_A_1. How many atoms of neon (Ne) are in a 1452.96 moles sample of neon?
A. 8.7497 x 1026
B. 8749.72 x 1023
C. 87.49 x1027
D. 8.749 x1027
_D_2. Consider a 20 g sample of silver (Ag) metal and a 20 g sample of another “mystery” metal.
You are told that there are exactly four times as many atoms of the “mystery” metal as of silver
metal. Identify the “mystery” metal
A. Fe
B. Li
C. Pt
D. Al
_C_3. The molar mass of calcium nitrate, Ca(NO3)2 is:
A. 102.09 g/mol
B. 70.09 g/mol
C. 164.1 g/mol
D. 100.1 g/mol
_A_4. A single molecule of a particular compound has a mass of 4.65 X 10-23g. Which of the
following could be this compound?
A. CO
B. H2O
C. S2
D. NH3
_B_5. What is the percent by mass of carbon in table sugar (C12H22O11)?
A. 27.80%
B. 42.10%
C. 56.69%
D.71.38%
_B_6. Which of the following compounds have the same empirical formulas?
A. H2O and H2O2
B. N2O4 and NO2
C. CO and CO2
D. CH4 and C2H6
_C_7. The percent by mass of nitrogen is 46.7% for a species containing only nitrogen and oxygen.
Which of the following could be this species?
A. N2O5
B. NO2
C. NO
D. N2O
_D_8. A compound consisting of carbon, hydrogen, and oxygen is found to contain 40.00% carbon
by mass and 6.71% hydrogen by mass. A 0.0500mol sample of the compound has a mass of 9.00 g
Determine the molecular formula for the compound.
A. C8H16O4
B. C6H14O6
C. C6HO8
D. C6H12O6
_C_9. An oxide with the formula MO2 is 40.1% oxygen by mass. Determine the identity of M.
A. Cadmium
B. Calcium
C. Titanium
D. Magnesium
_B_10. How many moles of CO2 are present in 220 mg?
A. 5 moles
B. 0.005 mole
C.5000 moles
D.10 moles
_C_11. What is the percent water in hydrated calcium chloride...CaCl2·2H2O?
A. 66.67%
B. 32.47%
C. 24.51%
D. 2.26%
_C_12. What is the molecular formula for a compound that is 46.16% carbon, 5.16% hydrogen and
48.68% fluorine if the molar mass of this compound is 156.12 g?
A. C3H4F2
B. C5H10F5
C.C6H8F4
D. C6H6F3
_C_13. When 0.684 g of an organic compound containing only C, H, and O was burned in oxygen
1.312g CO2 and 0.805g H2O were obtained. What it the empirical formula?
A. CH3O
B. CH5O6
C. C2H6O
D. CH4
_D_14. One mole of (NH4)2HPO4 contains _?_ hydrogen atoms.
A. 7 x6.022 x1023 B. 8 x6.022 x1023 C. 6 x6.022 x1023
D. 9 x6.022 x1023
_D_15. A certain glucose solution weighing 115 g has a density of 1.23 g/cm3. Determine the volume
of this solution in cm3.
A. 0.0107 cm3
B. 114 cm3
C. 116 cm3
D. 93.5 cm3
_A_16. How many grams are there in 2.1 moles of sodium?
A. 48.3 grams
B. 0.0913 grams
C. 11.0 grams
D. None of these
_B_17. How many molecules are there in 45 grams of aluminum trifluoride?
A. 2.28 x 1027 molecules
C. 1.12 x 1024 molecules
23
B. 3.23 x 10 molecules
D. None of these is correct
_C_18. Lead (III) chloride reacts with calcium hydroxide to form calcium chloride and lead (III)
hydroxide. What are the coefficients for this reaction?
A. 3, 2, 2, 3
B. 2, 3, 2, 3
C. 2, 3, 3, 2
D. None of these
_B_19. At STP 14.0g of CH2 has a volume of 2.24 L. What is the molecular mass of this compound?
A. 42 g
B. 140 g
C. 14 g
D. None of the above
_B_20. If all of the oxygen from .01 moles of glucose C6H12O6 is filled in a balloon, what will the
volume be at SATP?
Note: the molar mass of glucose is 180.16g
A. 14.88
B. 0.744
C. 2.6784
D. 267.84
_D_21. A 2.500g sample of uranium was heated in the air. The resulting oxide weighed 2.949 g.
Determine the empirical formula of the oxide.
A. U3O5
B. U2O5
C. U2O3
D. U3O8
_C_22. If 11.273g of Z react with 4.8357g of oxygen to make a compound Z2O5, what element could
Z be?
A. Fe
B. Cu
C. Nb
D. Mn
The Dupont Chemical Company first manufactured nylon in 1930s. Nylon is composed of very long
chains of carbon and hydrogen atoms bonded together, with oxygen and nitrogen atoms bonded
periodically throughout the chain.
_D_23. If nylon 6 has a formula C6H11ON and nylon 11 has a formula C11H21ON, which of the
following will not be true?
A. Molar mass of nylon 113. 2g/ mol
B. Molar mass of nylon -11 is 183.3 g/mol
C. The difference between the two types of Nylon is 70.1 g/mol
D. They have the same empirical formula
_C_24. If 2.68 g of hydrated sodium sulfate, Na2SO4·nH2O, on heating produces 1.26 g of water,
what is the empirical formula of this compound?
A. Na2SO4·H2O
C. Na2SO4·7H2O
B. 2Na2SO4·H2O
D. 9Na2SO4·8H2O