Practice Quiz CH. 6
How many moles of N₂O₄ are in 76.3 g N₂O₄? The molar mass of N₂O₄ is 92.02 g/mol.
0.829 moles
How many atoms of oxygen are contained in 47.6 g of Al₂(CO₃)₃? The molar mass of Al₂(CO₃)₃ is 233.99 g/mol.
1.10 x 10²⁴ O atoms
How many molecules of bromine liquid, Br₂, have a mass equal to 31.8 g?
1.20 x 10²³ molecules
How many atoms of krypton are in 2.50 mol of Kr gas?
1.51 x 10 ²⁴ atoms
What is the mass of 5.55 x 10²² formula units of calcium chloride, CaCl₂?
10.2 g
What is the mass percent of hydrogen in water?
11.2
What is the molar mass of aspirin, C₉H₈O₄?
180.17 g/mol
One mole of ammonium nitrate contains:
2 moles of nitrogen.
How many formula units of sodium sulfate are in 0.333 mol of Na₂SO₄?
2.00 x 10²³ formula units
How many moles of ammonia contain 1.51 x 10²⁴ NH₃ molecules?
2.51 mol
What is the mass (in kg) of 6.89 x 10²⁵ molecules of CO₂ is 44.01 g/mol.
5.04 kg
How many grams of carbon are present in 26.2 grams of H₂CO₃?
5.07 g
The formula for mustard gas used in chemical warfare is C₄H₈SCl₂ (159.09 g/mol). What is the percentage of hydrogen in the compound?
5.08%
Which of the following is the correct "set-up" for the problem "How many grams of S are present in 50.0 g of S₄N₄?"
50.0 g S₄N₄ x 1 mole of S₄N₄/ 184.32 g S₄N₄ x 4 mole S/ 1 mole S₄N₄ x 32.07g S/ 1 mole S
What is the mass of 3.30 x 10²³ atoms of silver, Ag?
59.1 g
How many atoms of cobalt are equal a mass of 58.93 g? (Refer to the Periodic Table)
6.022 x 10²³
How many sodium ions are contained in 99.6 mg of Na₂SO₃? The molar mass of Na₂SO₃ is 126.05 g/mol.
9.52 x 10²⁰ sodium ions
Fructose is a sugar found in fruit and honey. Calculate the empirical formula for fructose given its percent composition: 40% C, 6.72% H, 53.29% O.
CH₂O
If 1.216 g of cobalt metal reacts with 0.495 g of oxygen gas, what is the empirical formula of the cobalt oxide product?
Co₂O₃
Vitamin C is known chemically by the name ascorbic acid. Determine the empirical formula of ascorbic acid if it is composed of 40.92% carbon, 4.58% hydrogen, and 54.50% oxygen.
C₃H₄O₃
Lysine is used as a medicinal skin cream. What is the molecular formula if the empirical formula is C₃H₇NO, and the approximate molar mass is 146 g/mol?
C₆H₁₄N₂O₂
C₂H₆O₄ could be an empirical formula.
False
One mole of argon has more atoms in it than one mole of neon.
False
One mole of water contains 6.022 x 10²³ hydrogen atoms.
False
The correct formula for calculating mass percent of X in compound XY is: Mass of X in a sample of the compound/ Mass of Y in a sample of the compound = Mass % X
False
What is the term used for the amount of substance that contains 6.02 x 10²³ particles?
Mole
If 0.225 mol of tin combines with 0.450 mol of sulfur, what is the empirical formula of the tin sulfide product?
SnS₂
An empirical formula gives the smallest whole number ratio of each type of atom in a molecule.
True
Avogadro's Number is 6.022 x 10²³.
True
C₂H₃O₂ could be an empirical formula.
True
C₂H₆O₃ could be an empirical formula.
True
One mole of CO₂ gas contains 1 mole of carbon atoms and 2 moles of oxygen atoms.
True
One mole of water contains 16 grams of oxygen atoms.
True
Six grams of carbon contain 3.008 x 10 ²³ atoms.
True
The lighter the atom, the less mass in one mole of that atom.
True
Water is 11.2% hydrogen by mass.
True
The chemical formula CH₂O can be classified as:
empirical, possibly molecular.
What would the empirical formula be for the molecular compound C₆H₉O₄?
none of the above
