Calculating Molar Mass quiz #4 Flashcards
Calculating Molar Mass quiz #4
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How many Br atoms are in 2.50 g of Br?
Moles = 2.50 g / 79.90 g/mol = 0.0313 mol; atoms = 0.0313 × 6.022 × 10^23 ≈ 1.88 × 10^22. What is the purpose of determining the formula mass of a compound?
Formula mass helps calculate the mass of a compound and perform stoichiometric calculations. What is the molar mass of CaCl2?
The molar mass of CaCl2 is 110.98 g/mol. What is the molecular mass of acetic acid?
The molecular mass of acetic acid is 60.05 g/mol. What is the formula mass of Al2(SO4)3?
The formula mass of Al2(SO4)3 is 342.15 amu. What is the molar mass of pure tin (Sn)?
The molar mass of tin is 118.71 g/mol. What is the molar mass of hydrogen gas (H2)?
The molar mass of hydrogen gas is 2.016 g/mol. What is the molar mass of SO2?
The molar mass of SO2 is 64.07 g/mol. What is the molar mass of CH3COOH?
The molar mass of CH3COOH is 60.05 g/mol. What is the molar mass of barium hydroxide (Ba(OH)2)?
The molar mass of Ba(OH)2 is 171.34 g/mol. What is the molecular mass of formic acid (HCOOH)?
The molecular mass of formic acid is 46.03 g/mol. What is the molar mass of 1 mol of carbon?
The molar mass of 1 mol of carbon is 12.01 g. You need 2.5 mol of iron (Fe) for an experiment. How many grams of iron must you measure out?
Mass = 2.5 × 55.85 g = 139.63 g. What is the mass of oxygen in 250 g of sulfuric acid (H2SO4)?
Oxygen mass = (64.00/98.08) × 250 g = 163.1 g. What is the mass of a 2.16-mol sample of HNO3?
Mass = 2.16 × 63.01 g = 136.10 g. What is the molar mass of the metal hydroxide?
The molar mass depends on the metal; for NaOH, it is 39.99 g/mol. What is the formula mass of sodium chloride (NaCl)?
The formula mass of NaCl is 58.44 amu. What is the molar mass of calcium carbonate (CaCO3)?
The molar mass of CaCO3 is 100.09 g/mol. What is the molar mass of Mg3(PO4)2?
The molar mass of Mg3(PO4)2 is 262.86 g/mol. What is the total molar mass of hydrogen?
The molar mass of hydrogen is 1.008 g/mol; for H2, it is 2.016 g/mol. What is the molar mass for acetone (C3H6O)?
The molar mass of acetone is 58.08 g/mol. Nitrogen gas is a diatomic molecule. What is the mass of one mole of nitrogen gas?
The mass of one mole of nitrogen gas (N2) is 28.02 g. How many atoms are in one molecule of Na2SO4?
Na2SO4 contains 2 Na, 1 S, 4 O = 7 atoms. How many oxygen atoms are present in Mg(OH)2?
Mg(OH)2 contains 2 oxygen atoms. What is the mass in grams of 0.250 mol of the common antacid calcium carbonate (CaCO3)?
Mass = 0.250 × 100.09 g = 25.02 g. What is the molar mass of ammonium sulfate ((NH4)2SO4)?
The molar mass of ammonium sulfate is 132.14 g/mol. Which of the following correctly describes the formula weight of a compound?
Formula weight is the sum of the atomic masses of all atoms in a compound's formula. What is the molar mass of sodium hydroxide (NaOH)?
The molar mass of NaOH is 39.99 g/mol. What is the theoretical percent mass of magnesium in magnesium oxide (MgO)?
Percent Mg = (24.31/40.31) × 100% ≈ 60.3%. What is the molar mass of N2?
The molar mass of N2 is 28.02 g/mol. What is the molar mass for sulfur dioxide (SO2)?
The molar mass of SO2 is 64.07 g/mol. How many oxygen atoms are in one unit of the compound Ba(OH)2?
Ba(OH)2 contains 2 oxygen atoms. What is the formula mass for potassium nitrate (KNO3)?
The formula mass of KNO3 is 101.10 amu. The compound Fe2O3 contains how many atoms?
Fe2O3 contains 2 Fe and 3 O = 5 atoms per formula unit. What is the molar mass of H2?
The molar mass of H2 is 2.016 g/mol. What is the mass of 1.70 mol of carbon?
Mass = 1.70 × 12.01 g = 20.42 g. What is the molar mass of NH3?
The molar mass of NH3 is 17.03 g/mol. What is the molar mass of copper (Cu)?
The molar mass of copper is 63.55 g/mol. What is the mass of 0.560 moles of chlorine gas (Cl2)?
Mass = 0.560 × 70.90 g = 39.70 g. What is the total mass of 3.01 × 10^23 atoms of helium gas?
Moles = 3.01 × 10^23 / 6.022 × 10^23 = 0.500 mol; mass = 0.500 × 4.00 g = 2.00 g.