Q.1
Sometimes athletes take drugs to enhance their performance. One such drug is ephedrine which has the formula C H NO. What is the molecular mass of ephedrine?
  • 55 amu
  • 165 amu
  • 40 amu
  • 164 amu
Q.2
Amphetamine, another drug, has the formula C H N. The molecular mass is 135 amu. Calculate the percentage by mass of hydrogen in amphetamine.
  • 9.6%
  • 80%
  • 10.4%
  • 0.7%
Q.3
A substance used as a cosmetic by the Ancient Egyptians has been analysed. It was found to contain 76% lead, 13% chlorine, 2.2% carbon and 8.8% oxygen. Calculate the empirical formula of this compound.
  • PbCl6 CO4
  • Pb4Cl4C2O6
  • PbClCO3
  • Pb2Cl2CO3
Q.4
Some toothpastes contain sodium fluoride. This compound has the formula NaF. Calculate the relative formula mass of this compound.
  • 42 amu
  • 42
  • 30 amu
  • 20 amu
Q.5
Calculate the % by mass of fluorine in sodium fluoride.
  • 55%
  • 45%
  • 48%
  • 0.45%
Q.6
A tube of toothpaste contains 1.5 g of sodium fluoride. Calculate the mass of sodium in this tube of toothpaste.
  • 0.675 g
  • 0.825
  • 0.72 g
  • 0.825 g
Q.7
Calcium hypochlorite tablets are added to swimming pools to kill microorganisms. The formula of calcium hypochlorite is CaCl O . Calculate the relative formula mass of calcium hypochlorite.
  • 143 amu
  • 91.5 amu
  • 45 amu
  • 70 amu
Q.8
Calculate the percentage by mass of oxygen in calcium hyopchlorite.
  • 22%
  • 88%
  • 11%
  • 78%
Q.9
Calculate the mass of oxygen in a 50g tablet of calcium hypochlorite.
  • 39%
  • 5.5 g
  • 11 g
  • 44 g
Q.10
Car airbags inflate when an impact causes a mixture of chemicals to react. The mixture of chemicals contains sodium azide (NaN ) which undergoes thermal decomposition to produce sodium and nitrogen. Calculate the mass of sodium that would be produced when 170 g of sodium azide decomposes.
  • 109.8 g
  • 60.2 g
  • 105.6 g
  • 58.4 g
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