IMAT Chemistry questions

Sample Chemistry practice questions

1. 1Chemical bond · IMAT Doutor

   Water boils at 100 degrees Celsius while hydrogen sulfide, a heavier molecule, boils at about minus 60. The best explanation is that:
   1. AWater molecules are held by covalent bonds to each other, which must be broken for the liquid to boil
   2. BWater has a higher molar mass, so more energy is needed to move its molecules apart into the gas phase
   3. CWater molecules are ionic, so they attract each other much more strongly than those of hydrogen sulfide
   4. DHydrogen sulfide is a solid at room temperature, so its boiling point cannot be compared with that of water
   5. EWater molecules are held together by hydrogen bonds, which sulfur is not electronegative enough to form
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2. 2Aromatic hydrocarbons · IMAT Doutor

   All six carbon-carbon bonds in benzene have the same length, intermediate between a single and a double bond. This shows that:
   1. ABenzene is a mixture of two different compounds that constantly convert into each other faster than they can be separated
   2. BThe bonds are ionic, with charge shared equally around the ring
   3. CThe molecule is not three alternating single and double bonds, but a single delocalised system
   4. DBenzene contains six double bonds, one between each pair of carbons
   5. EThe carbon atoms are of two different kinds, alternating around the ring
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3. 3Compounds and elements · IMAT Doutor

   A colourless liquid is heated and separates into two liquids that boil at different temperatures, each of which is then found to be pure. The original liquid was:
   1. AImpossible to classify from this evidence, since both liquids are colourless like the original
   2. BA mixture, because distillation separates by boiling point without breaking bonds
   3. CA compound, because it broke into two substances when heated to its boiling point
   4. DAn element, since each of the two liquids obtained was found to be pure
   5. EAn allotrope, since both liquids came from the same original substance
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4. 4Structural formulas · IMAT Doutor

   A compound has the empirical formula CH2O and a molar mass of 180 g/mol. Its molecular formula is: (C = 12, H = 1, O = 16)
   1. AC6H12O6
   2. BC3H6O3
   3. CCH2O
   4. DC2H4O2
   5. EC9H18O9
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5. 5The concept of acid and base · IMAT Doutor

   25 mL of 0.1 M sodium hydroxide is exactly neutralised by 25 mL of sulfuric acid. The concentration of the acid is:
   1. A0.2 M
   2. B0.025 M
   3. C0.5 M
   4. D0.05 M
   5. E0.1 M
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