A solution of ethylene glycol and water can be used as the coolant in an engine-cooling system. The ethylene glycol concentration in a coolant solution is often given as percent by volume. For example, 100. mL of a coolant solution that is 40.% ethylene glycol by volume contains 40. mL of ethylene glycol diluted with enough water to produce a total volume of 100. mL. The graph below shows the freezing point of coolants that have different ethylene glycol concentrations.
69 Explain, in terms of particle distribution, why a coolant solution is a homogeneous mixture. [1]
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| All particles are uniformly dispersed. |
70 Explain, in terms of the molecular polarity, why ethylene glycol dissolves in water to form a solution. [1]
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| Water molecules and ethylene glycol molecules are both polar |
71 Identify the percent by volume of ethylene glycol in a solution that freezes at -10.°C. [1]
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| any answer from 21 to 23% |
72 One engine-cooling system has a volume of 6400 mL. Determine the volume of ethylene glycol in the completely filled engine-cooling system when the concentration of ethylene glycol is 50.% by volume. [1]
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