Question 28 Answer and Explanation _ACT April 2010 Form 68G Science Section

Passage V

Ethylene oxide, a widely used industrial chemical, has the structure shown below:

Figures 1-3 each show how a property of solutions of ethylene oxide in H₂O varies as the concentration of ethylene oxide increases at 1 atmosphere (atm) of pressure. Concentration is given as the percent ethylene oxide by mass in H₂O (% EO). Figure 1 shows how density at 10°C varies with % EO. Figure 2 shows how freezing point varies with % EO. The bubble point is the lowest temperature at which bubbles of gas (in this case, ethylene oxide) form in a solution. Figure 3 shows how bubble point varies with% EO.

Figures adapted from Old World Industries, The Dow Chemical Company, Shell Chemical Company, Sunoco, Inc., and Equistar Chemicals, LP, Ethyleneoxide (2nd ed.). 1999.

28. According to Figures 2 and 3, at 1 atm, a solution of ethylene oxide in H₂O that has a bubble point of 15°C will have a freezing point closest to which of the following?

F. 0°C

G. 3°C

H. 7°C

J. 10°C

Answer and Explanation

Your Answer is

Correct Answer is H

Explanation

Look at figure 3 first, when the ordinate is 15°C, the abscissa is about 70%;

Look at figure 2 again, when the abscissa is 70%, the ordinate is about 7