Passage V

When rocks are melted at very high temperatures beneath Earth's surface, magma (molten rock) is formed. The gases CO2, and H2O can dissolve in magma. Figure 1 shows, for 4 different magmas (leucitite, basanite, rhyolite, and tholeiitic basalt), how the solubility of CO2 in the magma at 1,150°C varies with pressure (in megapascals MPa).

Figure 2 shows, at 3 different pressures, how the solubility of CO2 in rhyolite magma varies with temperature.

Figure 3 shows, at 4 different pressures, how the solubility of CO2, in rhyolite magma at 750°C varies with the weight percent of H2O in the magma.

32. According to Figure 2, increasing the temperature from 650°C to 1,150°C has the lesser effect on the solubility of CO2 in rhyolite magma at which pressure, 100 MPa or 300 MPa?

Answer and Explanation

Your Answer is

Correct Answer is F

Explanation

Looking at Figure 2, the line at 100 MPa is more gentle, indicating that the increase in temperature on the abscissa has relatively little effect on the solubility of CO2. Under the pressure of 100 MPa, the ordinate is about 800 at 650°C, and about 400 at 1150°C, and the difference is 400, so option F is in line.