Passage III

Ice cream was made by stirring an ice cream mixture (M1) at a constant rate in the apparatus shown in Figure 1.

Figure 2 shows how the temperature of M1 and the temperature of the salt/ice mixture varied with mixing time.

The viscosity (resistance to flow) of M1 was monitored by measuring how the current drawn by the motor turning the stirring paddle changed with mixing time. Two other ice cream mixtures (M2 and M3) were also monitored under conditions identical to those used during the mixing of M1 (see Figure 3).

Figures adapted from D. Gibbon et al. , "The Thermodynamics of Home-Made lce Cream" ©1992 by Division of Chemical Education, lnc., American Chemical Society.

13. A fourth ice cream mixture (M4) was monitored under the same conditions used to gather the data for Figure 3. The current at 0 min was 1.33 amperes. How did the initial viscosity of M4 compare with that of M1-M3 ? The initial viscosity of M4 was:

Answer and Explanation

Your Answer is

Correct Answer is B

Explanation

See figure 3, the greater the current intensity, the greater the viscosity. The initial current of M4 is 1.33 A, which is greater than the initial current of M3 and smaller than the initial current of M1 and M2, so the initial viscosity of M4 should also be larger than that of M3 and smaller than that of M1 and M2