Question

question 9.
student 4: added powdered sugar in ice - cold water and stirred.
who likely achieved the fastest dissolution?
a. student 1 because granulated sugar dissolves slowly in cold water.
b. student 2 because powdered sugar has a larger surface area.
c. student 3 because hot water and stirring both increase dissolution rates.
d. student 4 because stirring with powdered sugar helps it dissolve.

Explanation:

To determine who achieved the fastest dissolution, we analyze the factors affecting dissolution rate: surface area and agitation. Powdered sugar has a larger surface area than granulated sugar, and stirring (agitation) increases the dissolution rate. Student 4 used powdered sugar (larger surface area) and stirred, which maximizes the rate. Let's evaluate each option:

• Option A: Granulated sugar dissolves slower, so Student 1 (granulated) would not have the fastest rate. Eliminate A.
• Option B: While powdered sugar has a larger surface area, Student 2 is not stirring. Stirring also increases rate, so B is incomplete. Eliminate B.
• Option C: Hot water increases rate, but the problem states ice - cold water. So Student 3's use of hot water is incorrect as per the problem's conditions (ice - cold water). Eliminate C.
• Option D: Student 4 used powdered sugar (large surface area) and stirred (agitation), both factors that increase dissolution rate. This is the correct combination.

Answer:

D. Student 4 because stirring with powdered sugar helps it dissolve.