Question

Morgan did an experiment to see the effect of water temperature on the rate at which sugar dissolves. She placed a sugar cube in several glasses and added the same amount of water at 3 different temperatures to the glasses. She then observed how long it took the sugar to dissolve in each temperature. How should Morgan organize her data?
A. by size of the glass
B. by the water temperature
C. by the amount of sugar placed in each glass
D. by the amount of sugar left in the glass after the experiment

Answer 1

Answer: B. By the water temperature

Explanation: Increase in temperature increases the rate of a chemical reaction. The temperature of water in the glass determines how fast or slow the sugar cube dissolves in the water (i.e., the time taken for the sugar cube to dissolve in water).

Answer 2

Answer:

B is correct → since temperature can be measured confidently and the variations with temperature are greater ( then the errors in measuring time diminishes)

Explanation:

A is not correct → since the sugar cubes will be still surrounded by water at the temperature chosen regardless of the size of the glass, organising the data by size of the glass is not correct since the glass size does not affect in a significant way to the results ( it could affect the cooling rate of water due to the exposed surface , it but would be insignificant)  

C is not correct → since the sugar cubes are approximately of the same size , putting 2 cubes or "n" cubes will not affect the time significantly since each cube is still surrounded by water at the same temperature and behaves independently from others , then each cube dissolves at the same time ( there would be small variations due to the different sizes of the cubes and the small variation due to the limited mass of water)

D is not correct → since the solubility of sugar in water is high , the amount left after the experiment would be very small ( thus the relative errors are high) and the sugar would be contaminated with water in the weighting operation, leading to more errors

B is correct → since temperature can be measured confidently and the variations with temperature are greater ( then the errors in measuring time diminishes)