Question

Linda performed the following trials in an experiment. Trial 1: Heat 30.0 grams of water at 0 °C to a final temperature of 40.0 °C. Trial 2: Heat 40.0 grams of water at 30.0 °C to a final temperature of 40.0 °C. Which statement is true about the experiments?
(a) The heat absorbed in Trial 1 is about 1,674 J greater than the heat absorbed in Trial 2.
(b)The heat absorbed in Trial 1 is about 3,347 J greater than the heat absorbed in Trial 2.
(c)The same amount of heat is absorbed in both the experiments because the heat absorbed depends only on the final temperature.
(c) The same amount of heat is absorbed in both the experiments because the product of mass, specific heat capacity, and change in temperature are the same.

Answer 1

Answer: The correct answer is Option b.

Explanation:

To calculate the amount of heat absorbed or released, we use the following equation:

$q=mc\Delta T$    .....(1)

where, q = amount of heat absorbed or released.

m = mass of the substance

c = heat capacity of  water = 4.186 J/g ° C      

$\Delta T$ = Change in temperature

• For Trial 1:

We are given:

$m=30g\\\Delta T=[40-0]^oC=40^oC\\q=?J$

Putting values in equation 1, we get:

$q=30g\times 4.186J/g^oC\times 40^oC$

q = 5023.2 J

• For trial 2:

We are given:

$m=40g\\\Delta T=[40-30]^oC=10^oC\\q=?J$

Putting values in equation 1, we get:

$q=40g\times 4.186J/g^oC\times 10^oC$

q = 1674.4 J

Heat gained by Trial 1 than trial 2 = $(5023.2-1674.4)J=3347J$

Hence, the amount of heat gained in Trial 1 about 3347 J more than the heat released in Trial 2.

Thus, the correct answer is Option b.