Question

the water absorbs about 2120 j and the calorimeter absorbs about 22 j. what is the heat change for the unknown material?
q_unknown = ? j
enter either a + or - sign and the magnitude.

Explanation:

Step1: Understand heat transfer principle

In a calorimetry setup, the heat lost by the unknown material is equal to the heat gained by the water and the calorimeter (assuming no heat loss to the surroundings). So, \( q_{\text{unknown}} = - (q_{\text{water}} + q_{\text{calorimeter}}) \).

Step2: Calculate total heat gained

First, find the total heat absorbed by water and calorimeter: \( q_{\text{water}} + q_{\text{calorimeter}} = 2120\,\text{J} + 22\,\text{J} = 2142\,\text{J} \).

Step3: Determine heat change for unknown

Since the unknown material loses heat (so its heat change is negative), \( q_{\text{unknown}} = - 2142\,\text{J} \).

Answer:

\(-2142\)