Based on the given data in the table, let's solve each part of the problem step-by-step:
### 1. Heating Scenario
When equal masses of substances A, B, and C are given equal amounts of heat, the temperature change for each substance depends on its specific heat capacity. The formula for temperature change is:
[tex]\[ \Delta T = \frac{Q}{mc} \][/tex]
where \( Q \) is the amount of heat added, \( m \) is the mass, and \( c \) is the specific heat capacity.
From the given specific heat capacities:
- \( c_A = 2100 \, \text{J/kg°C} \)
- \( c_B = 910 \, \text{J/kg°C} \)
- \( c_C = 138 \, \text{J/g°C} \)
- First, convert \( c_C \) to J/kg°C:
[tex]\[ c_C = 138 \times 1000 = 138000 \, \text{J/kg°C} \][/tex]
Since they have been given equal heat:
- Substance A will have a moderate temperature increase.
- Substance B will have a greater temperature increase than A.
- Substance C will have the maximum temperature increase because its specific heat capacity is significantly lower.
Thus, C will reach the maximum temperature upon heating since it has the lowest specific heat capacity.
### 2. Cooling Scenario for Heating and Cooling Purposes
Cooling suitability is determined by the ability of a substance to absorb or retain heat for the same temperature change.
- A is suitable for cooling purposes because it has the highest specific heat capacity (2100 J/kg°C). This means it can absorb more heat energy without a significant increase in temperature, staying cooler longer.
Heating suitability is typically the reverse, but since we need to specify cooling purposes, then A is the answer for cooling.
### 3. Cooling Rate
To determine which substance cools faster when left at \( 80^\circ C \):
- The substance with the lowest specific heat capacity will cool faster since it can transfer heat energy more efficiently.
Given the specific heat capacities:
- \( c_A = 2100 \, \text{J/kg°C} \)
- \( c_B = 910 \, \text{J/kg°C} \)
Since \( c_B \) is lower than \( c_A \), B will cool faster.
### 4. Thermometric Liquid
A thermometric liquid should have a low specific heat capacity so it can respond quickly to temperature changes.
Given the specific heat capacities:
- C is suitable as a thermometric liquid because it has the lowest specific heat capacity (138 J/g°C or 138000 J/kg°C), meaning it will respond most quickly to temperature changes.
In summary:
- C will reach the maximum temperature when heated equally.
- A is suitable for cooling purposes because it has the highest specific heat capacity.
- B will cool faster because it has a lower specific heat capacity than A.
- C is suitable as a thermometric liquid due to its low specific heat capacity.
