Let's go through your questions step by step.
Temperature Change Calculation:
You correctly calculated the temperature change (ΔT) as follows:
ΔT = Tf - Ti
ΔT = 21°C - 4°C = 17°C
Energy Change:
It appears you have identified an energy change (ΔE), but you should ensure that this is consistent with the temperature change being calculated.
Filling in the Blanks:
- Blank 1 (Starting Temperature): 4°C (this should reflect the initial temperature)
- Blank 2 (Change in Temperature): 17°C (this is the change you calculated)
- Blank 3 (Ending Temperature): 21°C (the final temperature after the change)
- Blank 4: 4 kJ/mol (this is the energy change, assuming it's the energy change associated with the reaction)
Question 2 - Endothermic or Exothermic?
- The reaction is endothermic (a). An endothermic reaction absorbs heat, which is consistent with a temperature decrease in the surroundings (like in a cold pack).
Question 3 - Hot or Cold Pack?
- This reaction makes a cold pack (b). Since it's endothermic, it absorbs heat from its surroundings, making it feel cold.
Summary:
- Blank 1: 4°C
- Blank 2: 17°C
- Blank 3: 21°C
- Blank 4: 4 kJ/mol
- Question 2 Answer: a (Endothermic)
- Question 3 Answer: b (Cold pack)