1. Heating Curves and Calculations
Quiz tomorrow

2. Observe the heating curve below: What phase is substance B at 60oC?
Temp (oC)
250
220
160 90 65 45
Substance A
Substance B
Substance C
Solid (it’s below the melting point)

3. Observe the heating curve below: What is the melting point of substance A?
Temp (oC)
250
220
160 90 65 45
Substance A
Substance B
Substance C
45oC

4. Observe the heating curve below: What is the boiling point of substance C?
Temp (oC)
250
220
160 90 65 45
Substance A
Substance B
Substance C
160oC

5. Substance B (longest vaporization region)
Observe the heating curve below: Which substance has the greatest DHVAP?
Temp (oC)
250
220
160 90 65 45
Substance A
Substance B
Substance C
Substance B (longest vaporization region)

6. Observe the heating curve below: Which substance has the lowest DHFUS?
Temp (oC)
250
220
160 90 65 45
Substance A
Substance B
Substance C
Substance C (shortest melting region)

7. A (gentle slope, heats up slowly)
Observe the heating curve below: Which substance has the highest specific heat as a solid?
Temp (oC)
250
220
160 90 65 45
Substance A
Substance B
Substance C
A (gentle slope, heats up slowly)

8. C (drastic slope, heats up quickly)
Observe the heating curve below: Which substance has the lowest specific heat as a vapor?
Temp (oC)
250
220
160 90 65 45
Substance A
Substance B
Substance C
C (drastic slope, heats up quickly)

9. None (it stays liquid the whole time)
Observe the heating curve below: If substance A is heated from 52oC to 235oC, how many phase changes will it undergo?
Temp (oC)
250
220
160 90 65 45
Substance A
Substance B
Substance C
None (it stays liquid the whole time)

10. Any temperature between 160 and 220
Observe the heating curve below: Guess a temperature where B is liquid but C is vapor
Temp (oC)
250
220
160 90 65 45
Substance A
Substance B
Substance C
Any temperature between 160 and 220

11. Observe the heating curve below: Which will release more heat
Observe the heating curve below: Which will release more heat? Condensing of 1 mole of A Freezing 1 mole of B
Temp (oC)
250
220
160 90 65 45
Substance A
Substance B
Substance C
Freezing 1 mole of B

12. Use these charts to answer the questions on the following slides.

13. How much heat is released when 2.00 moles of water freeze?
-12.0 kJ of heat

14. How much heat is absorbed when 5.00 moles of ammonia vaporize?
117 kJ of heat

15. How much heat is absorbed when 15.0 grams of ethanol (C2H5OH) melts?
1.61 kJ of heat

16. How much heat is absorbed by 72
How much heat is absorbed by grams of water that rises in temperature from 50.0oC up to 110.0oC
Something around 179 kJ or 179,000 J
Heating up liquid: J
Vaporization: kJ
Heating up vapor: J