# Page 35
8\. Rinse and dry the temperature probe, cup, and stirring rod. Dispose of the solution as directed.
9\. Repeat steps 4-8, using 100.0mL of 0.5M hydrochloric acid instead of water. Use the same amount of NaOH.
10\. Repeat steps 4-8, instead using 50.0mL of 1.0M HCl, and using 50.0mL of 1.0M NaOH.
Observations:
Combining the water and NaOH creates some bubbles. Combining 1.0M HCl and NaOH turns a litle pink.
Data:
|
| Reaction 1
| Reaction 2
| Reaction 3
|
| Mass NaOH
| 2.00g
| 2.00g
| |
| Mass Total
| 102g | 102g | 100g |
| Final Temperature
| 25.073 oC
| 31.593 oC
| 27.357 oC
|
| Initial Temperature
| 20.675 oC
| 20.622 oC
| 20.504 oC
|
| Change in Temperature
| 4.397 oC
| 10.972 oC
| 6.853 oC
|
Calculations:
MassR1= 100mL\*1.00g/mol=100g +2.00g = 102g
MassR2= 100mL\*1.00g/mol=100g +2.00g = 102g
MassR3= 50mL\*1.00g/mol=50g \*2=100g
qR1= 4.18\*102\*4.397 =1875J /1000=1.875kJ
qR2= 4.18\*102\*10.972 =4678J /1000=4.678kJ
qR3=4.18\*100\*6.853 =2865J /1000=2.865kJ
ΔH=-q q=-ΔH