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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  o C 
 31.593 o C 
 27.357 o C 
 
 
 Initial Temperature 
 20.675 o C 
 20.622 o C 
 20.504 o C 
 
 
 Change in Temperature 
 4.397 o C 
 10.972 o C 
 6.853 o C 
 
 
 
 Calculations: 
 Mass R1 = 100mL*1.00g/mol=100g +2.00g = 102 g 
 Mass R2 = 100mL*1.00g/mol=100g +2.00g = 102g 
 Mass R3 = 50mL*1.00g/mol=50g *2= 100g 
 
 q R1 = 4.18*102*4.397 =1875J /1000= 1.875kJ 
 q R2 = 4.18*102*10.972 =4678J /1000= 4.678kJ 
 q R3 =4.18*100*6.853 =2865J /1000= 2.865kJ 
 ΔH=-q       q=-ΔH