CHEM1305.300
Marlys Baldwin
September 12, 2021
VCL: 3-1 Endothermic vs. Exothermic, and 3-10 Heat of
Reaction: NaOH(aq) + HCl(aq)
Data and Post-lab Questions 3-1
Mixture T1 T2 ΔT (T2-T1) Endo- or
exothermic?
NaCl(s) + H2O(l) 25.01 24.99 0.02 Endo (+)
NaNO3(s) + H2O(l) 25.01 24.02 0.01 Endo (+)
NaCH3COO(s) + 25.00 25.93 0.92 Exo (-)
H2O(l)
1) Calculate ΔT (T2-T1) for each mixture and record it in the data table.
2) An endothermic process absorbs heat and an exothermic process gives off heat.
Identify each process in the table as endothermic or exothermic.
3) What is the ΔT sign for an endothermic reaction?
4) Which solution(s) had little or no change in temperature?
Nacl + H2O
Data and Post-lab Questions 3-10
NaOH/HCl
Initial temperature (oC) 25.01
Final temperature (oC) 31.06
1) Is the observed reaction endothermic or exothermic? What will be the sign of
ΔHrxn? (rxn stands for reaction)
Marlys Baldwin
September 12, 2021
VCL: 3-1 Endothermic vs. Exothermic, and 3-10 Heat of
Reaction: NaOH(aq) + HCl(aq)
Data and Post-lab Questions 3-1
Mixture T1 T2 ΔT (T2-T1) Endo- or
exothermic?
NaCl(s) + H2O(l) 25.01 24.99 0.02 Endo (+)
NaNO3(s) + H2O(l) 25.01 24.02 0.01 Endo (+)
NaCH3COO(s) + 25.00 25.93 0.92 Exo (-)
H2O(l)
1) Calculate ΔT (T2-T1) for each mixture and record it in the data table.
2) An endothermic process absorbs heat and an exothermic process gives off heat.
Identify each process in the table as endothermic or exothermic.
3) What is the ΔT sign for an endothermic reaction?
4) Which solution(s) had little or no change in temperature?
Nacl + H2O
Data and Post-lab Questions 3-10
NaOH/HCl
Initial temperature (oC) 25.01
Final temperature (oC) 31.06
1) Is the observed reaction endothermic or exothermic? What will be the sign of
ΔHrxn? (rxn stands for reaction)
