Students were asked to determine the heat of reaction for the neutralization of a newly synthesized monoprotic acid HX and NaOH. They first calibrated the styro ball calorimeter using the reaction of 15.0 mL of 0.100 M HCl and 20.0 mL of 0.0500 M KOH. This recorded a change in temperature from 26.5 °C to 31.8 °C. Afterwards, they determined the heat of reaction for a mixture of 5.00 mL, 1.00 M NaOH and 10.0 mL, 1.00 M HX. This showed an increase in temperature of 3.6 °C. i. What is the heat capacity of the calorimeter in J/℃ (∆? =-55.85 ?????????????? kJ/mol)? ii. Write the balanced chemical and net ionic equations for the reaction of NaOH and HX . iii. What is the experimental enthalpy (in kJ/mol) for the neutralization reaction between HX and NaOH ? iv. Is the reaction between NaOH and HX endothermic or exothermic ?
Thermochemistry
Thermochemistry can be considered as a branch of thermodynamics that deals with the connections between warmth, work, and various types of energy, formed because of different synthetic and actual cycles. Thermochemistry describes the energy changes that occur as a result of reactions or chemical changes in a substance.
Exergonic Reaction
The term exergonic is derived from the Greek word in which ‘ergon’ means work and exergonic means ‘work outside’. Exergonic reactions releases work energy. Exergonic reactions are different from exothermic reactions, the one that releases only heat energy during the course of the reaction. So, exothermic reaction is one type of exergonic reaction. Exergonic reaction releases work energy in different forms like heat, light or sound. For example, a glow stick releases light making that an exergonic reaction and not an exothermic reaction since no heat is released. Even endothermic reactions at very high temperature are exergonic.
Students were asked to determine the heat of reaction for
the neutralization of a newly synthesized monoprotic acid HX and NaOH. They
first calibrated the styro ball calorimeter using the reaction of 15.0 mL of 0.100 M
HCl and 20.0 mL of 0.0500 M KOH. This recorded a change in temperature from
26.5 °C to 31.8 °C. Afterwards, they determined the heat of reaction for a mixture
of 5.00 mL, 1.00 M NaOH and 10.0 mL, 1.00 M HX. This showed an increase in
temperature of 3.6 °C.
i. What is the heat capacity of the calorimeter in J/℃ (∆? =-55.85
??????????????
kJ/mol)?
ii. Write the balanced chemical and net ionic equations for the reaction of NaOH
and HX .
iii. What is the experimental enthalpy (in kJ/mol) for the neutralization reaction
between HX and NaOH ?
iv. Is the reaction between NaOH and HX endothermic or exothermic ?
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