General Chemistry (Part 3): Thermochemistry
1) What is thermochemistry exactly?
2) Why do we learn thermochemistry?
3) Give 2 examples of thermochemistry applications in daily life.
4) State a thermochemical equation if ammonium chromate (solid) formation releases 1806.7 kJ/mole of energy.
5) 130 grams acetylene (C2H2) can raise 20 liters of water from 200C to 1000C. Calculate enthalpy change of water and state its thermochemical equation if known density of water = 1 gr/ml and heat capacity of water = 1 J/gr.0C.
6) Known the enthalpy change of ethylene and ethane formations in the manner are 51,8 kJ and 64,4 kJ, what heat will be released by ethylene produces ethane?
7) By using bond energy data in your text book, calculate how much heat will be included to react ethylene and chlorine form ethyl chloride and chloric acid? Please write the bond energy of each substance.
8) Known the following thermochemical equations:
XO2 + CO -® XO + CO2 DH = - 20 kJ
X3O4 + CO -® 3 XO + CO2 DH = + 6 kJ
3 X2O3 + CO -® 2 X3O4 + CO2 DH = - 12 kJ
Calculate the enthalpy change for the following equation:
2 XO2 + CO -® X2O3 + CO2
9) Explain latent heat and sensible heat.
10) What is 1 Btu (British Thermal Unit)? Calculate the number of joules in 1 Btu of heat.
11) What does Hess' Law state and give one example to explain your answer (you may use an example from daily life or even everywhere).
12) The natural gas in methane reacts with oxygen to give carbon dioxide and water. Calculate the heat given off when 0.010 mole of methane reacts with excess oxygen in a bomb calorimeter if the temperature of 1.00 kilogram of water in the bath surrounding the bomb increases by 1.918 0C.
13) How do we measure the enthalpy of a reaction? Explain your answer sharply.
14) What are differences between an exothermic reaction and an endothermic reaction?
15) If a reaction can not go spontaneously what you will do? Explain your answer by giving an example of each way.
16) Predict which of the following substances should have an enthalpy of formation equal to zero:
(a) Hg (l)
(b) Br2 (g)
(c) H (g)
Give your reason.
17) What value of heat will be included in the following blank enthalpy change?
18) How much heat is given off when 1 mole of nitrogen reacts with 2 moles of oxygen to give 2 moles of nitrogen oxide gas, if for the given balanced reaction is 33.2 kJ/mole of nitrogen oxide?
19) Explain why there is only one value for the standard enthalpy of reaction for a chemical reaction whereas there can be many different values for the enthalpy of reaction.
20) Use the standard enthalpies of formation in your text book to determine whether heat is given off or absorbed when limestone (calcium carbonate) is converted to lime (calcium oxide) and carbon dioxide. Write the heat value included.
21) Use bond dissociation enthalpies to estimate the enthalpy of reaction for the combustion of carbon sulfide in the phase gas to produce carbon dioxide and sulfur dioxide.
22) Calculate the standard enthalpy change for magnesium in the solid phase reacts with fluorine in the gas phase to create magnesium fluoride in the solid phase, assuming that 1.00 gram of magnesium gives off 46.22 kJ of heat when it reacts with excess fluorine.