Thermochemical Equations
Chemistry ⇒ Thermochemistry and Energetics
Thermochemical Equations starts at 10 and continues till grade 12.
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Describe how to write a thermochemical equation for the dissolution of NaCl(s) in water, given ΔH = +3.9 kJ/mol.
Describe the difference between an endothermic and an exothermic thermochemical equation.
Describe the steps to write a thermochemical equation for the neutralization of HCl(aq) with NaOH(aq), given ΔH = -57.1 kJ/mol.
Explain why it is important to specify the physical states of substances in a thermochemical equation.
Fill in the blank: The enthalpy change for the combustion of 2 moles of methane is ______ kJ, given ΔH = -890 kJ/mol.
Fill in the blank: The enthalpy change for the reaction: H2(g) + 1/2O2(g) → H2O(l) is called the standard enthalpy of ______ of water.
Given the following thermochemical equations: (1) C(s) + O2(g) → CO2(g); ΔH = -393.5 kJ, (2) H2(g) + 1/2O2(g) → H2O(l); ΔH = -285.8 kJ, calculate the enthalpy change for the reaction: C(s) + 2H2(g) + O2(g) → CH3OH(l), given ΔHf° (CH3OH) = -238.7 kJ.
Given the thermochemical equation: 2Al(s) + 3Cl2(g) → 2AlCl3(s); ΔH = -1408 kJ, what is the enthalpy change for the formation of 1 mole of AlCl3(s)?
If a thermochemical equation is multiplied by 0.5, what happens to the value of ΔH? (1) It is halved, (2) It is doubled, (3) It remains the same, (4) It becomes negative
If a thermochemical equation is reversed, what happens to the sign of ΔH? (1) It remains the same, (2) It changes sign, (3) It doubles, (4) It is halved
If the coefficients in a thermochemical equation are multiplied by 2, what happens to the value of ΔH? (1) It is halved, (2) It is doubled, (3) It remains the same, (4) It becomes zero
If the enthalpy change for a reaction is +50 kJ, what does this indicate about the reaction? (1) It is exothermic, (2) It is endothermic, (3) It is spontaneous, (4) It is at equilibrium
Fill in the blank: The enthalpy change for a reaction is represented by the symbol ______.
Fill in the blank: The enthalpy change for a reaction is usually expressed in units of ______ per mole.
Fill in the blank: The enthalpy change for a reaction, ΔH, is negative for ______ reactions.
Fill in the blank: The enthalpy change for the combustion of 2 moles of methane is ______ kJ, given ΔH = -890 kJ/mol.
State whether the following statement is true or false: In a thermochemical equation, the physical states of reactants and products must be specified.
True or False: The coefficients in a thermochemical equation refer to the number of moles of each substance involved in the reaction.
True or False: The enthalpy change for a reaction can be calculated using Hess's Law and known thermochemical equations.
True or False: The enthalpy change for a reaction can be calculated using standard enthalpies of formation.
