1. Calculate the heat of the reaction for the following reaction:
2C2H2(g) +5O2(g)→4CO2(g+2H2O(g)
∆H = ? kJ/mol
Solve by writing formation equations for each reactant and product and using the ∆H values for each. Is the reaction exothermic or endothermic?
2. Calculate the ∆H value heat for the following reaction:
Ca(OH)2(s) → CaO(s) + H2O(g)
∆H = ? kJ/mol
______________.
Solve by writing formation equations for each reactant and product and using the ∆H values for each.
3. Find the enthalpy of the reaction of magnesium oxide with hydrogen chloride.
MgO(s) + 2HCl(g) → MgCl2(s) + H2O(l)
∆H = ? kJ/mol
______________.
Use the following equations and data.
Mg(s) + 2HCl(g) → MgCl2(s) + H2(g)
∆H = ∆456.9 kJ/mol
Mg(s) + ½ O2(g) → MgO(s)
∆H = ∆601.6 kJ/mol
H2O(l) → H2(g) + ½ O2(g)
∆H = +285.8 kJ/mol
2C2H2(g) +5O2(g)→4CO2(g+2H2O(g)
∆H = ? kJ/mol
Solve by writing formation equations for each reactant and product and using the ∆H values for each. Is the reaction exothermic or endothermic?
2. Calculate the ∆H value heat for the following reaction:
Ca(OH)2(s) → CaO(s) + H2O(g)
∆H = ? kJ/mol
______________.
Solve by writing formation equations for each reactant and product and using the ∆H values for each.
3. Find the enthalpy of the reaction of magnesium oxide with hydrogen chloride.
MgO(s) + 2HCl(g) → MgCl2(s) + H2O(l)
∆H = ? kJ/mol
______________.
Use the following equations and data.
Mg(s) + 2HCl(g) → MgCl2(s) + H2(g)
∆H = ∆456.9 kJ/mol
Mg(s) + ½ O2(g) → MgO(s)
∆H = ∆601.6 kJ/mol
H2O(l) → H2(g) + ½ O2(g)
∆H = +285.8 kJ/mol
Answers & Comments
Verified answer
Answer:
1. To calculate the ∆H for the reaction 2C2H2(g) +5O2(g)→4CO2(g)+2H2O(g), we can use the following formation equations and their corresponding ∆H values:
C2H2(g) + 5/2 O2(g) → 2CO2(g) + H2O(g) (∆H = -1299.5 kJ/mol)
H2(g) + 1/2 O2(g) → H2O(g) (∆H = -285.8 kJ/mol)
To obtain the formation equation for the reactants, we can flip and multiply the above equations as follows:
2CO2(g) + H2O(g) → C2H2(g) + 5/2 O2(g) (∆H = +1299.5 kJ/mol)
H2O(g) → 2H2(g) + O2(g) (∆H = +571.6 kJ/mol)
Now we can add the formation equations for the products and subtract the formation equations for the reactants to get the overall ∆H for the reaction:
4CO2(g) + 2H2O(g) - 2C2H2(g) - 5O2(g) = ∆H
4(-393.5 kJ/mol) + 2(-241.8 kJ/mol) - 2(226.7 kJ/mol) - 5(0 kJ/mol) = ∆H
-3937.4 kJ/mol + (-483.6 kJ/mol) - (-453.4 kJ/mol) = ∆H
∆H = -3901.6 kJ/mol
Since the ∆H value is negative, the reaction is exothermic.
2. To calculate the ∆H value for the reaction Ca(OH)2(s) → CaO(s) + H2O(g), we can use the following formation equations and their corresponding ∆H values:
Ca(OH)2(s) → CaO(s) + H2O(g) (∆H = +65.2 kJ/mol)
H2O(g) → H2(g) + 1/2 O2(g) (∆H = +285.8 kJ/mol)
CaO(s) → Ca(s) + 1/2 O2(g) (∆H = +603.6 kJ/mol)
Now we can add the formation equations for the products and subtract the formation equations for the reactants to get the overall ∆H for the reaction:
CaO(s) + H2(g) + 1/2 O2(g) - Ca(OH)2(s) - H2O(g) = ∆H
(+603.6 kJ/mol) + (0 kJ/mol) + (1/2)(0 kJ/mol) - (+65.2 kJ/mol) - (+285.8 kJ/mol) = ∆H
+253.2 kJ/mol = ∆H
Therefore, the ∆H value for the reaction Ca(OH)2(s) → CaO(s) + H2O(g) is +253.2 kJ/mol.
3. To find the ∆H for the reaction of MgO(s) with HCl(g), we can use the following formation equations and their corresponding ∆H values:
MgO(s) → Mg(s) + 1/2 O2(g) (∆H = -601.6 kJ/mol)
H2(g) + 1/2 O2(g) → H2O(g