When `0.1025 g` of benzoic acid was burnt in a bomb calorimeter the temperature of the calorimeter increased by `2.165^(@)C`. For benzoic acid `DeltaH_("comb")^(@)= -3227 kJ mol^(-1)`. Calculate the heat capacity of the calorimeter.

When `0.1025 g` of benzoic acid was burnt in a bomb calorimeter the te

1.	When `0.1025 g` of benzoic acid was burnt in a bomb calorimeter the temperature of the calorimeter increased by `2.165^(@)C`. For benzoic acid `DeltaH_("comb")^(@)= -3227 kJ mol^(-1)`. Calculate the heat capacity of the calorimeter.
Answer» The equation for the combustion is , `C_(7)H_(6)O_(2)(s) + 7.5 O_(2)(g) rarr 7CO_(2)(g) + 3H_(2)O(l), " " Delta H^(@) = 3227 kJ` Since `7.5` moles of `O_(2)` gas is needed, and 7 moles of `CO_(2)` is produced, some pressure-volume work is done, to the calorimeter: `PV = Delta n_(g) R T`, where `Delta n =(7-7.5) = -0.5 mol` `Delta E = Delta H - Delta Hn_(g) RT` `= -3227 - (0.5 xx 8.314298 xx 298)` `= -3226kJ//mol` (a small correction) The amount of heat produced by 0.1025 g benzoic acid is `q = 0.1025//122.13 xx 3226 = 2.680 kJ` Thus, the heat capacity is `C = q_(v)//Delta T = 2.680//2.165 = 1.238 kJ//K`. After the heat capacity is determined, the calorimeter is ready to be used to measure the enthalpy of combustion of other substances.

Discussion

No Comment Found

Related InterviewSolutions

An intimate mixture of ferric oxide and aluminium is used as solid fuel in rockets. Calculate the fuel value per `cm^(3)` of the mixture. Heats of formation and densities are as follows: `H_(f(Al_(2)O_(3)))=-399kcal" "mol^(-1),H_(f(Fe_(2)O_(3)))=-199kcal" "mol^(-1)` ltbr. Density of `Fe_(2)O_(3)=5.2g//cm^(3)," Density of "Al=2.7g//cm^(3)`
An intimate mixture of `Fe_(2)O_(3)` and `Al` is used in solid fuel rocket. `DeltaH` of `Al_(2)O_(3)` and `Fe_(2)O_(3)` are `399kcal` and `199kcal` respectively. Calculate the fuel value in `kcal g^(-1)` of mixture.
The species which by definition has ZERO standard molar enthyalpy of formation at 298 K isA. `Br_(2)(g)`B. `Cl_(2)(g)`C. `H_(2)O(g)`D. `CH_(4) (g)`
In a constant volume calorimeter, 3.5 g of a gas with molecular weight 28 was burnt in excess oxygen at 298.0 K. The temperature process. Given that the heat capacity of the calorimeter is was found to increase from 298.0 K to 298.45 K due to the combustion process. Given that the heat capacity of the calorimeter is `2.5 kJ K^(-1)`, the numerical value for the enthalpy of combustion of the gas in kJ `"mol"^(-1)` is
Compute the heat of formation of liquie methyl alcohol is kilojoule per mol using the following data. Heat of vaporisation of liquid methyl alcohol `=38kJ//mol`. Heat of formation of gaseous atoms from the elements in their standard states `:H=218kJ // mol, C=715kJ //mol, O=249kJ //mol.` Average bond energies`:` `C-H415kJ//mol, C-O 356kJ//mol, O-H 463kJ //mol.`
The standard heat of formation values of `SF_(6)(g), S(g)`, and `F(g)` are `-1100, 275`, and `80 kJ mol^(-1)`, respectively. Then the average `S-F` bond enegry in `SF_(6)`
Select the correct option.A. `Delta H_(f) [H (g)]` is equal to `Delta H_("atomisaation")` of `H_(2) (g)`B. `Delta H_(BE) (H - H)` is equal to `Delta H_(f)` ofC. `DeltaH_(BE) (H - H)` is equal to `DeltaH_("atomisation")` of `H_(2) (g)`D. `Delta H_("comustion") [H_(2) (g)]` is equal to `Delta H_(f) [H_(2) (g)]`
How much heat will be required at constant pressurent to form `1.28 kg` of `CaC_(2)` from `CaO(s)` & `C(s)`? `{:("Given :",Delta_(f)H^(@) (CaO","s),=,-152 kcal//mol),(,Delta_(f)H^(@) (CaC_(2)","s),=,-14 kcal//mol),(,Delta_(f)H^(@) (CO","g),=,-26 kcal//mol):}`A. `+112` kcalB. `224` kcalC. `3840` kcalD. `2240` kcal
At 300 K, the standard enthalpies of formation of `C_(6)H_(5)COOH (s), CO_(2)(g)` & `H_(2)O (l)` are , `-408, -393` & `-286" kJ mol"^(-1)` respectively. Calculate the heat of combustion of benzoic acid at : (i) constant pressure (ii) constant volume.
Which of the following statement is wrong for `C_((graph ite))rarr C_((diamon d))?DeltaH^(@)=+1.90kJ`A. `DeltaH^(@)``_(f)` for`C_((graph ite))` is zeroB. `DeltaH^(@)``_(f)` for`C_((diamon d))` is `+1.90kJ`C. The enthalpy of formation of element in a form other than its most stable one is non zeroD. None of these

When `0.1025 g` of benzoic acid was burnt in a bomb calorimeter the temperature of the calorimeter increased by `2.165^(@)C`. For benzoic acid `DeltaH_("comb")^(@)= -3227 kJ mol^(-1)`. Calculate the heat capacity of the calorimeter.

Discussion

No Comment Found

Related InterviewSolutions

Reply to Comment