Chemistry questions
29404 published questions with worked solutions.
- If the bond dissociation energies of XY, X_2 and Y_2 (all diatomic molecules) are in the ratio of 1 : 1 : 0.5 and H_f for the...
- The value of H for cooling 2 moles of an ideal monoatomic gas from 225^ to 125^ at constant pressure will be [given C_p = 5 2 R]
- In which of the following reactions, the enthalpy is the least?
- C(s) + O_2(g) CO_2(g) , H = -94 kcal 2CO(g) + O_2 2CO_2(g) , H = -135.2 kcal The heat of formation of CO(g) is
- The heat of formations for CO_2(g) , H_2O(l) and CH_4(g) are -400 kJ mol^ -1 , -280 kJ mol^ -1 and -70 kJ mol^ -1 , respectively....
- A hypothetical reaction A 2B , proceeds through following sequence of steps A C; H = q C D; H = v 12 D B; H = x Then, the heat of...
- H for the reaction, C(Graphite) + 2H_2(g) CH_4(g) at 298 K and 1 atm is -17900 cal. The E for the above conversion would be
- The decreasing order of bond dissociation energies of C - C , C - H and H - H bonds is
- If the bond energies of H - H, Br - Br and H - Br are 433, 192 and 364 kJ mol^ -1 respectively, then E for the reaction, H_2(g) +...
- The internal energy change when a system goes from state A to B is 40 kJ/mol. If the system goes from A to B by a reversible path...
- Given, 2Fe + 32 O_2 Fe_2O_3 , H = -193.4 kJ; Mg + 12 O_2 MgO , H = -140.2 kJ; What is the H for the following reaction? 3Mg +...
- Enthalpy of formation of HF and HCl are -161 kJ and -92 kJ, respectively. Which of the following statements is incorrect?
- For the reaction, 2H_2 + O_2 2H_2O , H = -571. Bond energy of H-H = 435, O=O = 498, then calculate the average bond energy of O-H...
- The bond energy of an O - H bond is 109 kcal/mol. When 1 mole of water is formed, then
- Given the following thermochemical equations, Zn + 12 O_2 ZnO + 84 , 000 cal Hg + 12 O_2 HgO + 21 , 700 cal Accordingly the heat...
- The enthalpy of vaporisation of liquid water using the data H_2(g) + 12 O_2(g) H_2O(l); H = -285.77 kJ/mol H_2(g) + 12 O_2(g)...
- Energy required to dissociate 4 g of gaseous hydrogen into free gaseous atoms is 208 kcal at 25^ . The bond energy of H - H will...
- The enthalpy change ( H) for the process, N_2H_4(g) 2N(g) + 4H(g) is 1724 kJ mol^ -1 . If the bond energy of N - H bond in...
- CH_2 = CH_2(g) + H_2(g) CH_3 - CH_3(g) The heat of reaction is [bond energy of C - C = 80 kcal, C = C = 145 kcal, C - H = 98...
- The following is (are) endothermic reactions I. combustion of methane II. decomposition of water III. dehydrogenation of ethane...