Question

please help me with these annoying multiple choice questions. Thanks

Which of the following statements about the reaction shown on the right, in figure 2, is correct? 8. a.) The activation energy of the reverse reaction is smaller than that On patential of the forward reaction b.) The reaction is endothermic c.) The second step of the reaction mechanism is the rate determining step d.) This mechanism is composed of two steps Figure 2: Potential energy diagram of a hypothetical reaction 10. One of the naturally occurring radioactive series begins with radioactive 238U. It undergoes a series of decays, one of which is: alpha, beta, beta, alpha, alpha, alpha, alpha, alpha, beta, beta, alpha, beta, alpha, beta. What is the final resulting nuclide of this decay series? a.) Lead-204 b.) Platinum-204 c.) Lead-206 d.) Platinum-206 11. Which of the following is an endothermic reaction? ΔΗ--56.5 kJ b.) Fusion of water c.) Combustion of hexane 12. The e temperature remains constant as some process occurs within a substance. How might the substance be changing? a.) The chemical make up of the substance is changing b.) The state (solid, liquid, gas) of the substance is changing c.) The amount of rotational energy is decreasing d.) The amount of vibrational energy is increasing 13. Calorimetry/calorimeters are based on which of the following fundamental principles? a.) Mass is never lost in a chemical reaction b.) E me2 c.) Energy is conserved, it cannot be created or destroyed d.) It really be like that sometimes 14. When a catalyst is added to a reaction, AH will a.) increase slowly b.) remain constant c.) decrease slowly d.) increase rapidly due to the alternate pathway 15. One mole of nitrogen reacts with one mole of oxygen to form two moles of nitric oxide in the reaction: If AHP denotes the standard enthalpy of formation of products, and 솨, denotes the standard enthalpy of formation of reactants, then which of the following is true? d.) Impossible to tell from the given data 16. The specific heat capacity of ethyl alcohol is 2.45 J g C and that of silver is 0.235 J/g C Adding the same amount of energy to the same mass of each substance, it can be concluded that a.) The temperature of the ethyl alcohol increases more than that of the silver b.) The temperature of the silver increases more than that of the ethyl alcohol c.) The potential energy of the ethyl alcohol increased more than that of the silver d.) The temperature of the ethyl alcohol increases by the same amount as the silver The addition of 9.54 kJ of heat is required to raise the temperatures of 225.0g of a liquid hydrocarbon from 20.5℃ to 45.0°C. What is the specific heat capacity of this hydrocarbon? a.) 0.94 J/g C b.) 1.73 J/g oC c.) 1.88 J/g oC d.) 0.002 J/g °C 1·

Answer 1

8] option C is correct

the reaction is endothermic because the potential energy for Reactant is greater than products that is Product is more stable hence reaction is exothermic.

always as per activation energy theory state that rate determined by measuring at which rate activated complex is being converted to product.

10] total number of alpha decays =8

total number of beta decays =6

final elements atomic mass is reduced to = 238 - 4x8 = 206

final elements atomic number increased to = 92+ 6x1-8x2 = 82

option C correct Lead - 206

11] fusion of water needs heat energy to melt hence option B fusion of water is correct

12] option D correct

because vibrational energy is independent to temperature change.

13] option C is correct

because principal of calorimetry is CONSERVATION OF ENERGY

14] option B correct

catalyst don't change enthalpy but it changes activation energy by changing reaction pathways.

15] option A correct

for delta H = delta H Product - delta H reactant

since delta H of reaction is positive value delta H product > H Reactant and reaction is endothermic.