1st Year Chemistry First half Book Paper

Q1. Multiple choice questions (Attempt all · 17 × 1 = 17)

1. An energy profile shows a very flat region after the first peak before rising to a second, higher peak; what does this suggest about the intermediate?

   1. It is highly reactive.

   2. It is consumed quickly.

   3. It is relatively stable.

   4. It has a high activation energy for the next step.

2. If absolute temperature of a gas is double and the pressure is reduced to one half, the volume of the gas will:

   1. Remain unchanged

   2. Increase four times

   3. Reduce to

   4.  Be doubled

3. Element is typically used to dope silicon to create a p-type semiconductor:

   1. Group 1 element

   2. Group 14 element

   3. Group 13 element

   4. Group 15 element

4. Which type of equilibrium involves a change of state?

   1. Chemical

   2. Physical

   3. Ionic

   4. Molecular

5. The order of reaction is:

   1. The total number of molecules taking part in the rate determining step

   2. The total number of molecules taking part in a chemical reaction

   3. Both a and b

   4. None of these

6. Which one of the following elements has the highest ionization energy?

   1. Sodium (Na)

   2. Magnesium (Mg)

   3. Aluminium (Al)

   4. Argon (Ar)

7. True about theoretical yield is:

   1. It is always less than actual yield

   2. It is always equal to actual yield

   3. It is always greater than actual yield

   4. It may be equal or less than actual yield

8. London dispersion forces increase with:

   1. Decreasing molar mass

   2. Increasing polarity

   3. Increasing molecular size

   4. Decreasing temperature

9. Which of the following factors would lead to a greater enthalpy change of hydration(more exothermic)?

   1. A larger ionic radius and a smaller charge

   2. A smaller ionic radius and a smaller charge

   3. A larger ionic radius and a larger charge

   4. A smaller ionic radius and a larger charge

10. Which one of the following have lowest vapour pressure at 25^oC?

    1. Water

    2. Ethyl alcohol

    3. Acetone

    4. Diethyl ether

11. Ionization energy for

    1. 738 kJ mol^-1

    2. 448 kJmol^-1

    3. 238 kJmol^-1

    4. 138 kJmol^-1

12. Which statement is true about a reversible reaction at equilibrium?

    1. All reactants are converted into products

    2. Microscopic changes stop

    3. The concentrations of products and reactants remain constant

    4. The reaction becomes irreversible

13. At the beginning the decrease in the concentration of reactants is:

    1. Slow

    2. Moderate

    3. Rapid

    4. None of these

14. Which property increases as you go down a group in the periodic table?

    1. Atomic radius

    2. Electron Affinity

    3. Electronegativity

    4. Ionization energy

15. Which of the following gases will occupy the same volume at STP if the masses are equal?

    1. O₂ and Cl₂

    2. CO₂ and N₂

    3. He and Ar

    4. All will differ

16. In VSEPR, lone pair-lone pair repulsion is:

    1. Stronger than bond pair-bond pair

    2. Equal to bond pair-bond pair

    3. Weaker than bond pair-lone pair

    4. Absent

17. If the calorie content of a food is given as 500 Calories, what does this value fundamentally represent in terms of energy change?

    1. The maximum work the body can derive from that food.

    2. The total heat released when food is completely metabolized.

    3. The change in internal energy of the food during digestion.

    4. The activation energy required to break down the food molecules.