Science (English Medium) इयत्ता ११ - CBSE Question Bank Solutions for Chemistry

Arrange the following type of radiations in increasing order of frequency:

1. radiation from microwave oven
2. amber light from traffic signal
3. radiation from FM radio
4. cosmic rays from outer space and
5. X-rays.

Nitrogen laser produces radiation at a wavelength of 337.1 nm. If the number of photons emitted is 5.6 × 10²⁴, calculate the power of this laser.

Neon gas is generally used in the signboards. If it emits strongly at 616 nm, calculate

1. the frequency of emission,
2. distance traveled by this radiation in 30 s
3. energy of quantum and
4. number of quanta present if it produces 2 J of energy.

Although both CO₂ and H₂O are triatomic molecules, the shape of H₂O molecule is bent while that of CO₂ is linear. Explain this on the basis of dipole moment.

Write the significance/applications of dipole moment.

Define electronegativity.

How does electronegativity differ from electron gain enthalpy?

Explain with the help of suitable example polar covalent bond.

Arrange the bonds in order of increasing ionic character in the molecules: LiF, K₂O, N₂, SO₂ and ClF₃.

Which out of NH₃ and NF₃ has higher dipole moment and why?

At 0°C, the density of a certain oxide of a gas at 2 bar is same as that of dinitrogen at 5 bar. What is the molecular mass of the oxide?

The pressure of 1 g of an ideal gas A at 27 °C is found to be 2 bar. When 2 g of another ideal gas B is introduced in the same flask at the same temperature the pressure becomes 3 bar. Find a relationship between their molecular masses.

The drain cleaner, Drainex contains small bits of aluminum which react with caustic soda to produce dihydrogen. What volume of dihydrogen at 20 °C and one bar will be released when 0.15g of aluminum reacts?

The density of a gas is found to be 5.46 g/dm³ at 27 °C at 2 bar pressure. What will be its density at STP?

How much time would it take to distribute one Avogadro number of wheat grains, if 10¹⁰ grains are distributed each second?

The enthalpies of all elements in their standard states are ______.

The reaction of cyanamide, NH₂CN_(s), with dioxygen was carried out in a bomb calorimeter, and ΔU was found to be −742.7 kJ mol⁻¹ at 298 K. Calculate enthalpy change for the reaction at 298 K.

\[\ce{NH_2 CN(g) + 3/2 O_2(g) -> N_2(g) + CO_2(g) + H_2O(l)}\]

Calculate the enthalpy change on freezing of 1.0 mol of water at 10.0°C to ice at - 10.0°C. Δ_fusH = 6.03 kJ mol^-1 at 0°C.

C_p[H₂O(l)] = 75.3 J mol^-1 K^-1

C_p[H₂O(s)] = 36.8 J mol^-1 K^-1

Enthalpy of combustion of carbon to CO₂ is –393.5 kJ mol^–1. Calculate the heat released upon formation of 35.2 g of CO₂ from carbon and dioxygen gas.

Enthalpies of formation of CO_(g), CO_2(g), N₂O_(g) and N₂O_4(g) are -110 kJ mol^-1, - 393 kJ mol^-1, 81 kJ mol^-1 and 9.7 kJ mol^-1 respectively. Find the value of Δ_rH for the reaction:

\[\ce{N2O_{4(g)} + 3CO_{(g)} → N2O_{(g)} + 3CO_{2(g)}}\]