List of practice Questions

Can you attempt building models of biomolecules using commercially available atomic models (Ball and Stick models).

Emission transitions in the Paschen series end at orbit n = 3 and start from orbit n and can be represented as v = 3.29 × 10¹⁵ (Hz) [\(\frac{1}{3^2}-\frac{1}{n^2}\)] Calculate the value of n if the transition is observed at 1285 nm. Find the region of the spectrum.

One mole of H₂O and one mole of CO are taken in 10 L vessel and heated to 725 K. At equilibrium 40% of water (by mass) reacts with CO according to the equation,
\(H_2O (g) + CO (g) ⇋ H_2 (g) + CO_2 (g)\)
Calculate the equilibrium constant for the reaction.

Explain the composition of triglyceride.

Calculate the wavelength for the emission transition if it starts from the orbit having radius of 1.3225 nm and ends at 211.6 pm. Name the series to which this transition belongs and the region of the spectrum.

Dual behaviour of matter proposed by de Broglie led to the discovery of electron microscope often used for the highly magnified images of biological molecules and other type of material. If the velocity of the electron in this microscope is 1.6 × 106 ms–1, calculate de Broglie wavelength associated with this electron.

What is the equilibrium concentration of each of the substances in the equilibrium when the initial concentration of \(ICl\) was \(0.78 \ M\)?
\(2ICl (g) ⇋ I_2 (g) + Cl_2 (g); \ K_c = 0.14\)

K_p = 0.04 atm at 899 K for the equilibrium shown below. What is the equilibrium concentration of C₂H₆ when it is placed in a flask at 4.0 atm pressure and allowed to come to equilibrium?
\(C_2H_6 (g) ⇋ C_2H_4 (g) + H_2 (g)\)

Find and write down structures of 10 interesting small molecular weight biomolecules. Find if there is any industry which manufactures the compounds by isolation. Find out who are the buyers.

What is a centromere? How does the position of centromere form the basis of classification of chromosomes. Support your answer with a diagram showing the position of centromere on different types of chromosomes.

Is there any change in the hybridisation of B and N atoms as a result of the following reaction? 
\(BF_3+ NH_3 \rightarrow F_3B.NH_3\)

Draw diagrams showing the formation of a double bond and a triple bond between carbon atoms in \(C_2H_4\) and \(C_2H_2\) molecules.

What is the total number of sigma and pi bonds in the following molecules?

1. \(C_2H_2\) 
2. \(C_2H_4\)

Describe the structure of the following with the help of labelled diagrams.
(i) Nucleus
(ii) Centrosome

The electron energy in hydrogen atom is given by \(E_n = \frac {(–2.18×10^{–18})}{n^2} \ J\). Calculate the energy required to remove an electron completely from the n = 2 orbit. What is the longest wavelength of light in cm that can be used to cause this transition?

Chlorine is used to purify drinking water. Excess of chlorine is harmful. The excess of chlorine is removed by treating with sulphur dioxide. Present a balanced equation for this redox change taking place in water.

Similar to electron diffraction, a neutron diffraction microscope is also used for the determination of the structure of molecules. If the wavelength used here is 800 pm, calculate the characteristic velocity associated with the neutron.

In Ostwald's process for the manufacture of nitric acid, the first step involves the oxidation of ammonia gas by oxygen gas to give nitric oxide gas and steam. What is the maximum weight of nitric oxide that can be obtained starting only with 10.00 g. of ammonia and 20.00 g of oxygen?

Name two cell-organelles that are double membrane bound. What are the characteristics of these two organelles? State their functions and draw labelled diagrams of both.

Calculate the wavelength of an electron moving with a velocity of \(2.05×10^7 \ ms^{–1}\).

The mass of an electron is 9.1 × 10^–31 kg. If its K.E. is 3.0 × 10^–25 J, calculate its wavelength.

Consider the reactions: 
(a) \(6 \,CO_2(g) + 6H_2O(l) \rightarrow C_6H_{12}O_6(aq) + 6O_2(g)\) 
(b) \(O_3(g) + H_2O_2(l) \rightarrow  H_2O(l) + 2O_2(g)\) 
Why it is more appropriate to write these reactions as: (a) \(6\,CO_2(g) + 12H_2O(l) \rightarrow  C_6H_{12}O_6(aq) + 6H_2O(l) + 6O_2(g)\) 
(b) \(O_3(g) + H_2O_2(l) \rightarrow H_2O(l) + O_2(g) + O_2(g)\) 
Also suggest a technique to investigate the path of the above (a) and (b) redox reactions.

Which hybrid orbitals are used by carbon atoms in the following molecules? 

1. \(CH_3-CH_3\); 
2. \(CH_3-CH=CH_2\); 
3. \(CH_3-CH_2-OH\); 
4. \(CH_3-CHO\) 
5. \(CH_3COOH\)

How many electrons in an atom may have the following quantum numbers?

1. n = 4, m_s = – \(\frac 12\)
2. n = 3, l = 0

What do you understand by bond pairs and lone pairs of electrons? Illustrate by giving one example of each type.