Chemistry Test-10

Benzene, Toluene, Carbon tetrachloride compounds are toxic.

Hund's rule:

• Every orbital in a sublevel is singly occupied before any orbital is doubly occupied.
• All of the electrons in singly occupied orbitals have the same spin (to maximize total spin).

According to Hund's rule we will fill the orbitals with a single electron then start filling it in both the spins.

That's why the electronic configuration of

Nitrogen is [He] 2s² 2px¹2py¹2pz¹

and not[He] 2s² 2px²2py¹2pz⁰.

Mole fraction is the number of moles of part over total moles \(\mathrm{OR}\)

\(\text { Mole fraction }=\frac{\text { Number of moles of a solute }}{\text { Total number of moles in solution }}\)

If for example, we take that number of moles of solute as \(\mathrm{n}_1\) and that of solvent is \(\mathrm{n}_2\)

Then, Mole fraction of solute \(=\frac{n_1}{n_1+n_2}\)

Mole fraction of solvent \(=\frac{\mathrm{n}_2}{\mathrm{n}_1+\mathrm{n}_2}\)

Then, sum of mole fractions will be \(=\frac{\mathrm{n}_1}{\mathrm{n}_1+\mathrm{n}_2}+\frac{\mathrm{n}_2}{\mathrm{n}_1+\mathrm{n}_2}=1\)

An equilibrium system that contains products and reactants in a single phase is a homogeneous equilibrium; a system whose reactants, products, or both are in more than one phase is a heterogeneous equilibrium.

Saponins also referred to selectively as triterpene glycosides, are bitter-tasting usually toxic plant-derived organic chemicals that have a foamy quality when agitated in water. They are used in soaps, medicinals, fire extinguishers, speciously as dietary supplements, for the synthesis of steroids, and in carbonated beverages (the head on a mug of root beer).

As we know,

\(E_{c e l l}=E_{c e l l}^{0}-\frac{0.0591}{n} \log Q\)

Given,

\(\mathrm{Zn}(\mathrm{s})+\mathrm{Cu}^{2+}(0.1 \mathrm{M}) \rightarrow \mathrm{Zn}^{2+}(1 \mathrm{M})+\mathrm{Cu}(\mathrm{s})\)

\(Q=\frac{\left[Z n^{2+}\right]}{\left[C u^{2+}\right]}=\frac{1}{0.1}=10\)

\(E_{c e l l}=1.10-\frac{0.0591}{2} \log 10\)

\(E_{c e l l}=1.10-0.0295\)

\(E_{c e l l}=1.0705 \mathrm{~V}\)

Volume of \(0.5\) mole of steam at \(1 atm\) pressure

\(=\frac{ nRT }{ P }=\frac{0.5 \times 0.0821 \times 373}{1.0}=15.3 L\)

Change in volume \(=\) vol. of steam \(-\) vol. of water \(=15.3-\)negligible \(=15.3 L\)

Work done by the system,

\( = P _{\text {ext }} \times \text { volume change }\)

\(=1 \times 15.3=15.3 \text { litre-atm } \)

\( =15.3 \times 101.3 J =1549.89 J\)

'W' should be negative as the work has been done by the system on the surroundings.

W \(\mathrm{=-1549.89 J =-1.54 kJ}\)

If an element has seven electrons in its outermost shell then it is likely to have smallest the atomic size among all the elements in the same period.

As we go from left to right in a period as the atomic radii decreases as the electrons are added to the same valence shell. The nuclear attraction decreases and hence the element shrinks. So, element with \(7\) electrons in its valence shell will have smallest atomic size.

Except artificial silk, all others are made up of polyamides.

Let V litre of 10 N HCl be mixed with (1 - V) litre of 4 N HCl to give (V + 1 - V) = 1 L of 7N HCl

As we know that,

\(N_{1} V_{1}+N_{2} V_{2}=N V\)

\(10 V+4(1-V)=7 \times 1\)

\(10 V+4-4 V=7\)

\(6 V=7-4\)

\(V=\frac{3}{6}=0.50 L\)

Volume of \(10 \mathrm{NHCl}=0.50 \mathrm{~L}\)

Volume of \(4 \mathrm{NHCl}=1-0.50=0.50 L\)