Chemistry Test - 7

The law, which states that at constant temperature, the volume of a given mass of gas is inversely proportional is pressure, is known as Boyles law. As per Boyle's law, any change in the volume occupied by a gas (at constant quantity and temperature) will result in a change in the pressure exerted by it. In other words, the product of the initial pressure and the initial volume of a gas is equal to the product of its final pressure and final volume (at constant temperature and number of moles). This law can be expressed mathematically as follows:

\(P_{1} V_{1}=P_{2} V_{2}\)

Where,

- \(P_{1}\) is the initial pressure exerted by the gas

- \(V_{1}\) is the initial volume occupied by the gas

- \(P_{2}\) is the final pressure exerted by the gas

- \(V_{2}\) is the final volume occupied by the gas

The atomic number is equal tonumber of protons \(= 16\). The element issulphur (S).

Atomic mass number \(=\) number ofprotons \(+\) number of neutrons

\(= 16 + 16 = 32\)

Species is not neutral as the number ofprotons is not equal to electrons. It isanion (negatively charged) with chargeequal to excess electrons \(= 18 – 16 = 2\)

Thus symbol is \({ }_{16}^{32} \mathrm{~S}^{2-}\).

The atomic and ionic radii increase as the atomic number increases. This is because the number of electron shells has increased. As the halogen atom forms the halide ion by gaining one electron, so radius of the halide ion is always greater than that of the corresponding halogen atom.

Positive Beilstein shows that halogens may be present. A positive Beilstein’s test for halogens does not always indicate the presence of halogen since some halogen-free compounds viz. urea, thiourea, amides etc. also respond this test. The reason being the fact that these halogen-free compounds form cuprous cyanide which is volatile and decomposes to copper which burns with green flame.

A complex has the molecular formula \(\mathrm{Co} .5 \mathrm{NH}_{3} . \mathrm{NO}_{2} . \mathrm{Cl}_{2}\). One mole of this complex produces three moles of ions in an aqueous solution. On reacting this solution with excess of \(\mathrm{AgNO}_{3}\) solution, we get 2 moles of white ppt. The complex is\(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{NO}_{2}\right] \mathrm{Cl}_{2}\).

\(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{NO}_{2}\right] \mathrm{Cl}_{2}\) can form three ions, one \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{NO}_{2}\right]^{2+}\) and two \(\mathrm{Cl}^{-}\)ions.

As 1 mole of complex gives 2 moles of \(\mathrm{Cl}^{-}\)ions, 2 moles of AgCI will be precipitated.

Aspartamecan be only used in soft drinks. It is an artificial sweetening agent which is unstable at higher temperatures. It is a compound formed from aspartic acid and phenylalanine. It is 100 times as sweet as cane sugar.

Glycogen is a polymer of glucose. Glycogen is a substance which is deposited in body tissues in the form of carbohydrates and it is broken down in the form of glucose which provides an instant source of energy to muscles by the process of glycolysis. It is accumulated in response to insulin and it is broken down into glucose in response to glucagon and it is mainly stored in the liver and the muscles. It provides the body with an instant source of energy when the blood glucose level decreases. It maintains blood glucose level and it is really important because glucose is the only fuel used by the brain virtually.

If we place an element with atomic number 115 in the periodic table, it will come under the 15^th group. So, it will be a p-block element.

We know that for a first order reaction:-

Rate = k[R]

\(\therefore 1.5 \times 10^{-2} \mathrm{M} \min ^{-1}=\mathrm{k}[0.5 \mathrm{M}]\)

\(\Rightarrow \mathrm{k}=\frac{1.5 \times 10^{-2} \mathrm{M} / \mathrm{min}}{0.5 \mathrm{M}}\)

\(\Rightarrow \mathrm{k}=0.03 \mathrm{~min}^{-1}\)

We also know that, half life of a first order reaction:

\(\mathrm{t} \frac{1 } 2=\frac{ln (2)}{\mathrm{k}}\)

\(=\frac{0.693}{\mathrm{k}}\)

\(=\frac{0.693}{0.03 \mathrm{~min}^{-1}}\)

\(=23.1 \) min

Ethane is an example of a saturated carbon compound.Saturated hydrocarbons are carbon compound that contains only single bonds between carbon atoms.Ethane is a colourless, odourless gas.Ethane is isolated on an industrial scale from natural gas and as a petrochemical by-product of petroleum refining.The chemical formula of Ethane is \(\mathrm{C}_{2} \mathrm{H}_{6}\).Ethane can be found underground in liquid form in rock formations.