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Original length = 20m first new length = 20.01m first increase in length = 20.01m - 20m = 0.01m Second new length = 20.05m second increase in length = 20.05 - 20m = 0.05m From hooke's law = \( \frac{F_1}{e_1} = \frac{F_2}{e_2}\) \(\implies \frac{50}{0.01} = \frac{F_2}{0.05}\) \(\implies F_2 = \frac{50 \times 0.05}{0.01} = 250N \)

Evaporation is a change of state from a liquid to a gas. Distillation is a physical process that involves a phase change from liquid to gas (vapour) and then back to liquid. Crystallization is a physical change that occurs when a substance turns from a liquid to a solid crystal. Sublimation is a change of state from a solid to a gas without passing through a liquid state.

Chemical reactions always involve the formation of new substances. This is because chemical reactions change the arrangement of atoms in a substance, which creates new substances with different chemical properties.

Equation of the reaction H\(_2\)SO\(_4\)(g) + CuO(s) → CuSO\(_4\)(aq) + H\(_2\)O Relative molecular mass of H\(_2\)SO\(_4\) = 1 + 2 + 32 + 16 + 4 = 98 Relative molecular mass of CuO = 64 + 16 =80 From the above equation, 98g of H\(_2\)SO\(_4\) reacts with 80g of CuO. ∴ 4.9g of H\(_2\)SO\(_4\) will react with Xg of CuO = (4.9 * 80)/98 of CuO = 392/98 = 4.0g Alternatively, H\(_2\)SO\(_4\)(g) + CuO(s) → CuSO\(_4\)(aq) + H\(_2\)O 1 : 1 Since the combining ratio of H\(_2\)SO\(_4\) and CuO is in ratio 1:1, the number of moles will also be equal. Hence, we can first calculate the amount of H\(_2\)SO\(_4\), since we were given the mass of H\(_2\)SO\(_4\) that reacted as 4g and the Molecular mass is 98g/mol Amount of moles of H\(_2\)SO\(_4\) = \(\frac{mass}{Molecular mass}\) = \(\frac{4.9}{98}\) = 0.05 mole Amount of moles of CuO = \(\frac{mass}{Molecular mass}\) 0.05 = \(\frac{mass}{64 + 16}\) Mass = 0.05 x 80 = 4.0g

According to Charles's Law, the volume of a gas would be zero at absolute zero, which is - 273^\circC or 0 Kelvin. The Volume is of gas is zero at absolute zero of temperature. On the Celsius scale, zero is the temperature at which water freezes.

Applying the Graham's law definition; i.e, \(\frac{RSO_2}{RCH_4}\) = \(\sqrt{\frac{MCH_4}{MSO_2}}\) \(\frac{tSO_2}{tCH_4}\) = \(\sqrt{\frac{MSO_2}{MCH_4}}\) (rate of diffusion ∝ \(\frac{1}{time taken}\)) Where t(SO\(_2\)) = ?, M(SO\(_2\)) = 64 t(CH\(_4\)) = 20 sec, M(CH\(_4\)) = 16 Therefore, \(\frac{t(SO_2)}{20}\) = \(\sqrt{\frac{64}{16}}\) \(\frac{t(SO_2)}{20}\) = \(\frac{8}{4}\) t(SO\(_2\)) = 8 x \(\frac{20}{4}\) = 40 sec.

When an electron is added to a halogen atom, it will have eight valence electrons. Halogens have seven valence electrons in their outermost shell. When an electron is added to a halogen atom, it fills its outermost shell, resulting in a full valence shell of 8 electrons.

The shape of an s-orbital is spherical. S-orbitals are spherically symmetric, meaning that the wave function only depends on the distance from the nucleus, not the direction. The s-orbital is spherical due to its lack of angular dependence and zero angular momentum (l=0), meaning the probability of finding an electron is the same in all directions from the nucleus.

\alpha - particle is represented by He atom with mass number of 4 and atomic number of 2. Thus, try to balance the mass number and atomic number of both Ra and Rn by subtracting 4 from 226 i.e (226 - 4) and subtracting 2 from 88 i.e (88 - 2 = 86 ). \(^{226}\)\(_{88}\)Ra → \(^{222}\)\(_{86}\)Rn + \(^4\)\(_2\)He (\alpha - particle)

Electronegativity is the tendency of an atom to attract electrons when forming a chemical bond. In HCl, the chlorine atom's higher electronegativity causes it to attract the bonding electrons, resulting in a partial negative charge on chlorine and a partial positive charge on hydrogen.

Two isotopes of Chlorine are : \(^{35}\)Cl and \(^{37}\)Cl Atomic mass of Cl : 35.5 Ratio of the isotopes of Chlorine : 3 : 1 Let the relative atomic abundance of \(^{37}\)Cl = 1 x X = X Let the relative atomic abundance of \(^{35}\)Cl = 3 x X = 3X N.B : The average atomic mass = sum of products of each isotope mass and its relative abundance. A.M.M = (3x of 35) + (x of 37) 35.5 = (3x X 35) + (x X 37) 35.5 = 105x + 37x 35.5 = 142x x = \(\frac{35.5}{142}\) x = 0.25 Convert to percentage. Recall that relative atomic abundance of \(^{37}\)Cl = x = 0.25 x 100 = 25% and the relative atomic abundance of \(^{35}\)Cl = 3X = 3(0.25) = 0.75 x 100 = 75% We were asked for the Relative abundance of isotope of mass number 37 i.e \(^{37}\)Cl is 25% Alternatively, Ratio of the isotopes of Chlorine : 3 : 1 Sum of ratios = 3 + 1 = 4 Relative Abundance of Cl isotopes = % ratio of \(^{35}\)Cl and % ratio of \(^{37}\)Cl = \(\frac{3}{4}\)x 100 and \(\frac{1}{4}\) x 100 = 75% \(^{35}\)Cl and 25% \(^{37}\)Cl Relative abundance of \(^{37}\)Cl = 25

When heated, a mixture of hydrogen and neon gases emits light and burns in a flame.When heated, the atoms in the gas absorb energy, causing the electrons to jump to higher energy levels. When the electrons return to their original energy levels, they emit light. A mixture of helium and nitrogen does not burn in a flame because both helium and nitrogen are non-flammable. A mixture of helium and neon does not burn in a flame because helium and neon are non-reactive. A mixture of neon and nitrogen will not burn in a flame because neither neon nor nitrogen are flammable.

Water hardness is caused by the presence of positively charged metallic ions, most commonly calcium and magnesium. Water becomes hard when it comes into contact with limestone and other rocks that contain calcium compounds. For example, rainwater that flows over rocks on its way to a reservoir can pick up calcium and magnesium ions.

Acidic conditions can increase the solubility of metal ions in soil, thereby allowing them to leach into groundwater. Also, trioxonitrate(v) salts are generally the only soluble salts of some metals. All trioxonitrate(v) salts are soluble in water. However, nitrates can also contribute to water pollution, but they're more commonly associated with eutrophication and health issues rather than directly mobilizing metal ions. Consequently, acidity plays a significant role in mobilizing metal ions, making them more likely to contaminate groundwater.

Carcinogenic substances, also known as carcinogens, are agents that can cause cancer. Examples include tobacco smoke, alcohol, asbestos, and certain chemical compounds like benzene and asbestos. Asbestos is generally considered more carcinogenic than sawdust. Asbestos, particularly the amphibole fibers, is a known human carcinogen and has been linked to mesothelioma, lung cancer, and other cancers. While wood dust is also classified as a human carcinogen, primarily associated with nasal cancer, the carcinogenic potential of asbestos is considered higher.