(a) Explain briefly why \(^{4}_{2}\mathrm{He}\) has a stable electron configuration compared to \(^{9}_{4}\mathrm{Be}\)
(b) Consider the following elements: 1H and 3Li.
(i) State the number of electrons that an atom of each element would have after forming an ionic bond.
(ii) Give a reason for each of your answers stated in (b)(i).
(c) State two factors that should be considered when siting a chemical industry.
(d) State two advantages of using a catalyst instead of high temperatures in chemical reactions.
(e) Turpentine burns in chlorine according to the following equation:
\[ \mathrm{C}_{10}\mathrm{H}_{16(l)} + 8\mathrm{Cl}_{2(g)} \to 10\mathrm{C}_{(s)} + 16\mathrm{HCl}_{(g)} \]
Calculate the mass of turpentine that would completely burn in 21.3 g of chlorine.
[Molar mass of chlorine = \(71\ \mathrm{gmol}^{-1}\); Molar mass of Turpentine = \(136\ \mathrm{gmol}^{-1}\)]
(f) What is cracking?
(g) State two factors that may influence the value of electron affinity.
(h) What are carbohydrates?
(i) State two differences between a simple sugar and starch.
(j) Write an equation to show the dissociation of each of the following acids:
(i) \(\mathrm{H}_2\mathrm{CO}_3\);
(ii) \(\mathrm{CH}_3\mathrm{COOH}\).
(a) The stability of an atom's electron configuration is determined by the number of electrons in the outermost energy level. Helium has two electrons in its outermost energy level, which is the maximum number it can hold, so its electron configuration is stable. Beryllium, on the other hand, has four electrons in its outermost energy level, which is not stable, so it tends to lose or gain electrons to achieve stability.
(b)(i) An atom of hydrogen would have one electron, while an atom of lithium would have no electrons after forming an ionic bond.
(b)(ii) When hydrogen forms an ionic bond, it loses its single electron to become a positively charged ion (H+). Lithium, with three electrons in its outermost energy level, readily donates one electron to become a positively charged ion (Li+). This electron donation allows both elements to achieve a stable electron configuration.
(c) Two factors to consider when siting a chemical industry are access to raw materials and transportation infrastructure.
(d) Two advantages of using a catalyst instead of high temperatures in chemical reactions are that it reduces the energy required for the reaction and it can increase the selectivity of the reaction, meaning that it can produce more of the desired product and less of unwanted byproducts.
(e) To calculate the mass of turpentine that would completely burn in 21.3 g of chlorine, we need to use stoichiometry. First, we need to calculate the number of moles of chlorine present:
21.3 g Cl2 x (1 mol Cl2/71 g Cl2) = 0.3 mol Cl2
Next, we need to use the balanced chemical equation to determine the number of moles of turpentine needed to react with 0.3 mol Cl2:
8 mol Cl2 / 1 mol turpentine
0.3 mol Cl2 x (1 mol turpentine / 8 mol Cl2) = 0.0375 mol turpentine
Finally, we can use the molar mass of turpentine to convert the number of moles to mass:
0.0375 mol turpentine x 136 g/mol = 5.1 g turpentine
Therefore, 5.1 g of turpentine would completely burn in 21.3 g of chlorine.
(f) Cracking is the process of breaking down large hydrocarbons into smaller ones by breaking the carbon-carbon bonds in the molecules. This is typically done by heating the hydrocarbons to high temperatures in the presence of a catalyst.
(g) Two factors that may influence the value of electron affinity are the atomic radius and the effective nuclear charge. A smaller atomic radius and a higher effective nuclear charge will increase the attraction between the nucleus and electrons, leading to a higher electron affinity.
(h) Carbohydrates are a group of biomolecules that include sugars, starches, and cellulose. They are made up of carbon, hydrogen, and oxygen atoms and serve as a source of energy for living organisms.
(i) Simple sugars are monosaccharides, meaning they consist of a single sugar molecule, while starch is a polysaccharide, meaning it is made up of multiple
(a) The stability of an atom's electron configuration is determined by the number of electrons in the outermost energy level. Helium has two electrons in its outermost energy level, which is the maximum number it can hold, so its electron configuration is stable. Beryllium, on the other hand, has four electrons in its outermost energy level, which is not stable, so it tends to lose or gain electrons to achieve stability.
(b)(i) An atom of hydrogen would have one electron, while an atom of lithium would have no electrons after forming an ionic bond.
(b)(ii) When hydrogen forms an ionic bond, it loses its single electron to become a positively charged ion (H+). Lithium, with three electrons in its outermost energy level, readily donates one electron to become a positively charged ion (Li+). This electron donation allows both elements to achieve a stable electron configuration.
(c) Two factors to consider when siting a chemical industry are access to raw materials and transportation infrastructure.
(d) Two advantages of using a catalyst instead of high temperatures in chemical reactions are that it reduces the energy required for the reaction and it can increase the selectivity of the reaction, meaning that it can produce more of the desired product and less of unwanted byproducts.
(e) To calculate the mass of turpentine that would completely burn in 21.3 g of chlorine, we need to use stoichiometry. First, we need to calculate the number of moles of chlorine present:
21.3 g Cl2 x (1 mol Cl2/71 g Cl2) = 0.3 mol Cl2
Next, we need to use the balanced chemical equation to determine the number of moles of turpentine needed to react with 0.3 mol Cl2:
8 mol Cl2 / 1 mol turpentine
0.3 mol Cl2 x (1 mol turpentine / 8 mol Cl2) = 0.0375 mol turpentine
Finally, we can use the molar mass of turpentine to convert the number of moles to mass:
0.0375 mol turpentine x 136 g/mol = 5.1 g turpentine
Therefore, 5.1 g of turpentine would completely burn in 21.3 g of chlorine.
(f) Cracking is the process of breaking down large hydrocarbons into smaller ones by breaking the carbon-carbon bonds in the molecules. This is typically done by heating the hydrocarbons to high temperatures in the presence of a catalyst.
(g) Two factors that may influence the value of electron affinity are the atomic radius and the effective nuclear charge. A smaller atomic radius and a higher effective nuclear charge will increase the attraction between the nucleus and electrons, leading to a higher electron affinity.
(h) Carbohydrates are a group of biomolecules that include sugars, starches, and cellulose. They are made up of carbon, hydrogen, and oxygen atoms and serve as a source of energy for living organisms.
(i) Simple sugars are monosaccharides, meaning they consist of a single sugar molecule, while starch is a polysaccharide, meaning it is made up of multiple
