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*IJMB CHEMISTRY* *12(a) Empirical + molecular formula* Mass C = 0.120g, H = 0.02g. Mass O = 0.30 - 0.12 - 0.02 = 0.16g Moles: C = 0.12/12 = 0.01; H = 0.02/1 = 0.02; O = 0.16/16 = 0.01 Ratio C:H:O = 0.01:0.02:0.01 = 1:2:1 → *Empirical formula: CH₂O* Empirical mass = 12+2+16 = 30 Molar mass = 180 → n = 180/30 = 6 *Molecular formula: C₆H₁₂O₆* → Glucose *12(b) Products* (i) Ethanamide + P₄O₁₀ → *Ethanenitrile CH₃CN* + water (ii) Ethanamide + HNO₂ → *Ethanoic acid CH₃COOH* + N₂ + H₂O (iii) Ethanamide + Br₂ + KOH → *Methylamine CH₃NH₂* - Hofmann bromamide reaction (iv) Ethanamide + LiAlH₄ → *Ethanamine CH₃CH₂NH₂* (v) Ethanamide + HCl/H₂O → *Ethanoic acid CH₃COOH* + NH₄Cl

*IJMB CHEMISTRY II* *NUMBER NINE* (9) (i) Hexane - C₆H₁₄ (ii) Heptane - C₇H₁₆ (iii) Octane - C₈H₁₈ (iv) Nonane - C₉H₂₀ (v) Decane - C₁₀H₂₂

No 11

*IJMB CHEMISTRY II* *QUESTION FOUR* (4ai) Stereoisomers are compounds having the same molecular formula and structural formula but differ in the three-dimensional spatial arrangement of atoms or groups within the molecule, thereby giving rise to different properties. (ii) They can be distinguished by their optical activity. One stereoisomer rotates plane-polarized light in a clockwise direction while the other rotates it in an anticlockwise direction. (4b) When alanine and glycine react, condensation reaction occurs with elimination of water, leading to formation of two dipeptides: Alanyl-glycine H₂N–CH(CH₃)–CO–NH–CH₂–COOH Glycyl-alanine H₂N–CH₂–CO–NH–CH(CH₃)–COOH

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*IJMB- ISLAMIC* (1) Idol Worshipping in Pre-Islamic Arabia Idol worship in Arabia developed gradually from the original monotheism established by Prophets Ibrahim and Ismail, who built the Kaabah as a house of worship for the One God. According to the hadith tradition, the man credited with introducing idolatry into Arabia was Amr ibn Luhayy al-Khuza'i, chief of the Khuza'ah tribe, who brought an idol called Hubal from the Levant and placed it inside the Kaabah, also institutionalizing practices like the Bahirah and Sa'ibah (dedicating certain animals to idols). By the time of the Prophet's birth, idolatry had spread widely: (i) Hubal — the chief idol housed inside the Kaabah itself, made of red agate, used for divination through arrows (al-azlam). (ii) Al-Lat, Al-Uzza, and Manat — the three most prominent goddesses, mentioned in the Qur'an (Surah An-Najm), worshipped respectively at Ta'if, near Mecca, and between Mecca and Medina. (iii) Wadd, Suwa', Yaghuth, Ya'uq, and Nasr — older idols mentioned in Surah Nuh as having been worshipped even before the Flood, later reintroduced into Arab worship. Tradition records roughly 360 idols surrounding the Kaabah, one for almost every day of the lunar year. The nature of this worship was not a denial of Allah as Creator — the Qur'an itself records that the pagan Arabs acknowledged Allah as the ultimate Creator and Sustainer (Surah Az-Zumar 39:3, Surah Al-Ankabut 29:61) — but they took the idols as intermediaries (intercessors) believed to bring them closer to Allah. Each tribe often had its own idol, kept either at home or at shrines; idol worship also involved animal sacrifice, circumambulation (tawaf), and offerings, and was tied closely to tribal identity, the pilgrimage economy of Mecca, and the political authority of the Quraysh as custodians of the Kaabah. Stones and trees were also venerated in some cases, such as the tree known as Dhat Anwat.

*IJMB CHEMISTRY I* *NUMBER SEVEN* (7) (i) They have one valence electron: Each Group 1 element has only one electron in its outermost shell, which they readily lose during chemical reactions. (ii) They are highly reactive metals: They react vigorously with water, oxygen, and other non-metals. Their reactivity increases down the group. (iii) They form positive ions (+1): Since they lose one electron easily, they form univalent cations with a charge of +1. (iv) They are soft and have low densities: Group 1 metals are soft enough to be cut with a knife and are generally less dense than most other metals. (v) They form alkaline hydroxides: When they react with water, they produce soluble hydroxides that are strongly alkaline, which is why they are called alkali metals.

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*IJMB CHEMISTRY I* *NUMBER NINE* (9a) The inert pair effect is the tendency of the outermost s-electrons (ns² electrons) in heavier elements to remain unshared or inactive in chemical bonding. As a result, these electrons do not participate readily in bond formation, leading to the stability of lower oxidation states. (9bi) NH₃ Let the oxidation state of N = x x + 3(+1) = 0 x + 3 = 0 x = -3 ∴ Oxidation state of nitrogen = –3 (9bii) NH₂OH Let the oxidation state of N = x x + 3(+1) + (-2) = 0 x + 1 = 0 x = -1 ∴ Oxidation state of nitrogen = –1 (9biii) N₂ Since N₂ is an element in its free state, its oxidation state is 0. ∴ Oxidation state of nitrogen = 0

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No 7