Crystallization separates a pure solid from a solution by cooling or evaporating the solvent. Impurities remain in the mother liquor. Example: purifying copper sulfate. Distillation for liquids; filtration for insoluble solids.
Explanation:
Urea (NH₂CONH₂) has molar mass 60, with 28 g N, percentage = (28/60)×100 ≈ 46.6%. Rounded to 46%. It is the most concentrated solid nitrogen fertilizer. Ammonium nitrate is 33%, ammonium sulfate 21%.
Explanation:
Phenolphthalein is a synthetic indicator that remains colorless in acidic and neutral solutions but turns pink/magenta in basic solutions. Methyl orange is red in acid and yellow in base. Litmus is red in acid and blue in base. Turmeric is yellow in acid and red in base.
Explanation:
Chadwick (1932) produced highly penetrating neutral radiation by bombarding Be with α-particles, identified as neutrons. Reaction: ⁹Be + ⁴He → ¹²C + ¹n.
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