Alkenes contain at least one carbon-carbon double bond. The simplest alkene is ethene (C₂H₄). Methane is an alkane; ethane is an alkane; propyne is an alkyne. General formula for alkenes: CₙH₂ₙ.
Explanation:
Calcium (Ca) has a valency of +2, and the phosphate ion (PO₄) has a valency of -3. To balance the charges, we need three calcium ions and two phosphate ions, giving the formula Ca₃(PO₄)₂. This is determined by criss-crossing the valencies of the constituent ions.
Explanation:
Baking powder contains sodium bicarbonate (NaHCO₃) and a weak solid acid such as tartaric acid or cream of tartar (potassium hydrogen tartrate). When moistened, they react to produce CO₂, making dough rise. Baking soda alone requires an acidic ingredient (yogurt, lemon). The acid in baking powder ensures reliable leavening. Sodium chloride and calcium carbonate do not serve this purpose.
Explanation:
Chlorophyll, the green pigment in plants, contains a magnesium ion (Mg²⁺) at the center of the porphyrin ring. It's essential for photosynthesis. Haemoglobin in blood contains iron. Calcium is in bones. Sodium is in body fluids.
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