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:
A bomb calorimeter burns a known mass of fuel in excess oxygen inside a sealed bomb immersed in water. The temperature rise of water is measured to calculate heat released. Thermometer is part of it but not the device itself.
Explanation:
Diamond is a giant covalent structure where each carbon is tetrahedrally bonded to four others via strong covalent bonds. Melting requires breaking numerous strong bonds, needing very high temperature (~3500°C). Graphite also has high melting point. Molecular solids like ice have low melting points. Carbon alone doesn't guarantee high m.p.; it's the structure.
Explanation:
Roasting involves heating sulfide ores in excess air to convert them to oxides and remove sulfur as SO₂. Example: 2ZnS + 3O₂ → 2ZnO + 2SO₂. Calcination is heating in absence of air (for carbonates/hydroxides). Smelting is reduction. Leaching uses chemicals.
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