Stratospheric ozone absorbs harmful UV-B and UV-C radiation from the sun, protecting living organisms. Depletion by CFCs increases UV at surface. Infrared is absorbed by greenhouse gases.
Explanation:
Roasting is the process of heating the concentrated ore (usually sulfide ores) strongly in the presence of excess air below its melting point. It converts the ore to its oxide form and removes volatile impurities as gases (e.g., 2ZnS + 3O₂ → 2ZnO + 2SO₂).
Explanation:
After each half-life, half of the remaining atoms decay. Number of half-lives n = total time / half-life = 30/10 = 3. Fraction remaining = (1/2)ⁿ = (1/2)³ = 1/8. Thus 12.5% remains. Radioactive decay follows first-order kinetics. Exam trick: fraction remaining = (0.5)^(t/T), where T is half-life. After 4 half-lives, 1/16 remains.
Explanation:
Ionic compounds consist of positive and negative ions held together by strong electrostatic forces of attraction (ionic bonds). A large amount of energy is required to overcome these forces, resulting in high melting and boiling points. They also conduct electricity when molten or in solution.
No comments yet. Be the first to start the discussion!