(a) \( \mathrm{SiBr}_{4} \) tristorted tetrahedron (b) \( \mathrm{CS}_{2} \) trigonal pyramidal trigonal planar trigonal pyramidal (c) \( \mathrm{NO}_{3}^{-} \) trigonal planar bent trigonal pyramidal tetrahedral to

The density of \( \mathrm{SO}_{2} \) and \( \mathrm{CO}_{2} \) are \( 2.9 \mathrm{~g} / \mathrm{dm}^{3} \) and \( 1.98 \mathrm{~g} / \mathrm{dm}^{3} \) respectively. How much faster does \( \mathrm{CO}_{2} \) diffuse through a porous pot?

(a) \( \mathrm{SiBr}_{4} \) tristorted tetrahedron (b) \( \mathrm{CS}_{2} \) trigonal pyramidal trigonal planar trigonal pyramidal (c) \( \mathrm{NO}_{3}^{-} \) trigonal planar bent trigonal pyramidal tetrahedral to

Nếu một mẫu chất phóng xạ bắt đầu với 100g và giảm đi 12.5% mỗi giờ, tính khối lượng còn lại sau 4 giờ.

Using Dobereiner's law of triads, the missing number is \( \frac{\mathrm{Li}}{7}, \frac{\mathrm{Na}}{20}, \frac{\mathrm{~K}}{20} \).

Question B2 The following redox reaction is used in acidic solution in the Breathalyzer test to determine the level of alcohol in tl] blood of drunk drivers: \[ \mathrm{H}^{+}(\mathrm{aq})+\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}(\mathrm{aq})+\mathrm{C}_{2} \mathrm{H}_{5} \rightarrow \mathrm{Cr}^{3+}(\mathrm{aq})+\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O} \] a) Identify the elements undergoing changes in oxidation state and indicate the initial and final oxidation numbers for these elements. [5] b) Write and balance the oxidation half-reaction.[6] c) Write and balance the reduction half reaction.[6] d) Combine the half-reactions to produce a balanced redox reaction. [3]