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]

Select the single best answer. Which of the following describes the bonding in the hydrogen cyanide molecule, HCN? As N is \( s p \)-hybridized. C uses \( s p \) hybridized orbitals in bonding. C uses \( s p^{2} \) hybridized orbitals in bonding. C uses \( s p^{3} \) hybridized orbitals in bonding. C uses \( s p^{3} d \) hybridized orbitals in bonding.

c. 5-etil-5metil-1,3-ciclohexadieno

Es el nombre correcto del compues \( \mathrm{CH}_{5}-\mathrm{CH}_{2}-\mathrm{C} \equiv \mathrm{C}-\mathrm{C} \equiv \mathrm{C}-\mathrm{C} \) a. \( 3,5,7 \) decatrino b. \( 3,5,7 \) decino c. \( 4,6,8 \) decino d. \( 4,6,8 \) decatrino

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.

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]