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.

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?

Question B 2 The following redox reaction is used in acidic solution in the Breathalyzer test to determine the level of alcohol in th 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 theseelements.

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

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.