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Questions in chemistry

[Answered] The pOH of a solution is 6.0. Which statement is correct? Use [tex]$pOH =-\log \left[ OH ^{-}\right]$[/tex] and [tex]$pH + pOH =14$[/tex]. A. The pH of the solution is 20.0. B. The concentration of [tex]$OH ^{-}$[/tex] ions is [tex]$1.0 \times 10^{-8} M$[/tex]. C. The concentration of [tex]$OH ^{-}$[/tex] ions is [tex]$1.0 \times 10^6 M$[/tex]. D. The pH of the solution is 8.0.

[Answered] Select the correct answer from each drop-down menu. Mendeleev's table of elements was better accepted than those of other scientists at the time because [...]. Moseley went a step further in suggesting that the elements be arranged according to [...].

[Answered] Select the correct answer. The half reaction of an oxidation-reduction reaction shows that iron gains electrons. What does this electron gain mean for iron? A. It is neutralized. B. It is oxidized. C. It is reduced. D. It has dissolved. E. It has precipitated.

[Answered] A chemical equation lists NaHCO3(s) as a reactant. What does (s) indicate? A. The compound is a solid. B. The compound is a liquid. C. The compound is a gas. D. The compound is dissolved in water.

[Answered] Which of the following compounds is the most stable? A. AgCl B. $CuCl _2$ C. $AlCl _3$ D. LiCl

[Answered] Which represents the balanced nuclear equation for the beta minus decay of Co-60? ${ }_{27}^{60} Co \longrightarrow{ }_{26}^{60} Fe +{ }_{+1}^0 e$ ${ }_{27}^{60} Co \longrightarrow{ }_{28}^{60} Ni +{ }_{-1}^0 e$ ${ }_{27}^{80} Co +{ }_{+1}^0 e \longrightarrow{ }_{26}^{60} Ni$ ${ }_{27}^{60} Co +{ }_{-1}^0 e \longrightarrow{ }_{26}^{60} Fe

[Answered] Select the correct answer from each drop-down menu. Mendeleev's table of elements was better accepted than those of other scientists at the time because Moseley went a step further in suggesting that the elements be arranged according to

[Answered] Select the best answer for the question. 14. On the pH scale, which value is considered neutral? A. 5 B. 7 C. 2 D. 11

[Answered] Select the correct answer. The half reaction of an oxidation-reduction reaction shows that iron gains electrons. What does this electron gain mean for iron? A. It is neutralized. B. It is oxidized. C. It is reduced. D. It has dissolved. E. It has precipitated.

[Answered] Niobium-91 has a half-life of 680 years. After 2,040 years, how much niobium-91 will remain from a $300.0-g$ sample? A. 3 g B. 18.75 g C. 37.5 g D. 100.0 g