Hm I’m confused, if you mean what are they weighting, it’s they :)
Mercury, Venus, Earth,Mars
Answer:
24 mol Cu
General Formulas and Concepts:
<u>Chemistry</u>
Explanation:
<u>Step 1: Define</u>
RxN: 2Cu (s) + O₂ (g) → 2CuO (s)
Given: 12 moles O₂
<u>Step 2: Stoichiometry</u>
<u />
= 24 mol Cu
<u>Step 3: Check</u>
<em>We are given 2 sig figs.</em>
Our final answer is in 2 sig figs, so no need to round.
250 --> 125 --> 62.5 --> 31.25
each arrow equals one half life, so 3 half lives
14 days/ 3 half lives =
4.67 days = half life
Answer is: pH of solution is 5,17.
Kb(NH₃) = 1,8·10⁻⁵.
c(NH₄Cl) = 0,084 M = 0,084 mol/L.
Chemical reaction: NH₄⁺ + H₂O → NH₃ + H₃O⁺.
Ka · Kb = 10⁻¹⁴.
Ka(NH₄⁺) = 10⁻¹⁴ ÷ 1,8·10⁻⁵.
Ka(NH₄⁺) = 5,55·10⁻¹⁰.
[H₃O⁺] = [NH₃] = x.
Ka(NH₄⁺) = [H₃O⁺] · [NH₃] ÷ [NH₄⁺].
5,55·10⁻¹⁰ = x² ÷ (0,084 M - x).
Solve quadratic equation: x = [H₃O⁺] = 6,8·10⁻⁶ M.
pH = -log[H₃O⁺].
pH = -log(6,8·10⁻⁶ M) = 5,17.
