Answer:
118 mL
Explanation:
We can easily calculate the final volume of the solution (V₂) by applying the following mathematical expression:
V₁ x C₁ = V₂ x C₂
⇒ V₂ = V₁ x C₁/C₂
Given:
V₁ = 10 mL
C₁ = 0.65 M
C₂ = 0.055 M
We replace the data in the mathematical expression to calculate V₂:
V₂ = V₁ x C₁/C₂ = 10 ml x (0.65 M)/ (0.055 M) = 118.18 mL ≅ 118 mL
Prehistory is the time before history.
History is usually defined as the time in the past BEFORE written (or similar) solid evidence, for which we can only infer what happened.
So the correct answer is C.
Answer:
Cr₂O₇⁻²(aq) and ClO₃⁻(aq)
Explanation:
At a redox reaction, one substance must be reduced (gain electrons) and others must be oxidized (lose electrons). To evaluate the potential of the substance to be reduced, it's placed a reaction, in standards conditions, with H₂.
The potential reduction is quantified by E°, and as higher is the value of E°, as easy is to the compound to be reduced. So, at a redox reaction, the compound with the greatest E° will be reduced, and the other will be oxidized, in a spontaneous reaction. The values of E° are:
RuO₄⁻(aq) to RuO₄²⁻(aq) E° = + 0.59 V (the reduction reaction is the opposite of the oxidation reaction).
Ni⁺²(aq) E° = -0.257 V
I₂(s) E° = +0.535 V
Cr₂O₇⁻²(aq) E° = +1.33 V
ClO₃⁻(aq) E° = +0.890 V
Pb²⁺(aq) E° = -0.125 V
So, the substances that have E° higher than the E° of the RuO₄⁻²(aq) are Cr₂O₇⁻²(aq) and ClO₃⁻(aq), which are the substances that can oxidize RuO₄⁻(aq) to RuO₄²⁻(aq).