Answer:
pH = 6.80. The aqueous solution is slightly acid
If pH is 7.00 at 37°C, solution is neutral
Explanation:
2H₂O ⇄ H₃O⁺ + OH⁻ Kw = 2.4×10⁻¹⁴
To determine the pH of a solution, we must consider the [H₃O⁺]
[H₃O⁺] . [OH⁻] = 2.4×10⁻¹⁴
[H₃O⁺] = [OH⁻] → √2.4×10⁻¹⁴ = [H₃O⁺]
1.55×10⁻⁷ = [H₃O⁺]
pH = - log 1.55×10⁻⁷ = 6.80
pH = 7 → neutral
pH < 7 → acid
pH > 7→ basic
1) chromium(III) nitrate is acidic, because it is the salt of weak base (chromium(III) hydroxide Cr(OH)₃) and strong acid (nitric acid HNO₃).
2) sodium hydrosulfide is basic, because it is the salt of strong base (sodium hydroxide MaOH) and weak acid (hydrogen sulfide H₂S).
3) zinc acetate is little basic, because zinc hydroxide (Zn(OH)₂) is stronger base than acetic acid (CH₃COOH).
You are given
the hydrate CoCl2.6H20. You are required to get the percentage of water in this
chemical substance. The first thing to do is to get the molar mass of CoCl2.6H20
and CoCl2. The molar masses are 237.8 grams per mole and 129.8 grams per mole
respectively. The formula in getting the percentage of water is
%=[1-(grams
of CoCl2/grams of CoCl2.6H20)]*100.
Substitute the
molar masses of CoCl2.6H20 and CoCl2.
%=[1-(129.8 grams
of CoCl2/237.8 grams of CoCl2.6H20)]*100.
<u>% of water
= 45.42%</u>
