The most common element found in crayons would be carbon and hydrogen. Since crayons are made up of paraffin and other chemical pigments. Paraffin is wax like material, which is derived from petroleum, wood, or coal. All three contain large amounts of hydrocarbons, which is carbon and hydrogen compounds.
Answer:
= 17% (v/v)
Explanation:
% by Volume = (Volume HCl / Volume of Solution)100%
= 15ml/(75ml + 15ml) x 100% = 16.66666667% (calculator answer)
= 17% (v/v) 2 sig figs. based on volume values given.
pH of the buffer solution is 1.76.
Chemical dissociation of formic acid in the water:
HCOOH(aq) ⇄ HCOO⁻(aq) + H⁺(aq)
The solution of formic acid and formate ions is a buffer.
[HCOO⁻] = 0.015 M; equilibrium concentration of formate ions
[HCOOH] + [HCOO⁻] = 1.45 M; sum of concentration of formic acid and formate
[HCOOH] = 1.45 M - 0.015 M
[HCOOH] = 1.435 M; equilibrium concentration of formic acid
pKa = -logKa
pKa = -log 1.8×10⁻⁴ M
pKa = 3.74
Henderson–Hasselbalch equation: pH = pKa + log(cs/ck)
pH = 3.74 + log (0.015 M/1.435 M)
pH = 3.74 - 1.98
pH = 1.76
More about buffer: brainly.com/question/4177791
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