What volume of a concentrated HCl solution, which is 36.0% HCl by mass and has a density of 1.179 g/mL, should be used to make 4
1 answer:
Answer:
5.195 ml
Explanation:
Dissociation of HCl yields;
HCl(aq) ⇄ H⁺(aq) + Cl⁻(aq)
∴ [HCl] = [H⁺] = [Cl⁻]
pH = 1.9
= -log[ H⁺]
=
=
= 0.01258 M
Moles of HCl = number of mole × volume
= 0.01258 × 4.80 L
= 0.06042 mole
Mass of HCl = number of moles of HCl × Molar mass of HCl
Mass of HCl = 0.06042 mol × 36.5 g/mol
Mass of HCl = 2.205 grams
Also, given that the density = 1.179 g/mL
Mass of HCl in the solution = 36% of the density
i.e
= 0.4244 grams
Volume of a concentrated HCl solution needed can now be determined as;
=
=
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Answer:
a) 0,014 min⁻¹
b) 1452 seconds.
c) 0,02156 M
d) The faster rate is for the reaction A. The largest rate constant, k, is for A reaction
Explanation:
a) For a first order reaction the half-life is:
<em>(1) </em>As half.life is 49 min. Rate constant -k- is: 0,014 min⁻¹
b) The half-life is defined as the time that takes in descompose the half of the initial concentration of a compound.
As half-life is 726s. In 726s the concentration will be 0,300M, In the next 726s the concentration will be 0,150M. Thus, thae time it takes to decrease concentration until 0,150M is 726s×2= 1452 seconds
c) In the same way, 11072 years are 4 half-life for this reaction, thus:
0,345M/2⁴ = 0,02156 M
d) By definition of half-life, the less half-life, the faster rate. Thus, The faster rate is for the reaction A.
By (1) half-life is inversely proportional to rate constant. Thus, the less half-life, the largest rate constant. The largest rate constant, k, is for A reaction
I hope it helps!