Question 2.Order the following elements from most to least reactive.*
1 answer:
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Answer:
Partial pressure of in the gas was 733 torr and mass of
in the sample was 2.12 g.
Explanation:
a) Total pressure of gas = (partial pressure of water vapour)+(partial pressure of )
Here partial pressure of water vapour is 21 torr and total pressure of gas is 754 torr.
So, partial pressure of = (total pressure of gas)-(partial pressure of water vapour) = (754 torr) - (21 torr) = 733 torr
b) Lets assume that behaves ideally. Hence-
PV=nRT
where P is pressure of , V is volume of
, n is number of moles of
, R is gas constant and T is temperature in kelvin
here P = 733 torr = = 0.9646 atm
V = 0.65 L, R = 0.082 L.atm/(mol.K), T=(273+22)K = 295 K
So,
=
= 0.0259 moles
As 3 moles of are produced from 2 moles of
therefore 0.0259 moles of
are produced from
moles or 0.0173 moles of
.
Molar mass of = 122.55 g
So mass of in sample =
= 2.12 g
Answer:
pH = 12.7
Explanation:
First, we have to calculate the [Ca²⁺] in a solution of about 250 ppm CaCO₃.
Now, let's consider the dissolution of Ca(OH)₂ in water.
Ca(OH)₂(s) ⇄ Ca²⁺(aq) + 2 OH⁻(aq)
The solubility product Ksp is:
Ksp = [Ca²⁺] × [OH⁻]²
[OH⁻] = √(Ksp/[Ca²⁺]) = √(6.5 × 10⁻⁶/2.5 × 10⁻³) = 5.1 × 10⁻² M
Finally, we can calculate pOH and pH.
pOH = -log [OH⁻] = -log (5.1 × 10⁻²) = 1.3
pH + pOH = 14 ⇒ pH = 14 - pOH = 14 - 1.3 = 12.7