a) First, to get ΔG°rxn we have to use this formula when:
ΔG° = - RT ㏑ K
when ΔG° is Gibbs free energy
and R is the constant = 8.314 J/mol K
and T is the temperature in Kelvin = 25 °C+ 273 = 298 K
and when K = 4.4 x 10^-2
so, by substitution:
ΔG°= - 8.314 * 298 *㏑(4.4 x 10^-2)
= -7739 J = -7.7 KJ
b) then, to get E° cell for a redox reaction we have to use this formula:
ΔE° Cell = (RT / nF) ㏑K
when R is a constant = 8.314 J/molK
and T is the temperature in Kelvin = 25°C + 273 = 298 K
and n = no.of moles of e- from the balanced redox reaction= 3
and F is Faraday constant = 96485 C/mol
and K = 4.4 x 10^-2
so, by substitution:
∴ ΔE° cell = (8.314 * 298 / 3* 96485) *㏑(4.4 x 10^-2)
= - 2.7 x 10^-2 V
For this question, we apply the Raoult's Law. The formula is written below:
P = P*x
where
P is the partial pressure
P* is the vapor pressure of the pure solvent
x is the mole fraction
The partial pressure is solved as follows:
P = Total P*x = (250 torr)(0.857) = 214.25 torr
Hence,
214.25 = (361 torr)(x)
<em>x = 0.593 or 59.3%</em>
The molarity of the HCl solution : 1.052 M
<h3>Further e
xplanation</h3>
Given
Volume of HCl = 38.55 ml
mass of Na₂CO₃ (MW=106 g/mol)=2.15 g
Reaction
Na₂CO₃(aq) + 2HCl (aq)→ 2NaCl (aq) + CO₂ (g) + H₂0 (l)
Required
The molarity of the HCl solution
Solution
mol Na₂CO₃ :
From the equation, mol ratio Na₂CO₃ : HCl = 1 : 2, so mol HCl :
The molarity :
When solid melts, the temperature of the substances increases and the substance absorbs heat energy, converting the solid to a liquid.
