WHAT IS PH????
1 answer:
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Answer:
(a) Cu²⁺ +2e⁻ ⇌ Cu
(c) 0.07 V
Explanation:
(a) Cu half-reaction
Cu²⁺ + 2e⁻ ⇌ Cu
(c) Cell voltage
The standard reduction potentials for the half-reactions are+
<u> E°/V </u>
Cu²⁺ + 2e⁻ ⇌ Cu; 0.34
Hg₂Cl₂ + 2e⁻ ⇌ 2Hg + 2Cl⁻; 0.241
The equation for the cell reaction is
E°/V
Cu²⁺(0.1 mol·L⁻¹) + 2e⁻ ⇌ Cu; 0.34
<u>2Hg + 2Cl⁻ ⇌ Hg₂Cl₂ + 2e⁻; </u> <u>-0.241 </u>
Cu²⁺(0.1 mol·L⁻¹) + 2Hg + 2Cl⁻ ⇌ Cu + Hg₂Cl₂; 0.10
The concentration is not 1 mol·L⁻¹, so we must use the Nernst equation
(ii) Calculations:
T = 25 + 273.15 = 298.15 K
The units are nm (nano-meter), km (kilo-meter), pm (pico-meter), dm (decimeter), mm (millimeter), m (meter), cm (centimeter), hm (hectometer) and gm (gigameter). Now we can express each of these units in terms of m.
1 nm = , 1 Km =
1 pm =
, 1 dm = 0.1 m, 1 mm = 0.001 m, 1 cm = 0.01 m, 1 hm = 100 m, 1 gm =
. Thus the decreasing unit will be
gm>km>hm>m>dm>cm>mm>nm>pm
Explanation:
Using Beer-Lambert's law :
Formula used :
where,
A = absorbance of solution
c = concentration of solution
l = length of the cell
= molar absorptivity of this solution
According to question:
A = (C) : absorbance measured by the spectrometer
c = (B) : concentration, in mol/L, of the stock solution from which the sample was made
l = (A): pathlength of light through the cell
ε = (D) : molar absorptivity, a constant unique to that substance at that wavelength