Chapter 36 Multiple choice questions

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. Derive the units for the extinction coefficient ε from the Beer-Lambert law, which states:
$A=\epsilon c\mathcal{l}$
where A is the absorbance (no units), c is the concentration (in mol m^-3), and   is the thickness of the absorbing material (in m).

m mol^-1 correct incorrect

m³ mol^-1 correct incorrect

mol m^-2 correct incorrect

m² mol^-1 correct incorrect

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. Derive the units for frequency ν given that:
$c=\nu \lambda$
where c = 3 x 10⁸ ms^-1 and λ is the wavelength (in m).

s correct incorrect

s^-1 correct incorrect

m^-1s correct incorrect

s^-2 correct incorrect

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. Given that a has units of J mol^-1, b has units of J, c has units of K, d has units of J K^-1 mol^-1, e has units of mol, and f has units of J K^-1 mol^-1, select the equation from the list below that is not dimensionally correct.

$c=\frac{a}{f}$ correct incorrect

d = f correct incorrect

b = ae + dce correct incorrect

d = ac correct incorrect

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. We need to do an experiment to determine the emf (in V) of a solution at different concentrations (in mol dm^-3). We know the data follow the following equation:
$\Delta emf+2k\log c-\frac{2k\text{A}\sqrt{c}}{1+\sqrt{c}}=2kBc+E_{\text{const}}$,
where A and B are constants (with unspecified units) and
$k=\frac{(\ln 10)RT}{F}$.
(R = 8.314 J K^-1 mol^-1, F = 96485 C mol^-1, and T = 298 K).
Derive the units of the $\frac{2k\text{A}\sqrt{c}}{1+\sqrt{c}}$ term?

J C^-1 mol dm^-3 correct incorrect

V correct incorrect

V^-1 mol dm^-3 correct incorrect

J C^-1 mol^0.5 dm^-1.5 correct incorrect

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. What are the dimensions of the following term: $\ln \left(\frac{T_2}{T_1}\right)$.

K^-1 correct incorrect

K correct incorrect

0 correct incorrect

1 correct incorrect

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. Derive the SI unit for the Faraday constant F, given that:
$\Delta S=nF\left(\frac{\text{d}emf}{\text{d}T}\right)$.

${\text{J V mol}}^{-1}$ correct incorrect

$\text{A}\text{s}{\text{mol}}^{-1}$ correct incorrect

$\text{A}{\text{s}}^{-1}{\text{mol}}^{-1}$ correct incorrect

${\text{V J}}^{-1}{\text{ mol}}^{-1}$ correct incorrect

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. We must look at an IR spectrum which measures $\overline{\nu }$ in cm^-1. How would we convert the frequency to m^-1?

Multiply by 10 correct incorrect

Divide by 10 correct incorrect

Multiply by 100 correct incorrect

Divide by 100 correct incorrect

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. How should we convert mol dm^-3 to mol m^-3?

Divide by 1000 correct incorrect

Multiply by 1000 correct incorrect

Divide by 100 correct incorrect

Multiply by 100 correct incorrect

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. Manipulate the following data so that it is dimensionless:
Molar conductivity Λ = 0.15 S m² mol^-1.

$\frac{\Lambda }{{\text{S m}}^{\text{2}}{\text{mol}}^{–}{}^{\text{1}}}=0.\text{15}$ correct incorrect

$\frac{\Lambda }{{\text{S m}}^{\text{2}}}=0.{\text{15 mol}}^{–}{}^{\text{1}}$ correct incorrect

$\Lambda =0.\text{15}$ correct incorrect

$\frac{\Lambda }{\text{S }}=0.\text{15}$ correct incorrect

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. Manipulate the following data so that it is dimensionless:
$emf=\left(132\times {10}^{-3}\right)\text{V}$.

$\frac{emf}{\text{V}}=132$ correct incorrect

$\frac{emf}{{10}^3\text{V}}=132$ correct incorrect

$\frac{emf}{{10}^{-3}\text{V}}=132\times {10}^{-3}$ correct incorrect

$\frac{{10}^{3}emf}{\text{V}}=132$ correct incorrect