G Currell & A A Dowman, Wiley-Blackwell, 2009

The pH of a solution is related to the hydrogen ion concentration, [H ^{+}] mol L^{-1}(or mol dm^{-3}), by the equation:

pH = -log([H^{+}])

Calculate (to 3 significant figures) the hydrogen ion concentration, [H^{+}], for a solution with pH = 8.3.- 2.49 × 10
^{-4}mol L^{-1}(or mol dm^{-3}) - 5.01 × 10
^{-9}mol L^{-1}(or mol dm^{-3}) - 2.00 × 10
^{8}mol L^{-1}(or mol dm^{-3}) - 2.00 × 10
^{-8}mol L^{-1}(or mol dm^{-3})

- 2.49 × 10
The method reproducibility, given by the percentage coefficient of variation, CV(%), achievable for an analysis of a solution of fractional concentration, *C*, has been estimated as:

CV(%) = 2^{{1 - 0.5 log(C)}}

Estimate the coefficient of variation (to 2 significant figures) that should be achievable when measuring a concentration of 10ppm.- 1.0%
- 4.5%
- 11%
- None of the above

The difference in loudness, *L*_{1}-*L*_{2}, in decibels between two sounds with power densities,*P*_{1}and*P*_{2}in Wm^{-2}is given by the equation:

*L*_{1}-*L*_{2}= 10log(*P*_{1}/*P*_{2})

The loudness of sound from a loudspeaker is 80.0 dB, when the volume is increased by*doubling*the power density output. Calculate (to 3 significant figures) the new loudness in dB.- 81.3 dB
- 100 dB
- 160 dB
- 83.0 dB

The voltage, *V*, on a specific capacitor at a time,_{t}*t*, is given by the equation:

*V*= 60 × {1 - exp(-_{t}*t*/ 0.5)}

Which of the following statements is NOT correct?- The voltage,
*V*, decreases with time,_{t}*t*. - At time,
*t*= 0, the voltage,*V*= 0 volts_{t} - After a long time, when
*t*>> 0.5, the voltage,*V*≈ 60 volts_{t} - The voltage,
*V*= 30 volts when_{t}*t*= 0.347 (3 sf)

- The voltage,
Calculate the value of the rate constant,

*k*, in the Arrhenius equation:given that:

*E*= 80 kJ mol_{a}^{-1 - }Activation energy of the reaction*T*= 400 K - Temperature*R*= 8.314 J K^{-1}mol^{-1}- Gas constant*A*= 6.2 × 10^{8}s^{-1 }- Constant for this reaction- 6.05 × 10
^{8}s^{-1} - 0.0221 s
^{-1} - 1.79 × 10
^{19}s^{-1} - None of the above

- 6.05 × 10