The conversion of ammonium cyanide to urea is a second-order reaction. This means that the concentration C of ammonium cyanide at time t is given by 1/C = kt+1/C₀, where C₀ is the initial concentration and k is the rate constant. Assume the initial concentration is known to be 0.1 mol/L exactly. Assume that time can be measured with negligible uncertainty.

a. After 45 minutes, the concentration of ammonium cyanide is measured to be 0.0811 ± 0.0005 mol/L.Estimate the rate constant k, and find the uncertainty in the estimate.

b. Use the result in part (a) to estimate the time when the concentration of ammonium cyanide will be 0.0750 mol/L, and find the uncertainty in this estimate.