CMT400 Assignment 1 (Excel)

Q1. (Sheet 1)Heat capacity is known to be a function of temperature. It is common to express the heat capacity of a gas as the polynomial Cp = a + bT + cT2. The following is a heat capacity data for ammonia gas from 300 K to 750 K. Determine the polynomial constants a, b and c. (Hint: Use Add Trendline)T (K)Cp (J/mol.K)

30035.530

35037.075

40038.619

45040.131

50041.640

55043.131

60044.601

65046.067

70047.510

75048.941

Q2.(Sheet 2)The rate constant for the first order gas phase reaction N2 O5 2NO2 + O2are as follows

T (K)273298308318328338

k ( s-1)0.0787x10-53.46x10-513.5x10-549.8x10-5150x10-5487x10-5

Make the appropriate graph using these data and determine the activation energy, Ea and pre-exponential factor, A.

Q3.(Sheet 3)Consider the following data for the spectrophotometric determination of iron. The measured absorbance A is plotted against the concentration of iron. Determine the concentration of iron in the sample.

Conc (ppm)0.100.2000.5001.000Unknown sample

A0.0810.1710.4320.8570.463

Q4.(Sheet 4)This problem is about calculating the pH of nitrous acid, HNO2 which is a weak acid. You need to solve the following quadratic equation.

where Ka is the acid dissociation constant. X = [H+]C = concentration of the weak acid

i) Find the value for Ka of lactic acid (refer to any general chemistry text book)ii) Find the pH of 0.1 M lactic acid (i.e C =0.1) using the solver method

Q5.(Sheet 5)Plot the following functions:

i) Y = x +5-5