CHEMISTRY 31

Fall, 2014 - Dixon

Homework Set 1 (for Exam 1)

 

Note: Text problems will not be collected but there will be a 10 point quiz on the homework completion date unless otherwise specified

 

Chapter Problems Date to finish

Set 1.1 Sept. 10

Ch. 1 1a, 5, 11, 15, 20, 24, 32

text solutions

Turn in corrected diagnostic quiz by Sept. 10 (10 points).

Additional Problem 1.1 (5 pts total). Phosphoric acid, H3PO4, is available commercially as a mixture that is 85% by weight in water and has a density of 1.70 g/mL. Determine the following quantities:

a) the molarity of H3PO4 in the solution

b) the molarity of water in the solution

c) the volume (in mL) of this acid needed to add to a 100.0 mL volumetric flask to make a 0.100 M solution

solutions

 

Set 1.2 Sept. 24

Ch. 1 35, 37, 42, 46

Ch. 3 1, 2, 5a-d, 11, 14, 16a-f

Ch. 4 4, 9, 11

Additional Problem 1.2 (5 pts total)

A scientist is measuring the sulfate concentration in particulate matter (particles suspended in air). She draws air through a filter at a flow rate of 16.9+0.4 L/min for 248+1 min. The filter is extracted in 5.00+0.02 mL of water. Following analysis of the extract, the sulfate concentration (in the water extract) is found to be 5.7+0.2 mg/mL.

a) Determine the concentration of sulfate in ng/L air

b) Determine the uncertainty in the concentration in (a)

c) List one significant source of uncertainty in the concentration and one insignificant source of uncertainty

(5 pts)

bonus 1 point) Suggest another way in which the scientist could have found the uncertainty in the measurement other than by propagation of uncertainty.

 

Set 1.3 Oct. 6 (no quiz)

Ch. 4 20, 21, 30

Ch. 6 4, 6, 8, 15-17, 19, 21

No Additional Problem