Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

Quantitative chemical analysis. Please show some work, Ill choose best correct a

ID: 872224 • Letter: Q

Question

Quantitative chemical analysis. Please show some work, Ill choose best correct answer asap. Thanks! The quantity of acetylene (HC + CH) in a gas mixture was measured by mass spectrometry, in which the signal for mass number 26 is proportional to the volume percent of acetylene. Subtract the value (0.2 mV) from each measured signal. Prepare a graph to find the volume percent of acetylene in the unknown. Use the method of least squares to find the uncertainties in slope and intercept of your graph and to estimate the uncertainty in the answer to part (a).

Explanation / Answer

Create this table using Excel:

Gas sample

Spike, %

Signal

Sinal -0.2

Signal -0.2-10.6

Blank

0

0.2

0.0

unknown

0

10.8

10.6

0.0

3

0.072

17.1

16.9

6.3

4

0.121

20.2

20.0

9.4

5

0.200

30.0

29.8

19.2

6

0.364

44.6

44.4

33.8

And select the following values for a calibration function:

Spike, %

Signal -0.2-10.6

0

0.0

0.072

6.3

0.121

9.4

0.200

19.2

0.364

33.8

Import these data in Excel and create the graph, I can

Gas sample

Spike, %

Signal

Sinal -0.2

Signal -0.2-10.6

Blank

0

0.2

0.0

unknown

0

10.8

10.6

0.0

3

0.072

17.1

16.9

6.3

4

0.121

20.2

20.0

9.4

5

0.200

30.0

29.8

19.2

6

0.364

44.6

44.4

33.8