CHEMPH108 Week 1 Quiz 1

CHEMPH108 Week 1 Quiz 1 | Mohawk College

Module 1 - Assignment

Question 1

For the following data set, calculate the %RSD to the correct number of sig. digits. Assume no data are rejected.

·         10.025

·         10.025

·         10.115

·         10.251

·         10.215

·         10.151

·         10.115  

·         0.086  

·         11.228  

·         0.85

Question 2

A series of measurement were made and the following were found:

average =12.5%

standard deviation=0.4%

n=5 data points

The 99.5% confidence interval is...

Pick the best answer..  

·         12.5±1.0 %  

·         12.5±0.7 %  

·         12.54±0.1 %  

·         12.5±0.5 %

Question 3

Check the following set of data for any outliers:

8.75, 8.51, 8.25, 8.61, 8.85, 9.95

Which of the following statements is correct?  

·         Qcalc = 0.65

·         Data point 9.95 can be rejected  

·         Qcalc = 0.15

·         Data point 8.25 cannot be rejected  

·         Qcalc = 0.65

·         Data point 9.95 cannot be rejected  

·         Qcalc = 0.15

·         Data point 8.25 can be rejected

Question 4

Given the following set of data calculate the average to the correct number significant digits:

·         7.11

·         10.11

·         7.12

·         7.10

·         7.13

·         7.13  

·         7.6  

·         7.12  

·         7.118  

·         7.166  

·         7.62

Question 5

Given the following set of data calculate the standard deviation to the correct number significant digits:

·         12.12

·         10.12

·         10.11

·         10.09

·         10.09

·         10.08  

·         0.83  

·         0.0164  

·         0.02 

·         0.825

Question 6

For a given analysis: ff the true value =2.63, the experimental mean=3.53, the standard deviation is 0.19 and the number of measurements is 3, then what is the tcalc value is?

Report your answer to 2 decimal places.

Question 7

An analysis was run a known iron sample of 8.32% Fe.  The following results were obtained by an analyst: 8.75, 8.51, 8.25, 8.61

Which of the following statements is true assuming none of the data points are outliers?  

·         Tcalc = 1.99

·         The analysis is not accurate at the 95% confidence interval.  

·         Tcalc = 17.05

·         The analysis is not accurate at the 95% confidence interval.  

·         Tcalc = 1.99

·         The analysis is accurate at the 95% confidence interval.  

·         Not enough information is given to calculate Tcalc.

Question 8

One type of analysis was carried out n1=3 times and the second type of analysis required n2=5 repeats. Calculate the pooled degrees of freedom.

Question 9

Calculate the Spooled value for the following data measured from two different experimental methods:

Data Set 1                            Data Set 2

%                            %

9.14                        9.31

9.08                        9.81

9.04                        9.78

9.10                        9.18

9.19                        9.81

Assume there are no outlying data points.

·         Spooled =0.22  

·         Spooled =0.04  

·         Spooled =8.000

Question 10

Given the following results:

Method 1: mean= 25.55% Ca,  n=6

Method 2:  mean = 27.02% Ca, n=5

·         If spooled = 0.85, which of the following statements is true?  

·         Tcalc = 2.86

·         The 2 methods are not producing statistically different results at the 95% confidence level.  

·         Tcalc=10.38

·         The 2 methods are not producing statistically different results at the 95% confidence level  

·         Tcalc = 2.86

·         The 2 methods are producing statistically different results at the 95% confidence level.

Question 11

A calibration curve was plotted of Absorbance as function of Concentration of ASA in units of ppm and the best fit through the line was found to be A=0.001 x ASAconc.

A 12.13 mL aliquot of the original unknown ASA solution was diluted to a total volume of 245.1 mL.

If the diluted unknown ASA had an absorbance of 0.263, what was the concentration of the original ASA in the unknown in units of ppm? Report your answer to 2 places after the decimal point. No marks for units.

5,314.2 margin of error +/- 1%

Question 12

Calculate the equation of the best line through the following data set:

X             y

0.00        2.92

2.00        3.44

4.00        5.44

6.00        7.34

8.00        10.64

10.00     11.32

Do not force the equation through 0,0.