1. Problem In analytical chemistry accuracy describes: (a) How close to each other are data values in the set (b) How wide is data spread (c) The type of precision, that was obtained between different analyst/labs (d) How close to the real value are data values in the set 2. Problem In analytical chemistry reproducibility describes: (a) The type of precision, that was obtained between different analyst/labs (b) The type of precision, that was obtained in a single session analysis by one analyst on the same solutions and equipment (c) How wide is data spread (d) How close to each other are data values in the set 3. Problem Calculate the result and round to appropriate number of significant figures: (0.1062 x 19.25 – 0.0954 × 4.53 0.0918 x 8.79 x 89.80 100.0 100.0
1. Problem
In
(a) How close to each other are data values in the set
(b) How wide is data spread
(c) The type of precision, that was obtained between different analyst/labs
(d) How close to the real value are data values in the set
2. Problem
In analytical chemistry reproducibility describes:
(a) The type of precision, that was obtained between different analyst/labs
(b) The type of precision, that was obtained in a single session analysis by one analyst on
the same solutions and equipment
(c) How wide is data spread
(d) How close to each other are data values in the set
3. Problem
Calculate the result and round to appropriate number of significant figures:
0.1062 × 19.25 − 0.0954 × 4.53
100.0
−
0.0918 × 8.79
100.0
× 89.80
4. Problem
Stock solution with concentration 1 M should be diluted to concentration 0.001 M. Which
of the following procedures gives the smallest final uncertainty of concentration?
(a) One-step dilution of 2.000±0.006 mL stock solution to 2000.0±0.5 mL in volumetric
flask
(b) Two-step dilution: 5±0.01 mL of stock solution to 100±0.08 mL followed by dilution
of 2±0.006 mL of prepaired solution to 100±0.08 mL
(c) Three-step 1:10 dilution: 10±0.02 mL of solution diluted to 100±0.08 mL in volumetric
flask. This operation repeates 3 times
5. Problem
One sample of ore was analyzed by two students. Here are the results of analysys:
21.33, 21.27, 21.27, 21.35, 21.17 (Student 1)
21.00, 21.13, 20.50, 20.98, 20.77 (Student 2)
The real value is 20.88%.
(a) Using Dixon’s Q-test at α = 0.05 determine are there any outliers in both data sets?
(b) What is the 95% confidence intervals for the first student?
(c) What is the 95% confidence intervals for the second student?
(d) Which of them is more accurate?
(e) Which of them is more precise?
6. Problem
To compare two production lots of aspirin tablets, you collect samples from each and analyze
them, obtaining the following results (in mg aspirin/tablet).
232, 274, 255, 235, 257 (Lot 1)
260, 256, 255, 260, 252, 254, 247 (Lot 2)
(a) Compute Fexp value
(b) Is there any evidence at α = 0.05 that there is a significant difference in the variance
between the results for these two samples?
Step by step
Solved in 2 steps with 1 images
