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How many grams of oxygen react with 72.0 grams of C5H12 by using this equation-C5H12+8O2 and 5CO2+6H2O?
A chemist requires 0.423 mol Na2CO3 for a reaction. How many grams does this correspond to?
The test tube should be held vertically with the opening pointing straight up to avoid spills when heating contents. true or false?
Methanol (CH3OH) is produced commercially by the catalyzed reaction of carbon monoxide and hydrogen:
CO(g)+2H2(g)←−→CH3OH(g).
An equilibrium mixture in a 2.00 −L vessel is found to contain 4.33×10−2 mol CH3OH, 0.180 mol CO, and 0.303 mol H2 at 500 K.
Calculate Kc at this temperature.
CO(g)+2H2(g)←−→CH3OH(g).
An equilibrium mixture in a 2.00 −L vessel is found to contain 4.33×10−2 mol CH3OH, 0.180 mol CO, and 0.303 mol H2 at 500 K.
Calculate Kc at this temperature.
6 soil grab samples were collected from a contaminated site. Analytical results are presented in Table. Based on the results indicate how many grab samples needed to retrieve from site if statistical goal is to obtain RSD 2% to be associated with data?
Grab Sample 1
Analytes Arsenic Concentration (mg/kg) 3.79
Analytes Manganese Conc 9.32
Analytes Cobalt Conc 5.21
Analytes Lead Cone 10
Grab Sample 2
Analytes Arsenic Conc 1.24
Analytes Manganese Conc 0.95
Analytes Cobalt Conc 2.22
Analytes Lead Conc 6
Grab Sample 3
Analytes Arsenic Conc 2.26
Analytes Manganese Conc 6.34
Analytes Cobalt Conc 8.87
Analytes Lead Conc 12
Grab Sample 4
Analytes Arsenic Conc 1.55
Analytes Manganese Conc 4.32
Analytes Cobalt Conc 6.72
Analytes Lead Conc 11
Grab Sample 5
Analytes Arsenic Conc 3.99
Analytes Manganese Conc 7.32
Analytes Cobalt Conc 6.21
Analytes Lead Conc 9
Grab Sample 6
Analytes Arsenic Conc 6.89
Analytes Manganese Conc 8.87
Analytes Cobalt Conc 5.21
Analytes Lead Conc 10
Grab Sample 1
Analytes Arsenic Concentration (mg/kg) 3.79
Analytes Manganese Conc 9.32
Analytes Cobalt Conc 5.21
Analytes Lead Cone 10
Grab Sample 2
Analytes Arsenic Conc 1.24
Analytes Manganese Conc 0.95
Analytes Cobalt Conc 2.22
Analytes Lead Conc 6
Grab Sample 3
Analytes Arsenic Conc 2.26
Analytes Manganese Conc 6.34
Analytes Cobalt Conc 8.87
Analytes Lead Conc 12
Grab Sample 4
Analytes Arsenic Conc 1.55
Analytes Manganese Conc 4.32
Analytes Cobalt Conc 6.72
Analytes Lead Conc 11
Grab Sample 5
Analytes Arsenic Conc 3.99
Analytes Manganese Conc 7.32
Analytes Cobalt Conc 6.21
Analytes Lead Conc 9
Grab Sample 6
Analytes Arsenic Conc 6.89
Analytes Manganese Conc 8.87
Analytes Cobalt Conc 5.21
Analytes Lead Conc 10
In a study of the poisoning of fish, 0.500 g of samples of fish tissue were analysed for barium. Each sample was digested with a permanganate-sulfuric acid mixture, and the volume adjusted to 10 mL and to construct calibration curve, 0.500-g samples of uncontaminated fish tissue were injected with various amounts of Ba+2, as follows:
Standard 0: 0.00µg Ba+2
Standard 1: 50 µg Ba+2
Standard 2: 100 µg Ba+2
Standard 3: 150 µg Ba+2
The absorbance values are indicated below:
Standard Number 0; Absorbance 0.015
Standard Number 1; Absorbance 0.220
Standard Number 2; Absorbance 0.415
Standard Number 3; Absorbance 0.602
If all samples and standards were treated in identical manner, what was the concentration of barium (in µg Ba per g of fish) in a fish sample whose absorbance value was 0.421 and 0.378, respectively?
Standard 0: 0.00µg Ba+2
Standard 1: 50 µg Ba+2
Standard 2: 100 µg Ba+2
Standard 3: 150 µg Ba+2
The absorbance values are indicated below:
Standard Number 0; Absorbance 0.015
Standard Number 1; Absorbance 0.220
Standard Number 2; Absorbance 0.415
Standard Number 3; Absorbance 0.602
If all samples and standards were treated in identical manner, what was the concentration of barium (in µg Ba per g of fish) in a fish sample whose absorbance value was 0.421 and 0.378, respectively?
In a study of the poisoning of fish, 0.500 g of samples of fish tissue were analysed for barium. Each sample was digested with a permanganate-sulfuric acid mixture, and the volume adjusted to 10 mL and to construct calibration curve, 0.500-g samples of uncontaminated fish tissue were injected with various amounts of Ba+2, as follows:
Standard 0: 0.00µg Ba+2
Standard 1: 50 µg Ba+2
Standard 2: 100 µg Ba+2
Standard 3: 150 µg Ba+2
The absorbance values are indicated below:
Standard Number: 0; Absorbance 0.015
Standard Number: 1; Absorbance 0.220
Standard Number: 2; Absorbance 0.415
Standard Number: 3; Absorbance 0.602
Standard 0: 0.00µg Ba+2
Standard 1: 50 µg Ba+2
Standard 2: 100 µg Ba+2
Standard 3: 150 µg Ba+2
The absorbance values are indicated below:
Standard Number: 0; Absorbance 0.015
Standard Number: 1; Absorbance 0.220
Standard Number: 2; Absorbance 0.415
Standard Number: 3; Absorbance 0.602
For the following analytical scenario below which involved initially diluting 20 ml of the original water sample into a 1000 ml volumetric flask. Subsequently, the sample was prepared and analyzed as depicted below:
Volumetric Flask (500 ml) #1
Sample Composition: 5 ml of sample + 0 mL of 300 ppm Na 0.5% LiCl2
Absorbance: 0.12
Volumetric Flask (500 ml) #2
Sample Composition: 5 ml of sample + 1 ml of 300 ppm Na + 0.5% LiCl2
Absorbance: 0.17
Volumetric Flask (500 ml) #3
Sample Composition: 5 ml sample + 2 ml of 300 ppm Na + 0.5% LiCl2
Absorbance: 0.21
I. If all the flasks were diluted to a final volume of 500 ml with distilled water calculate the final
concentration of sodium in the sample through a graphical and mathematical solution. (10 pts)
II. Why Lanthanum and Cesium or Lithium are added to solutions to be analysed for Calcium and
Sodium respectively? (6pts)
Volumetric Flask (500 ml) #1
Sample Composition: 5 ml of sample + 0 mL of 300 ppm Na 0.5% LiCl2
Absorbance: 0.12
Volumetric Flask (500 ml) #2
Sample Composition: 5 ml of sample + 1 ml of 300 ppm Na + 0.5% LiCl2
Absorbance: 0.17
Volumetric Flask (500 ml) #3
Sample Composition: 5 ml sample + 2 ml of 300 ppm Na + 0.5% LiCl2
Absorbance: 0.21
I. If all the flasks were diluted to a final volume of 500 ml with distilled water calculate the final
concentration of sodium in the sample through a graphical and mathematical solution. (10 pts)
II. Why Lanthanum and Cesium or Lithium are added to solutions to be analysed for Calcium and
Sodium respectively? (6pts)
A student obtained the following results for the normality of a Nitric acid solution: 0.424; 0.528; 0.621; 0.433; 0.537.
Should 0.621 as a result be rejected statistically?
Should 0.621 as a result be rejected statistically?
Show work and indicate in which of the following measurements has the detection limit been reached? (12 pts)
Measurements | Analyte Signal | Blank Signal
SAMPLE 1 | 1.434 ± 0.12 | 01.26 ± 0.09
SAMPLE 2 | 2.32 ± 0.09 | 0.33 ± 0.14
SAMPLE 3 | 0.85 ± 0.39 | 0.97 ± 0.24
Measurements | Analyte Signal | Blank Signal
SAMPLE 1 | 1.434 ± 0.12 | 01.26 ± 0.09
SAMPLE 2 | 2.32 ± 0.09 | 0.33 ± 0.14
SAMPLE 3 | 0.85 ± 0.39 | 0.97 ± 0.24
