Assuming that you weighted a piece of silver five times and each time you got 52 grams. However, the actual weight from the Bureau of Standards said it should weigh 50 g. (a) What is the % relative errors? (b) What type of error does this exemplify? (c) Does this affect (a) reliability (b) Accuracy (c) both a & b

Assuming that you weighted a piece of silver five times and each time you got 52 grams. However, the actual weight from the Bureau of Standards said it should weigh 50 g. (a) What is the % relative errors? (b) What type of error does this exemplify? (c) Does this affect (a) reliability (b) Accuracy (c) both a & b

Introductory Chemistry: An Active Learning Approach

6th Edition

ISBN:9781305079250

Author:Mark S. Cracolice, Ed Peters

Publisher:Mark S. Cracolice, Ed Peters

Chapter3: Measurement And Chemical Calculations

Section: Chapter Questions

Problem 128E: In Active Example 3-29 you calculated that you would have to work six weeks to earn enough money to...

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In Active Example 3-29 you calculated that you would have to work six weeks to earn enough money to buy a 1082.49 television. You would be working five shifts of four hours each at 9.25/hr. But, alas, when you received your first pay check, you found that exactly 23 of your earnings had been withheld for social security, federal and state income taxes, and workers compensation insurance. Taking these into account, how many weeks will it take to earn the 1082.49?
2. Quantitative analysis student Analytical analyzed an ore sample for its lead content and obtained a mean of 4.75% Pb for five measurements. If the certified true value is 4.50%, what is the (a) percent error? (b) percent accuracy?
5-8. A method of analysis yields masses of gold that are low by 0.4 mg. Calculate the percent relative error caused by this result if the mass of gold in the sample is *(a) 500 mg. *(c) 150 mg. (b) 250 mg. (d) 70 mg.
How many of the following should be included in a good hypothesis? (i) A prediction of the results of the experiment (ii) A step-by-step walkthrough of how to do the experiment with specific references to amounts of reactants, glassware used, and other experimental details (iii) A summation of the data collected after doing the experiment, with comments on accuracy and precision if possible. (iv) A detailed list of chemicals that will be used (v) Waste disposal procedures (vi) A brief scientific explanation of the predicted results. Said another way, the hypothesis should include a scientific explanation of why the predicted results are expected. 1 2 3 4 5
The points on the bullseye are measurements whose exact value is the center of the bullseye. Indicate the correct statement: (A). The points of target 3 have clearly less standard deviation than that of target 2. (B). Target 2 points have the worst repeatability of all. (C). The points of target 3 are a set of measurements that lead to a fairly accurate value of the variable, but the instrument cannot be considered very precise. (D). Target 4 points only have systematic errors.
How many of the following should be included in a good hypothesis? (1) A prediction of the results of the experiment (ii) A step-by-step walkthrough of how to do the experiment with specific references to amounts of reactants, glassware used, and other experimental details (iii) A summation of the data collected after doing the experiment, with comments on accuracy and precision if possible. (iv) A detailed list of chemicals that will be used (vi) A brief scientific explanation of the predicted results. Said another way, the hypothesis should include a scientific explanation of why the predicted results are expected. (v) Waste disposal procedures 0 1 O 2 O 3 0 4 0 5
2) As an example of precision and accuracy of data, suppose the % carbon in a single compound has been measured thrce separate times by 2 different students. The theoretical % carbon is 21.34%. Student 1: trial 1:26.11%, trial 2: 26.24% trial 3: 25.92 %, Avg - 26.09 Student 2: trial 1: 20.35%. trial 2: 22.64 % trial 3: 19.79 %. Avg = 20.93 a) Which student had the more precise data and how can you tell? b) Which student had the more accurate data and how can you tell? 3a) Calculate the % error of Student 1 data in problem 2 above. Show all work below. WATCH SIG FIGS
7. 22 This question is about several salts. (a) A hydrated salt, compound A, is analysed and has the following percentage composition by mass: Cr, 19.51%; CI, 39.96%; H, 4.51%; O, 36.02%. Calculate the formula of compound A, showing clearly the water of crystallisation. Show your working. formula of compound A = (b) A student carries out an experiment to determine the amount of water of crystallisation in the formula of another hydrated salt. The student intends to remove the water by heating the hydrated salt. A diagram of the apparatus used by the student is shown below. crucible pipeclay triangie The student adds the hydrated salt to the crucible and weighs the crucible and contents. The student heats the crucible and contents and allows them to cool. The student weighs the crucible and residue. The student's results are shown below. 16,84 Mass of crucible + hydrated salt/g 16.26 Mass of crucible + residue after heating/g
The hydrogen ion concentration of a sample of each substance is given. Calculate the pH of the substance. (Round your answers to one decimal place.) (a) Oranges: [H+] = 2.5 × 10-4 M (b) Apples: [H*] = 1.3 × 10 M %D (c) Hominy (lye): [H*] = 3.9 × 10-13 Need Help? Read It Watch It DETAILS SPRECALC7 4.7.003.MI. 0/6 Submissions Used MY NOTES ASK YOUR TEAC The pH reading of a sample of each substance is given. Calculate the hydrogen ion concentration of the substance. (Give your answers in scientific notation, correct to one decimal place.) (a) Vinegar: pH = 3 [H+] = 10 M (b) Milk: pH 6.5 %D [H*] = 10 M Need Help? Read It Watch It Master It
(a) (b) 3. For each image below, record the volume with the correct significant figures. a. beaker b. volumetric flask C. buret d. volumetric pipet e. graduated cylinder -50 ml ±5% (c) M (d) (e) 50 ml 50 ml 40 30 -20 No. 1000 10 24 50 mL 25 50 mL 45 40 30 25 20 mL 10
Veylinder (mL) Deylinder (g/mL) error Method Mass (g) Veylinder Digital Calipers Water mm3 mL Displacement 4. Explain why 1 cm 10 mm, but 1 cm 1000 mm'. You can use words and/or equations/math in your explanation! (2 pts) is more prerise?ow de 5. Base or yr ur d ita, whia mothud Joi kn w. - pis) gul Callpers or water displaceime.
The standard solution is prepared by dissolving a known mass of zinc pellets with conc. HCl. The solution is then neutralized, transferred into a 250 mL volumetric flask and filled to the calibration mark. If 0.9809 g of Zn was weighed using an electronic balance with a relative uncertainty of ± 0.01 % and the 250 mL volumetric flask has a known relative uncertainty of ± 0.06 %, what would be the absolute uncertainty of the concentration of the solution? The molecular weight of the zinc pellets is 65.39 g/mol