Wilfrid Laurier University X C O www.saplinglearning.ca/i 2/17/2017 55 PM A 81.8

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Wilfrid Laurier University X C O www.saplinglearning.ca/i 2/17/2017 55 PM A 81.8/100 2/17/2017 12:45 PM Gradebook Attempts Score Print Calculator Periodic Table Question 8 of 11 Map Sapling Learning A 0.3110 g rock sample of unknown concentration was dissolved in HCl and diluted to 100.0 mL. Aliquots of 20.00 mL of this unknown solution were added to different volumes of a 2.08 ugMmL Ca standard solution and diluted to 200.0 mL. Find the weight percent of Ca in the rock sample and the associated uncertainty from the x-intercept using the method of least squares Emission Intensity Unknown (mL) Standard (mL) Final Volume (mL) 20.00 0.00 200.0 212.0 2000 500 200 3980 20.00 10.00 200.0 622.0 20.00 20.00 200.0 1000.0 Weight Percent Uncertainty Number Number Ca ools O Previous 3 Give Up & View Solution Check Answer Next Exit Ask me anything A OAssignment Information Available From /3/2017 06:0C 2/17/2017 11:5 Due Date: Points Possible: 100 Grade Category: Default Description: Policies Homework You can check your answers. You can view solutions when you c up on any question You can keep trying to answer each you get it right or give up. You lose 5% of the points available in your question for each incorrect O eTextbook o Help With This Topic OWeb Help & Videos O Technical Support and Bug Repo 1.25 PM ENG 2017-02.

Explanation / Answer

Molarity of rock sample (M1) = (Weight of rock sample/Molecular weight of rock sample)*(1000/100)

= (0.3110/W)*(1000/100)

= 3.11/W

Molarity of Ca (M2) = (Weight of Ca/Molecular weight of Ca)*(1000/200)

= (2.08*10-6/40)*(1000/200)

= 0.26*10-6

M1V1 = M2V2

V1 = Initial volume

V2 = Final Volume

3.11*20/W = (0.26*10-6)(200+20)

MW = (3.11*20)/(0.26*10-6)*220

= 1.08*106 grams

Molarity of rock sample = 3.11/1.08*106

= 2.86*10-6

Final Concentration = (M1.M2)/(M1V1 + M2V2)

= (0.26*10-6*2.86*10-6)/((0.26*10-6*20)+(2.1*10-5* 200)

= X

Weight Percent of solution = X*100

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