Chapter 3 HW.pdf - Homework#2 Chapter 3 Stoichiometry 23...

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1 Homework #2 Chapter 3 Stoichiometry 23. Need to find average molar mass of X (M X ) ࠵? ࠵? = (࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵? ࠵? 46 ) (࠵? ࠵? 46 ) + (࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵? ࠵? 47 ) (࠵? ࠵? 47 ) + (࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵? ࠵? 48 ) (࠵? ࠵? 48 ) + (࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵? ࠵? 49 ) (࠵? ࠵? 49 ) + (࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵? ࠵? 50 ) (࠵? ࠵? 50 ) ࠵? ࠵? = (0.0800)(45.95269 ࠵?࠵?࠵?) + (0.0730)(46.951764 ࠵?࠵?࠵?) + (0.7380)(47.947947 ࠵?࠵?࠵?) + (0.0550)(48.94784 ࠵?࠵?࠵?) + (0.0540)(49.944792 ࠵?࠵?࠵?) = 47.88 ࠵?࠵?࠵? Find the atomic weight on the periodic table that matches 47.88 amu. Ti titanium 26. Need to find the mass present of 151 Eu and 153 Eu Know M Eu = 151.96 amu fraction of 151 Eu = x ࠵? ࠵?࠵? 151 = 150.9196 ࠵?࠵?࠵? fraction of 153 Eu = 1-x ࠵? ࠵?࠵? 153 = 152.9209 ࠵?࠵?࠵? ࠵? ࠵?࠵? = (࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵? ࠵?࠵? 151 ) (࠵? ࠵?࠵? 151 ) + (࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵? ࠵?࠵? 153 ) (࠵? ࠵?࠵? 153 ) 151.96 ࠵?࠵?࠵? = ࠵?(150.9196 ࠵?࠵?࠵?) + (1 − ࠵?)(152.9209 ࠵?࠵?࠵?) −0.96 ࠵?࠵?࠵? = (−2.001 ࠵?࠵?࠵?)࠵? ࠵? = 0.48 Therefore 48% 151 Eu and 52% 153 Eu 27. Need to find the molar mass of 185 Ru (࠵? ࠵?࠵? 185 ) ࠵? ࠵?࠵? = (࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵? ࠵?࠵? 187 ) (࠵? ࠵?࠵? 187 ) + (࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵? ࠵?࠵? 185 ) (࠵? ࠵?࠵? 185 ) 186.207 ࠵?࠵?࠵? = (0.6260)(186.956 ࠵?࠵?࠵?) + (1 − 0.6260)࠵? ࠵?࠵? 185 ࠵? ࠵?࠵? 185 = 185.0 ࠵?࠵?࠵? 28. Need to find the average molar mass of X (M X ) ࠵? ࠵? = (࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵? ࠵? ࠵? ) (࠵? ࠵? ࠵? ) + (࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵? ࠵? ࠵? ) (࠵? ࠵? ࠵? ) + (࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵? ࠵? ࠵? ) (࠵? ࠵? ࠵? ) + (࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵? ࠵? ࠵? ) (࠵? ࠵? ࠵? ) ࠵? ࠵? = (0.0140)(203.973 ࠵?࠵?࠵?) + (0.2410)(205.9745 ࠵?࠵?࠵?) + (0.2210)(206.9759 ࠵?࠵?࠵?) + (0.5240)(207.9766 ࠵?࠵?࠵?) = 207.22 ࠵?࠵?࠵? Find the atomic weight on the periodic table that matches 207.22 amu. Lead (Pb)
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2 34. Note: Grey information is given a) Moles of Sample 4.24 ࠵? ࠵? 6 ࠵? 6 ( 1 ࠵?࠵?࠵? ࠵? 6 ࠵? 6 78.12 ࠵? ࠵? 6 ࠵? 6 ) = 0.0543 ࠵?࠵?࠵? ࠵? 6 ࠵? 6 Molecules in Sample 0.0543 ࠵?࠵?࠵? ࠵? 6 ࠵? 6 ( 6.02214×10 23 ࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵? 6 ࠵? 6 1 ࠵?࠵?࠵? ࠵? 6 ࠵? 6 ) = 3.27 × 10 22 ࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵? 6 ࠵? 6 Atoms in Sample 3.27 × 10 22 ࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵? 6 ࠵? 6 ( 12 ࠵?࠵?࠵?࠵?࠵? 1 ࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵? 6 ࠵? 6 ) = 3.92 × 10 23 ࠵?࠵?࠵?࠵?࠵? b) Mass of Sample 0.224 ࠵?࠵?࠵? ࠵? 2 ࠵? ( 18.02 ࠵? ࠵? 2 ࠵? 1 ࠵?࠵?࠵? ࠵? 2 ࠵? ) = 4.04 ࠵? ࠵? 2 ࠵? Molecules in Sample 0.224 ࠵?࠵?࠵? ࠵? 2 ࠵? ( 6.02214×10 23 ࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵? 2 ࠵? 1 ࠵?࠵?࠵? ࠵? 2 ࠵? ) = 1.35 × 10 23 ࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵? 2 ࠵? Total Atoms in Sample 1.35 × 10 23 ࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵? 2 ࠵? ( 3 ࠵?࠵?࠵?࠵?࠵? 1 ࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵? 2 ࠵? ) = 4.04 × 10 23 ࠵?࠵?࠵?࠵?࠵? c) Moles of Sample 2.71 × 10 22 ࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵?࠵? ࠵?࠵?
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