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Unformatted text preview: 1 Mass to Moles to Mass A Ca(NO 3 ) 2 sample contains 2.04 grams of nitrogen. How much does the Ca(NO 3 ) 2 sample weigh? Mass to Moles to Mass – Section A.8 2.04 g N x ? = _____ g Ca(NO 3 ) 2 grams N moles N moles Ca(NO 3 ) 2 grams Ca(NO 3 ) 2 (ratio) (ratio) (ratio) Correct # of parts X somethings 1 something = Y Parts Value given Ratio in Formula (true statement = 1) Value asked for x Ratios of “1” for Ca(NO 3 ) 2 1 mol Ca 1 mol Ca(NO 3 ) 2 2 mol N 1 mol Ca(NO 3 ) 2 6 mol O 1 mol Ca(NO 3 ) 2 1 mol Ca 2 mol N 1 mol Ca 6 mol O 2 mol N 6 mol O 164.086 g Ca(NO 3 ) 2 1 mol Ca(NO 3 ) 2 Ratios from Chemical Formula: Ca(NO 3 ) 2 Ratios from Periodic Table 40.078 g Ca 1 mol Ca 14.007 g N 1 mol N 15.999 g O 1 mol O Mass to Moles to Mass Mass to Moles to Mass – Section A.8 A Ca(NO 3 ) 2 sample contains 2.04 grams of nitrogen. How much does the Ca(NO 3 ) 2 sample weigh? Mass to Moles to Mass Mass to Moles to Mass – Section A.8 grams N moles N moles Ca(NO 3 ) 2 grams Ca(NO 3 ) 2 (ratio) (ratio) (ratio) 2.04 g N 1 mol N 14.007 g N * 1 mol Ca(NO 3 ) 2 2 mol N * 164.086 g Ca(NO 3 ) 2 1 mol Ca(NO 3 ) 2 * = 11.9 g Ca(NO 3 ) 2 A Ca(NO 3 ) 2 sample contains 14.03 grams of oxygen. How many grams of N does it contain? 1. 4.68 g N 2. 4.09 g N 3. 12.27 g N 4. 2.05 g N grams O moles O moles N grams N (ratio) (ratio) (ratio) Mass to Moles to Mass Mass to Moles to Mass – Section D.3 Ratios also work with reaction coefficients: 4Fe(s) + 3Cl 2 (g) 2Fe 2 Cl 3 (s) How many grams of Fe are needed to react with 75.0 grams of chlorine gas (Cl 2 )? grams Cl 2 moles Cl 2 moles Fe grams Fe (ratio) (ratio) (ratio) 75.0 g Cl 2 1 mol Cl 2 70.90 g Cl 2 * 4 mol Fe 3 mol Cl 2 * = 78.8 g Fe 55.85 g Fe 1 mol Fe * 4Fe(s) + 3Cl 2 (g) 2Fe 2 Cl 3 (s) 75.0 g Cl 2 x 1 mol Cl 2 / 70.90g 1.058 mol Cl 2 x 4 mol Fe / 3 mol Cl 2 1.410 mol Fe x 55.85 g Fe/1 mol Fe 78.8 g Fe How many grams of Fe 2 Cl 3 can be produced with 53.1 grams of chlorine gas (Cl 2 ) and an excess of Fe? (MW Fe 2 Cl 3 = 218.1 g/mol) Enter question text...Enter question text....
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This note was uploaded on 03/30/2010 for the course CH 101 taught by Professor Bigham during the Fall '08 term at N.C. State.
 Fall '08
 BIGHAM
 Mole

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