Chemistry Test 2 - Summer 2008, Exams of Chemistry

Download Chemistry Test 2 - Summer 2008 and more Exams Chemistry in PDF only on Docsity! CHM 1045 Summer, 2008 Test 2 Name (print)___________________ Show your work for complete (and partial) credit. Report your answers to the correct number of significant figures, and use units where appropriate. All chemical equations should balance; indicate phases. NA=6.022x1023 1. What is the mass, in grams, of one average water molecule (H2O)? 2. The analysis of an organic compound showed that it contained 0.175 mol of C, 0.140 mol of H, and 0.0350 mol of N. Its molecular mass is about 160. How many atoms of carbon are there in the empirical formula for the compound and how many in the molecular formula? 3. Predict the products of the following reaction. Balance the equation. ___Ca(OH)2(aq) + ___HCl(aq) → Write the net ionic equation for the following two molecular equations. 4. Mg(s) + 2HNO3(aq) → Mg(NO3)2(aq) + H2(g) 5. NH3(aq) + HCl(aq)→ NH4Cl(aq) 6. Aqueous solutions of silver (I) nitrate and potassium sulfate were mixed. Solid silver (I) sulfate formed, leaving potassium nitrate in solution. What is the net ionic equation for the reaction? The following information applies to the next four problems. Compound: MgCl2 Mg(NO3)2 AgCl AgNO3 f.w.(g/mol): 95.211 148.435 143.321 169.87 MgCl2(aq) + 2AgNO3(aq) → 2AgCl(s) + Mg(NO3)2(aq) 7. How much does 0.055mol of magnesium chloride weigh? 8. What mass of MgCl2 is required to form 1.223g of AgCl? 9. What mass of AgNO3(aq) is contained in 555mL of 0.0477M AgNO3(aq)? 10. What volume of 0.250M AgNO3(aq) is required to react with 32.3mL of 0.250M MgCl2(aq)? 11. In the titration of a 25.00mL sample of 0.1875M HCl, what volume of 0.1444M NaOH titrant will be required to reach the endpoint? 12. The amount of calcium in a 15.0-g sample was determined by converting the calcium to calcium oxalate, CaC2O4. The CaC2O4 weighed 12.8 g. What is the percent of calcium in the original sample? 13. How many grams of hydrogen are present in 17.9 g of water?