Review Sheet

Unit 4 review sheet The following are examples of objectives and problems that you should have mastered. They will be on your test tomorrow. Objectives are in bold. 1) Calculate the molar mass of any given compound. (example problems on pg 238239 ) You should be able to do this easily 2) Use molar mass to convert between mass in grams and amount in moles of a chemical compound and number of molecules. (example problems on pg 240-42) Problem A) Find the mass in grams of 4 moles of Ba(NO3)2.

Problem B) Find the number of moles of ethanol (C2H5OH) in 207 grams of ethanol.

3) Calculate the percent composition of a given chemical compound. Problem C) Find the percent composition of fructose (C6H12O6)

4) Determine an empirical formula from either a percentage or a mass composition. (example problems on pg 246 and 247 ) Problem D) Quantitative analysis shows that a compound contains: 13.04% H, 52.17% C, and 34.78 % O Find the empirical formula.

Problem E) Analysis of a 50.0 g sample of a compound known to contain only carbon, hydrogen, and oxygen indicates a carbon content of 19.4 g and a hydrogen content of 4.84 g. What is the empirical formula of this compound?

5) Determine a molecular formula from an empirical formula. (example on pg2489) In problem E, the empirical formula of a compound of hydrogen, carbon, oxygen was found to be CH3O. Experimentation shows that the molar mass of this compound is 62.3 g/mol. What is the compound’s molecular formula?