CHM 120 Lecture Notes - Lecture 18: Molar Mass, Ionic Compound, Formula Unit
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Molar mass- the mass of 1 mol of atoms of an elemtn. Molar mass- the mass of 1 mol of molecules of a molecular compound. Molar mass- the mass of 1 mol of formula units of an ionic compound. 1 ch4 molecule= 1x 12. 02 amu+ 4 x 1. 008 amu= 16. 04 amu (molecular mass) 1 mol ch4 molecules = 1x 12. 01g + 4x 1. 008g= 116. 04g (molar mass) 1nacl formula unit= 1x 22. 99 amu+ 1x 35. 45 amu= 58. 44 amu (formular mass) 1 mol nacl formula units= 1x 22. 99g + 35. 45g = 58. 44g (molar mass) Converting between grams and moles of a compound. Solution map: g compound mol compound (use molar mass compound) Example 1: calculate the number of moles of no2 in 1. 18g of no2. 1mol no2 =1x 14. 01 g+ 2x 16. 00g =46. 01 no2 (molar mass) 1. 18g no2 x 1mol no2/ 46. 01g no2= 0. 0256 mol no2 (3s. f) Converting between grams of a compound and number of molecules.
