Post on 18-Jan-2016
Chapter 7Chemical Quantities
The MoleThe Mole
SI base unit to measure the amount of a substance
1 mole of anything = 6.022 x 1023
representative particles
2. How many molecules are in 2.12 mole of propane(C3H8)?
3. How many moles are there in 3.01 x 1023 forumla units of NaOH?
Ex. molecular formula of H2O
H = 2(1.01) = 2.02 O = 1(16.0) =16.0 18.02 gGram formula mass – mass of one
mole of an ionic compound formula mass of CaCl2
9.45 mole N2O3 76.0 g N2O3
1 mole N2O3
= 718 g N2O3
Find the number of moles in 92.2 g of iron(III) oxide.
22.4 L = 1 mole
22.4 L = 6.022 x 1023 representative particles
Density of a gas is in units of g/L g 22.4 L
Percent Composition
Shows the simplest whole-number ratio of the atoms in a compound
Can be the true formula sometimes
1.Analysis shows a compound to contain 26.56% K, 35.41% Cr, 38.03% O. Find the empirical formula.
Indicates the ratio of the atoms
Shows the actual number of atoms Can be reduced sometimes