Which of the following has the greatest mass? 1.0 mol zinc 1.0 mol copper 1.0 mol potassium 1.0 mol sulfur all have the same mass

How many mol of CO2 are in 3.3 g of carbon dioxide? (a) 145.233 mol (b) 0.075 mol (c) 150 mol (d) 13 mol (e) none of the above

How many mol of CO2 are in 3.3 g of carbon dioxide? MOLE (mol)‏ Mass (g)‏ Particles (atoms, fu or mc’s)‏ Molar AVOGADRO’S NUMBER ( )‏ 1 mol CO2 3.3 g CO2 = 0.075 mol CO2 44.01 g CO2 How many mol of CO2 are in 3.3 g of carbon dioxide?

How many grams of uranium are in 5.00 X 1022 atoms of pure uranium? (a) 19.8 g (b) 0.0830 g (c) 0.000349 g (d) 1.19 x 1025 g (e) none of the above

( )‏ ( )‏ = 19.8 g U Molar AVOGADRO’S NUMBER 1 mol U 238.00g U MOLE (mol)‏ Mass (g)‏ Molar AVOGADRO’S NUMBER Particles (atoms, fu or mc’s)‏ ( )‏ ( )‏ 1 mol U 238.00g U 5.00 x 10 22 atoms U 6.022 x 1023 atoms U 1 mol U = 19.8 g U How many grams of uranium are in 5.00 X 1022 atoms of pure uranium?

Find n = molar mass = 192.92g/mol In order to determine the molecular formula of a compound you only need to know its empirical formula? True False ??? HF5 H2F10 Find n = molar mass = 192.92g/mol empirical mass 95.96 g/mol n = 2

To find molecular formula… A. Find empirical formula. B. Find empirical mass C. Find n = molar mass empirical mass D. Multiply all parts of empirical formula by n

A compound having an approximate molar mass of 165-170g/mol has the following percent composition by mass. Determine its molecular formula. 42.87% C 3.598% H 28.55 % O 25.00% N C2H2ON C4H4O2N2 C6H6O3N3 CHON none of the above

C6H6O3N3 n = molar mass empirical mass = 167g mol = 2.98 56.05 g/mol Step 1) %  g Step 2) g  mol Step 3) mol mol Step 4) return to whole 42.87% C 3.598% H 28.55% O 42.87g C 3.598g H 28.55g O = 2 C X = 3.57 mol C / 1.78 mol = 3.56 mol H = 2 H C2H2ON = 1.78 mol O = 1 O 25.00% N 25.00g N = 1.78 mol N / 1.78 mol = 1 N n = molar mass empirical mass = 167g mol = 2.98 56.05 g/mol C6H6O3N3

Determine the percent composition of sulfuric acid. a) 28.57% H, 14.29 % S, 57.14% O b) 2.055% H, 32.70 % S, 65.25% O c) 1.02% H, 32.70 % S, 16.31% O d) none of the above

Determine the percent composition of sulfuric acid. MOLAR MASS of H2SO4 = 98.09 g/mol % H = mass H = 2.02 g . = 0.02055 molar mass 98.09 g % S = mass S = 32.07 g . = 0.3270 molar mass 98.09 g % H = mass O = 64.00 g . = 0.6525 molar mass 98.09 g 2.055% H, 32.70 % S, 65.25% O

Percent Abundance Practice – Part I Silicon has three naturally ocurring stable isotopes, silicon-28, silicon-29 and silicon-30 with respective percent abundances of 92.23%, 4.69% and 3.08%. What is the average atomic mass of silcon? Weighted Average = Value A (%A) + Value B (% B) + Value C (% C) + … 28amu (.9223) + 29amu (.0469) + 30 amu (.0308) = 28.11 amu