Moles-Molecules-Atoms
Calculate the molar mass of CH3COOH.
60.052 g/mol
What is the conversion factor for grams to moles?
grams x 1 mol/grams = moles
d = m/v
How do you find the percent by mass of an element?
% mass of element = mass of element(g)/mass of compound(g) x 100%
How are empirical formulas different from molecular formulas?
The empirical formula gives the lowest whole number ratio of the atoms or moles of the elements in a compound.
What is the molar mass of Cl?
70.906 g/mol (diatomic)
How many grams are in 1.56 moles of Glycerol (C3H8O3)?
143.67g C3H8O3
How many gas particles occupy a volume of 22.4L?
6.022 x 1023 particles
What is the percent of Mg in Mg(OH)2?
41.7%
Find the empirical formula of a compound that contains: 92.31% C and 7.69% H.
CH
How many moles are in 3.87 x 1024 atoms of copper?
6.43 mol Cu
Write the conversion factor for grams to atoms.
grams x 1 mol/molar mass(g) x 6.022x1023 atoms/1 mol = atoms
Determine the volume of 0.5 mol of N2 @ STP.
11.2L N2 @ STP
What is the percent composition of Na3PO4?
Na = 42.1%
P = 18.9%
O = 39%
What is the empirical formula for a compound that has: 40% C, 6.67% H, and 53.3% O?
CH2O
How many atoms are in 2.73 moles of sodium phosphate?
1.32 x 1025 atoms Na3PO4
Calculate the number of grams in 2.3 x 1024 atoms of silver.
411.98g Ag
What is the mass of 122.4L of Ne @ STP?
110.27g Ne @ STP
Find the percent of Iron in 25g of Fe3O4.
72.36% Fe
Find the empirical formula for a compound with 5.91g Mg and 17.18g Cl.
MgCl2
What is the difference between a molecule and a formula unit?
molecule - covalent, formula unit - ionic
(example go to L.23 in class #6)
How many atoms are in 15g of methane (CH4)?
2.82 x 1024 atoms CH4
What is the molar mass of a compound with a density of 1.964 g/L @ STP?
43.99 g/mol @STP
What is the percent composition of a compound that contains 2.7369g of Cl, 0.4116g of O, and 0.7971g of P?
Cl = 69.36%, O = 10.43%, P = 20.21%
Calculate the molecular formula for the compound: 12.2g N and 27.8g O. (MW = 92 g/mol)
N2O4