Empirical & Molecular Formula
Emirical formula Haiku
Percentage to mass
Mass to mole, divide by small
Multiply til whole
How do you get from
Mass to Moles
Particles to Moles
Volume of Gas to Moles
1.00 mol/Molar Mass
1mol/6.02x10^23 particles
1mol/22.4L
What is Molar Mass
the mass (in grams) of 1 mole off any substance.
What is Percent Compisition
The percentage by mass of each element in a compound
What is the first thing you do in any mole problem
Where your going on the mole map
What is the molecular formula
Its the same as its experimentally determined by the empirical formula, or it is a simple whole-number multiple of its empirical formula.
How do you get from
Moles to Mass
Moles to Particles
Moles to Volume of Gas
Molar Mass/1.00 mol
6.02x1023 particles/1mol
22.4L/Mol
Find the Molar Mass of H2O
H = (2 x 1.01 g/mol) = 2.02 g/mol
O = (1 x 16.00 g/mol) = 16.00 g/mol
The total Molar Mass = 18.02g/mol
What is the percent composition formula
Percent= Part/Whole x 100%
Dimensional analysis is a versatile and powerful problem-solving technique.
True or False
True
What are the three steps to a molecular formula
1. Determine the empirical Formula
2. Divide the molar mass of the compound by the empirical formula mass
3. Multiply all subscripts in the empirical formula by this number
What volume would 0.600 moles of SO2 gas occupy at STP?
0.600 mol SO2 x 22.4 L/1 mol SO2
= 13.4 L SO2
What is the Molar Mass of Fe2
55.85g + 55.85g
111.7g
What are the 3 step to a percent composition problem
Step 1: Determine the molar mass of the compound.
Step 2: Divide the total mass of each element in the compound by the molar mass calculated in step 1 and multiply each by 100. Round to the nearest 0.01%.
Step 3: Check to see that the %’s add up to 100.
Purpose of Dimensional Analysis
To easily and correctly convert from one unit to another.
Calculate the molecular formula of a compound whose molar mass is 92.0 g/mol and empirical formula is NO2
empirical formula of NO2 = 14.01 + (2 x 16.00). = 46.01 g/mol
92.00g/mol/46.01g/mol
How many molecules of NO2 are in 0.330 moles of NO2?
0.330 mol NO2 x 6.02 x 1023 molecules/1 mol NO2
= 1.99 x 1023 molecules NO2
What is the molar mass PbSO4
(1 x 207.20g) + (1 x 32.07g) + (4 x 16.00g)
=303.27 g/mol
In a typical day, you spend 27% of your time on your phone. How many hours is this?
24 hours x 27/100= 6.48hours
How many minutes are there in two days?
1 day -24 hr
1hr- 60min
2 x 24 x 60/1
=2880 minutes
Determine empirical formula for a compound that is found to contain 40.0% carbon, 6.67% hydrogen, and 53.3% oxygen. The compound’s molar mass is 120.0 g/mol.
Double Jeopardy option 😱😄😁😄👍🏼💵💵💵💵💵💵💵💸💵💸💸💵💸🛢💵💸💸💸💰💰💰💎💎🪙💰
Determine molecular formula for a compound that is found to contain 40.0% carbon, 6.67% hydrogen, and 53.3% oxygen. The compound’s molar mass is 120.0 g/mol.
C 3.33 H 6.60. O3.33
CH2O
Answer to double Jeopardy
Empirical Formula=
of CH2O = 12.01 + (2 x 1.01) + 16.00 = 30.03 g/mol
120.0 g/mol/30.03 g/mol
=4
(CH2O)4 =(C4H8O4)
What is the volume of 7.87 x 1024 molecules of carbon dioxide at STP?
7.87 x 1024 x 1molCo2/6.02 x 1023 x 22.4l/1mol Co2
=(7.87 x 1024 x 1 x 22.4L)/(6.02 x 1023 x 1)293l CO2
What is the Molar mass of AgNo3
(1x107.87g/mol)= 107.87g/mol
(1x14.01g/mol)= 14.01g/mol
(3x16.00g/mol)= 48.00g/mol
169.88
Percent Composition of
silver nitrate, AgNO3
(1x107.87g/mol)= 107.87g/mol
(1x14.01g/mol)= 14.01g/mol
(3x16.00g/mol)= 48.00g/mol
169.88
Ag=(107.87/169.88) x 100= 63.50%
N=(14.01/169.88) x 100=8.25%
O=(48.00/169.88) x 100=28.25%
How many days is 5000 minutes?
60min-1hr
24hr- 1 day
3.5 days
500/1 x 1 /60 x 1 /24 = 3.4722
always round up to a whole