Conversions
When doing mass conversions, what do you need to know about the compound/element?
Molar Mass
What is Avogadro's Number?
6.022 * 1023
What is the constant to convert moles to liters?
22.4 L
What is percent composition useful for?
Determining the chemical formula
H2O2 is an example of which type of formula?
Molecular
What is the molar mass of HCl?
36.46 g/mol
How many moles are in 7.07*1023 atoms of nitrogen?
1.17 moles
What are the units used for volume
L for Liters
A 13.60 g sample of a compound, containing only magnesium and oxygen, is decomposed. There was 5.40 g of oxygen obtained during the decomposition. What is the percent composition of this compound?
39.7% O
60.3% Mg
What is the empirical for C6H12O6?
CH2O
What is the mass of 2.56 moles of sodium hydroxide?
102 g
How many atoms are in 1.5 moles of silver?
9.0*1023 atoms
What is STP and why is it important?
standard temp and pressure. 0 degrees celsius and 1 atm. This lets us know that we do not need to account for pressure and temp in our equation
What is the percent composition of Na2S2O3?
% Na = 29.1%
% S = 40.6%
% O = 30.4%
Determine the empirical formula for a compound with the following percent composition:
15.8% carbon and 84.2% sulfur
CS2
How many moles are in 75.4 g of H2SO4?
0.769 moles
How many moles are in 3.0*1025 representative particles of sugar?
50 moles
At STP, what is the volume of 0.58 moles of HCl gas?
13 L
What is the mass of chlorine and hydrogen in 56 g of HCl? The percent composition is 2.8% H and 97.2% Cl
1.6 g H
54.4 g Cl
Determine the empirical formula for a compound with the following percent composition:
67.9% C, 5.70% H, 26.4% N
C3H3N
How many moles are in 92.1 g of hydrogen phosphate?
1.12 moles
How many representative particles of salt are in 9.89 moles?
5.96*1024 representative particles
At STP, how many moles are in 110.2 L of bromine gas?
4.92 moles
A 3.56 g sample of pure iron powder was heated in gaseous chlorine, and 10.39 g of an iron chloride was formed. What is the percent composition of this compound?
34.3% Fe
65.7% Cl
A major textile dye manufacturer developed a new yellow dye. The dye has a percent composition of 75.95% C, 17.72% N, and 6.33% H by mass with a molar mass of about 240 g/mol. Determine the molecular formula of the dye.
C15H15N3