moles —> mass
What is molar mass?
The amount of substance of any sample of a compound
What is a particle?
Ions, atoms, & molecules
Identify the type of reaction: 2H2(g) + O2 --> 2H2O(g) is an example.
Combustion! (redox subtype)
Chemical formulas are the most direct way to represent the ___ ____ of a compound
Elemental makeup
What does an empirical formula show?
The proportions of elements present in a compound, but not the number arrangements of the atoms in the compound
How do you convert mass to moles?
By multiplying the atomic mass number with the given mole number
What is the number of particles in a mole called?
Avogadro’s number
Identify the reaction: 2Na(s) + Cl2(g) --> 2NaCl(s)
Synthesis! (redox subtype)
A 31.25 g sample of a gaseous compound containing only carbon and hydrogen was analyzed to show that it contained 23.44 g of carbon and 7.81 g of hydrogen. What is the percent composition of this compound?
75% Carbon; 25% Hydrogen
What is the empirical formula ratio?
1:2
Convert 15 grams of H2SO4 to moles
0.15 moles
How many atoms are in 1.00 moles of He?
6.02x10^23
Identify the oxidized and reduced species in the following reaction:
3Hg2+ + 2Fe -> 3Hg + 2Fe2+
Hg is reduced, Fe is oxidized
Molar Mass
A compound is composed of 52.14% Carbon, 13.13% Hydrogen, & 34.73% Oxygen by mass. What is the empirical formula?
C2H6O1
How many moles are in 15g of lithium?
2.2 moles of Li
How many atoms are in 1.50 moles of Hg?
9.03x10^23
What are the two general products of an acid/base reaction?
Water and Salt (ionic compound)
What is the molar mass of NaCl?
58.44 g/mol
What are the steps to convert from molecular to empirical formula?
1. Calculate the empirical formula mass
2. Divide the molecular mass by the empirical formula mass?
3. Multiply each subscript in the empirical formula mass
How many atoms are present in 2.5 moles of Silicon?
1.5 x 10^24 atoms
How many moles are in 2.91x10^22 atoms of He?
4.83x10^-2
Determine the products and balance the following reaction:
Na2SO4(aq) + Ba(NO3)2(aq) ->
Na2SO4(aq) + Ba(NO3)2(aq) -> 2NaNO3(aq) + BaSO4(s)
What is the percent composition of sodium bromide?
Na 22.3%; Br 77.7%
1. Change % to grams
2. Convert g—>mol
3. Divide by smallest number of moles
4. Multiply to get a whole number