Stoichiometry
In the reaction 2H2+O2 -->2H2 O, what is the mole ratio of H2 to H2O?
1:1
What is the molar mass of water (H2O)?
18 g/mol
Find the percent of composition of carbon in CO2.
27.3%
What is the first step in determining an empirical formula?
Convert the mass of each element to moles.
What is the purpose of balancing chemical equations?
To obey the Law of Conservation of Mass.
If you have 4 moles of NH3 in the reaction N2 + 3H2 --> 2NH3 , how many moles of H2 were required?
6 moles
Calculate the molar mass of calcium nitrate, Ca(NO3)2.
164 g/mol
What is the percent composition by mass of oxygen in a molecule of water (H₂O)?
(Atomic masses: H = 1.01 g/mol, O = 16.00 g/mol)
88.8%
What is the empirical formula of a compound with 40% C, 6.7% H, and 53.3% O?
CH₂O
What type of reaction is: 2HgO--> 2Hg +O2?
Decomposition
If you start with 13.5 grams of aluminum (Al), how many grams of aluminum chloride (AlCl₃) will be produced?
66.7 grams of aluminum chloride
How many moles are in 1.204* 1024 molecules of water?
2 moles
What is the percentage of hydrogen in water (H2O)?
11.1%
The empirical formula is CH, and the molar mass is 78 g/mol. What is the molecular formula?
C₆H₆
Al+O2 --> Al2O3
4Al + 3O2 --> 2Al2O3
How many grams of water are produced from 2 moles of oxygen gas in the reaction 2H2 + O2 --> 2H2O? (Molar mass of water =18 g/mol)
36 grams
What is the mass of .5 moles of CO2?
22 grams
Calculate the percent composition of nitrogen in NH3.
82.4%
A compound contains 52.2% carbon, 13.0% hydrogen, and 34.8% oxygen. What is the empirical formula?
C₂H₆O
What reaction is: AgNO3 + NaCl --> AgCl +NaNO3?
Double replacement
How many grams of aluminum oxide are produced when 54 grams of aluminum reacts with oxygen? 4Al+ 3O2 --> 2Al2O3 (Molar mass of Al = 27 g/mol, Al2O3 = 102 g/mol)
102 grams
If a compound has a formula unit mass of 233.4 g/mol and contains 2 Na, 1 s, and 4 O atoms, what is the compound?
Na2SO4
Determine the percent of sulfur in H2SO4.
32.7%
How do you determine the molecular formula from the empirical formula?
Divide the molar mass by the empirical formula mass and multiply the subscripts.
Balance Fe + H2O --> Fe3O4 + H2