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Percent Composition of Compounds
Atomic Masses and Moles
Limiting Reactants
Determining Formula of a Compound
Balancing Chemical Equations
100
Assume one mole of H2O MM H20: appr. 18 What is the mass percent of H?
11.11%
100
How many moles are in 25 grams of water?
1.39 moles
100
4Al2O3 + 9Fe ----> 3Fe3O4 + 8Al If 25.4 g of Al2O3 is reacted with 10.2 g of Fe, determine the limiting reagent.
Fe
100
A chemist finds that an unknown compound contains 50.5% S and 49.95 % O by weight. Calculate its empirical formula
SO2
100
CO2+ H2O --> C6H12O6 +O2 Balance the formula of photosynthesis
6CO2 + 6H2O --> C6H12O6 + 6O2
200
One mole of NaCl is dissolved in two moles of H20. what is the mass percent of Chlorine in the solution?
36.95%
200
How many grams are in 4.5 moles of Li2O?
134.1 grams
200
C3H8 + O2 ----> CO2 + H2O Balance the reaction. If you start with 14.8 g of C3H8 and 3.44 g of O2, determine the limiting reagent
O2
200
A certain compound containing only phosphorus and oxygen is 56.3 % P (by mass) Determine the empirical formula of this compound.
P2O3
200
At 1000ºC, ammonia gas, NH3(g), reacts with oxygen gas to form gaseous nitric oxide, NO(g), and water vapor. Balance this reaction
4 NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)
300
Find the mass percent of the elements present in H2S04
H:2.06% S:32.6% 0:65.3%
300
how many molecules are in 23 moles of oxygen gas?
1.38*10^25 molecules of O2
300
Al2(SO3)3 + 6 NaOH ----> 3 Na2SO3 + 2 Al(OH)3 Determine the number of grams of excess reagent left over in the reaction.
1.84 grams NaOH
300
Propanol contains 60.0% carbon, 13.4% hydrogen, and 26.6% oxygen. Determine the empirical formula of propanol.
C3H80
300
Al + KOH + H2SO4 + H2O ----> KAl(SO4)2 · 12H2O + H Balance.
2Al + 2KOH + 4H2SO4 + 22 H2O ----> 2KAl(SO4)2 · 12H2O + 3 H2
400
Calculate the mass percent of the elements in glucose C6H12O6.
C:40.0% H:6.67% 0:53.3%
400
how many molecules are in 25 grams of NH3?
8.85*10^23 molecules
400
If a sample containing 18.1 g of NH3 is reacted with 90.4 g of CuO, which is the limiting reactant ? How many grams of N2 will be formed?
10.6 grams
400
A certain hydrocarbon compound containing only C and H is 83.6% C and 16.4% H by mass. The experimentally determined molecular mass is 86.2 amu. What is the chemical formula for this hydrocarbon?
C6H14
400
C4H10S + O2 ---> CO2 + H2O + SO2 Balance.
2C4H10S + 15O2 ---> 8CO2 + 10H2O + 2SO2
500
The "Golden Rain"(KNO3) precipitate is formed by mixing 2KI and Pb(NO3)2 to form PbI2 and 2KNO3. What is the mass percent of oxygen in comparison to all the reactants?
17.9%
500
How many grams are in 8.2*10^22 molecules of N2I6?
106.7 grams
500
Silver nitrate, AgNO3, reacts with ferric chloride, FeCl3, to give silver chloride, AgCl, and ferric nitrate, Fe(NO3)3. A solution containing 25.0 g of AgNO3 is mixed with another solution containing 45.0 grams of FeCl3. What is the maximum number of moles of AgCl that could be obtained from this mixture?
0.147 mol
500
A 5.438 gram sample, was found to contain 2.549 grams of iron, 1.947 grams of oxygen, and 0.9424 grams of phosphorus. What is its empirical formula?
Fe3O8P2
500
C5H7O + O2 ---> CO2 + H2O Balance.
4C5H7O + 25O2 ---> 20CO2 + 14H2O