1) C6H12O6 + 6O2 --> 6CO2 + 6H2O
How many molecules of CO2 are formed if 5 grams of C6H12O6 react with oxygen?
Step 1) Change the 5 grams of C6H12O6
into mole. Divide by the fomula mass.
=> the formula mass of C6H12O6 = 6
X 12 + 12 X 1 + 6 x 16 = 180
=> mole of C6H12O6 = 5/180 = 0.028 mole
Step 2) The stoichiometric ratio is finish / start.
=> ratio = 6/1
Step 3) The mole of CO2 = (6 /1) X 0.028 = 0.168
Step 4) The number of molecules CO2 is 6 X 1023
X 0.168 = 1.01 X 1023
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2) C3H8 + 5O2 --> 3CO2 + 4H2O
If 72 grams of water are formed how many grams propane(C3H8) is burnt in oxygen?
Step 1) Change the 72 grams of H2O into mole. Divide
by the fomula mass.
=> the formula mass of H2O = = 18
=> mole of H2O = 72/18 = 4 mole
Step 2) The stoichiometric ratio is finish / start.
=> ratio = 1/4
Step 3) The mole of C3H8=
(1/4) X 4 = 1
Step 4) The mass of one mole of C3H8
= 1 X formula mass = 44 grams
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| Stoichiometry more mixed exercises * HINT Ratio = Finish / Start
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1) C6H12O6 + 6O2 --> 6CO2 + 6H2O How many molecules of CO2 are formed if 5 grams of C6H12O6 react with oxygen?
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Solution |
2) C3H8 + 5O2 --> 3CO2 + 4H2O If 72 grams of water are formed how many grams propane(C3H8) is burnt in oxygen? |
Solution |
3) H2O2 --> O2 + H2 If 3.1 X 1023 molecules of H2O2 react what mass of oxygen gas is formed? |
No
solution is offered for this. Check with your teacher |
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4) H2SO3 + 2H2S --> 3H2O + 3S If 3.1 X 1024 molecules of H2SO3 react what mass of sulfur is formed? |
No
solution is offered for this. |