Carbon dioxide is released into the air from the combustion of octane (C8H18). How much octane will you need to get 5.00 moles of carbon dioxide? What is the mass of the octane?
well.... ive got reallly no clue, so anything u say wld help!
All of these stoichiometry problems are pretty much standard.
Step 1. Write the balanced chemical equation.
2C8H18 + 25 O2 ==> 16CO2 + 18H2O
Step 2. We want 5.00 mols CO2. Convert that to mols C8H18 using the balanced equation.
mols C8H18 = mols CO2 x (2 mols C8H18/16 mols CO2)= xx.
(Note how the unit we don't want cancels --in this case we want mols CO2 to cancel and it does-- and the one we want to keep does not cancel--in this case we want mols C8H18 to remain and it does.) The xx is the answer to the first part of the question.
Step 3. Now we convert mols octane to grams octane remembering that grams = mols x molar mass.
mols octane (from step 2) x molar mass octane = yy grams octane.
Check my work.
Post your work if you get stuck.
71.25
When copper(II) oxide is heated in the presence of hydrogen gas, elemental copper and water are produced. What mass of copper can be obtained if 33.8 g copper(II) oxide is used?
To determine the amount of octane needed to produce 5.00 moles of carbon dioxide, we start by examining the balanced chemical equation for the combustion of octane:
2 C8H18 + 25 O2 → 16 CO2 + 18 H2O
From the equation, we see that 2 moles of octane produce 16 moles of carbon dioxide. Therefore, we can set up a proportion to calculate the amount of octane needed:
2 moles of octane / 16 moles of carbon dioxide = x moles of octane / 5.00 moles of carbon dioxide
By cross-multiplying and solving for x, we can find the amount of octane needed:
x = (2 moles of octane / 16 moles of carbon dioxide) * 5.00 moles of carbon dioxide
x = 0.625 moles of octane
So, to obtain 5.00 moles of carbon dioxide, you will need 0.625 moles of octane.
To find the mass of the octane, we can use its molar mass. The molar mass of octane (C8H18) can be calculated by summing the atomic masses of all its constituents:
Molar mass of octane = (8 * molar mass of carbon) + (18 * molar mass of hydrogen)
Molar mass of octane = (8 * 12.01 g/mol) + (18 * 1.01 g/mol)
Molar mass of octane ≈ 114.22 g/mol
Since the ratio of moles to mass is 1:1, the mass of 0.625 moles of octane can be calculated as:
Mass of octane = 0.625 moles of octane * 114.22 g/mol
Mass of octane ≈ 71.38 g
Therefore, you will need approximately 0.625 moles of octane to produce 5.00 moles of carbon dioxide, and the mass of the octane required is approximately 71.38 g.