posted by reis on .
Liquid carbon disulﬁde reacts with 415 mL of
oxygen to produce the gases carbon dioxide
and sulfur dioxide. What volume of carbon
dioxide is produced?
Answer in units of L
This is a "simple" stoichiometry problem. Here is the format for solving all of these.
1. Write and balance the equation.
CS2 + 3O2 ==> CO2 + 2SO2
2. Convert what you have (in this case mL O2) to mols. The problem doesn't say it is a standard conditions but it must be. mols O2 = L/22.4 = about 0.0185
3. Using the coefficients in the balanced equation, convert mols O2 to mols of what you want (in this case CO2). That is done this way.
0.0185 mols O2 x (1 mol CO2/3 mols O2) = about 0.0062
4. Now convert mols CO2 to volume in L.
0.0062 mols CO2 x 22.4L/mol = about 0.14 L.
This 4-step procedure will do them all; print this out for future reference.
NOTE: Sometimes grams is given in the problem and not L. If that is done then mols = grams/molar mass
Sometimes the product is wanted in grams and not volume; in that case grams = mols x molar mass.