What mass of propane (C3H8) is needed to produce 346g carbon dioxide in the following reaction?

C3H8(g)+5O2(g)---> 3CO2(g) +4H2O(g)

A. 115g C3H8
B. 1.86g C3H8
C. 5075g C3H8
D. 346g C3H8

mols CO2 needed = grams/molar mass = approx 7.9 but I've estimated. You need to do it more accurately as well as all of the numbers that follow.

Using the coefficients in the balanced equation, convert mols CO2 to mols C3H8. That's 7.9 mols CO2 x (1 mol C3H8/3 mols CO2) = 7.9 x (1/3) = about 2.5
Now convert mols C3H8 to grams. That's grams = mols x molar mass = ?

To determine the mass of propane (C3H8) needed to produce 346g of carbon dioxide (CO2), you need to use stoichiometry. Stoichiometry is a method used in chemistry to calculate the quantities of reactants and products involved in a chemical reaction.

First, let's determine the molar mass of propane (C3H8):
C3H8 = (3 x atomic mass of Carbon) + (8 x atomic mass of Hydrogen)
= (3 x 12.01 g/mol) + (8 x 1.01 g/mol)
= 36.03 g/mol + 8.08 g/mol
= 44.11 g/mol

Next, let's use the balanced equation to convert the mass of carbon dioxide produced to the mass of propane needed. The balanced equation shows a 3:1 ratio between carbon dioxide and propane.

From the balanced equation, we know that 3 moles of CO2 are produced for every 1 mole of C3H8 used.

To convert the grams of CO2 to moles of CO2, divide the given mass (346g) by the molar mass of CO2:
Moles of CO2 = Mass of CO2 / Molar mass of CO2
Moles of CO2 = 346g / 44.01 g/mol
Moles of CO2 ≈ 7.85 moles

Now, using the stoichiometric ratio, we can determine the moles of C3H8 required:
Moles of C3H8 = Moles of CO2 / Stoichiometric ratio
Moles of C3H8 = 7.85 moles / 3
Moles of C3H8 ≈ 2.62 moles

Finally, convert moles of C3H8 to grams of C3H8 using the molar mass of C3H8:
Mass of C3H8 = Moles of C3H8 x Molar mass of C3H8
Mass of C3H8 = 2.62 moles x 44.11 g/mol
Mass of C3H8 ≈ 115.47g

Therefore, the mass of propane needed to produce 346g of carbon dioxide is approximately 115g. Hence, the correct answer is option A.