.produce 340 grams of carbon dioxide ( at STP? C_(3)H_(8)+5O_(2)arrow 3CO_(2)+4H_(2)O

To determine how many grams of propane (C3H8) are needed to produce 340 grams of carbon dioxide (CO2) at standard temperature and pressure (STP), we need to use stoichiometry.<br /><br />First, let's calculate the molar mass of CO2:<br />C: 12.01 g/mol<br />O: 16.00 g/mol<br />Molar mass of CO2 = 12.01 g/mol + (2 × 16.00 g/mol) = 44.01 g/mol<br /><br />Next, we need to find the number of moles of CO2 produced:<br />Number of moles of CO2 = Mass of CO2 / Molar mass of CO2<br />Number of moles of CO2 = 340 g / 44.01 g/mol ≈ 7.75 moles<br /><br />Now, let's look at the balanced chemical equation:<br />C3H8 + 5O2 → 3CO2 + 4H2O<br /><br />From the equation, we can see that 1 mole of propane (C3H8) produces 3 moles of carbon dioxide (CO2). Therefore, we can set up a proportion to find the number of moles of propane needed:<br /><br />1 mole of C3H8 : 3 moles of CO2 = x moles of C3H8 : 7.75 moles of CO2<br /><br />Solving for x, we get:<br />x = (7.75 moles of CO2) / 3 ≈ 2.58 moles of C3H8<br /><br />Finally, let's calculate the molar mass of propane (C3H8):<br />C: 12.01 g/mol<br />H: 1.01 g/mol<br />Molar mass of C3H8 = (3 × 12.01 g/mol) + (8 × 1.01 g/mol) = 44.11 g/mol<br /><br />Now, we can calculate the mass of propane needed:<br />Mass of C3H8 = Number of moles of C3H8 × Molar mass of C3H8<br />Mass of C3H8 = 2.58 moles × 44.11 g/mol ≈ 113.5 grams<br /><br />Therefore, approximately 113.5 grams of propane (C3H8) are needed to produce 340 grams of carbon dioxide (CO2) at standard temperature and pressure (STP).