What mass of H2O would be produced during a combustion analysis of .43213 g of ephedrine?
Write and balance the equation, then refer to the link below to the general procedure of working a stoichiometry problem.
http://www.jiskha.com/science/chemistry/stoichiometry.html
To determine the mass of H2O produced during the combustion analysis of ephedrine, we first need to understand the chemical reaction involved.
The chemical formula of ephedrine is C10H15NO. In a combustion analysis, a substance reacts with oxygen to produce carbon dioxide (CO2) and water (H2O). The balanced chemical equation for the combustion of ephedrine is:
C10H15NO + aO2 → bCO2 + cH2O
To determine the values of a, b, and c, we need to balance the equation. The number of carbon, hydrogen, and oxygen atoms must be the same on both sides of the equation.
The molecular formula of ephedrine contains 10 carbon (C) atoms, 15 hydrogen (H) atoms, and one nitrogen (N) atom. Adding up the individual atoms gives us:
C: 10 × 1 = 10
H: 15 × 1 = 15
N: 1 × 1 = 1
O: 0 × 16 = 0
To balance the equation, we need to add coefficients to the reactants and products. Balancing the carbon (C) atoms first, we have:
C10H15NO + aO2 → 10CO2 + cH2O
Now, let's balance the hydrogen (H) atoms:
C10H15NO + aO2 → 10CO2 + 15H2O
Lastly, we balance the oxygen (O) atoms:
C10H15NO + 23O2 → 10CO2 + 15H2O
From the balanced equation, we can see that the molar ratio between ephedrine and water is 1:15. This means that for every mole of ephedrine burned, 15 moles of water are produced.
To determine the mass of H2O produced, we need to calculate the number of moles of ephedrine in .43213 g. To do this, we divide the mass of ephedrine by its molar mass.
The molar mass of ephedrine (C10H15NO) is calculated by adding the atomic masses of the individual elements:
C: 10 × 12.01 g/mol = 120.1 g/mol
H: 15 × 1.008 g/mol = 15.12 g/mol
N: 1 × 14.01 g/mol = 14.01 g/mol
O: 1 × 16.00 g/mol = 16.00 g/mol
Adding these values together gives us the molar mass of ephedrine:
120.1 g/mol + 15.12 g/mol + 14.01 g/mol + 16.00 g/mol = 165.24 g/mol
Now, we can calculate the number of moles of ephedrine:
Number of moles = Mass / Molar mass
Number of moles = 0.43213 g / 165.24 g/mol
Next, we multiply the number of moles of ephedrine by the molar ratio of water to ephedrine (15:1) to calculate the moles of water produced.
Moles of water = Number of moles of ephedrine × 15
Finally, we can determine the mass of water produced by multiplying the moles of water by the molar mass of water (H2O).
Mass of water = Moles of water × Molar mass of water
By following these calculations, you can determine the mass of H2O produced during the combustion analysis of ephedrine.