If 0.256 g of a compound containing only carbon and hydrogen atoms is burned efficiently and 0.780 g of carbon dioxide and 0.356 g of water are produced, how many moles of H-atoms are contained in the original (0.256 g) sample?
GRAMS OF CARBON:
Mulitiply .780 by percent carbon in CO2, that is grams of carbon. Subtract that from .256g, that is grams of H.
Now divide grams of H by atomicmassH. That is moles of H atoms
Thank you for your help.
To determine the number of moles of hydrogen atoms contained in the original sample, we need to follow a few steps:
Step 1: Calculate the number of moles of carbon dioxide produced.
To do this, we need to convert the mass of carbon dioxide produced (0.780 g) to moles using the molar mass of carbon dioxide.
The molar mass of carbon dioxide (CO2) is calculated by adding the atomic masses of carbon (C) and two oxygen (O) atoms:
Molar mass of CO2 = (1 × atomic mass of C) + (2 × atomic mass of O)
Using the atomic masses of carbon (12.01 g/mol) and oxygen (16.00 g/mol), we can calculate the molar mass of carbon dioxide:
Molar mass of CO2 = (1 × 12.01 g/mol) + (2 × 16.00 g/mol)
Step 2: Calculate the number of moles of water produced.
Similar to step 1, we need to convert the mass of water produced (0.356 g) to moles using the molar mass of water.
The molar mass of water (H2O) is calculated by adding the atomic masses of two hydrogen (H) atoms and one oxygen (O) atom:
Molar mass of H2O = (2 × atomic mass of H) + (1 × atomic mass of O)
Using the atomic masses of hydrogen (1.01 g/mol) and oxygen (16.00 g/mol), we can calculate the molar mass of water:
Molar mass of H2O = (2 × 1.01 g/mol) + (1 × 16.00 g/mol)
Step 3: Calculate the number of moles of carbon in the original sample.
To do this, we need to convert the mass of carbon dioxide produced to the moles of carbon dioxide, and then use the stoichiometry of the equation to determine the moles of carbon.
The balanced chemical equation for the combustion of the compound is:
C(aHb) + (a + b/4)O2 → aCO2 + b/2H2O
From the equation, we can see that for every mole of carbon dioxide produced, there is one mole of carbon. So the number of moles of carbon in the original sample is equal to the number of moles of carbon dioxide produced.
Step 4: Calculate the number of moles of hydrogen in the original sample.
To do this, we need to convert the mass of water produced to the moles of water, and then use the stoichiometry of the equation to determine the moles of hydrogen.
From the balanced chemical equation, we can see that for every mole of water produced, there are two moles of hydrogen. So the number of moles of hydrogen in the original sample is twice the number of moles of water produced.
Finally, we can calculate the moles of hydrogen in the original sample by multiplying the moles of water produced by 2.
By following these steps, you should be able to determine the number of moles of hydrogen atoms contained in the original sample.