A 185.325 g sample of a compound of carbon, nitrgoen and hydrogen is burned completely. Calculate the empirical formula if 225.0 g of water and 230.0 g of NO2 is formed. In another experiment the sample was found to have a density of 10.9 g/L at 1.20 atm and 25.0 degrees Celsius. What is the molecular formula of the compound?
Convert 225.0g H2O to g H. Convert 230.0g NO2 to g N.
185.325-gH-gN = gH.
Using moles = grams/atomic mass, convert g C, g H, and g N to moles.
Then find the ratio of each element to each other with the smallest number being 1.00. The easy way to do that is to divide the smallest number by itself, then divide the other numbers by the same small number. Round to whole numbers of multiply by 1, 2, 3, 4, etc to obtain values that are close enough to whole numbers to round to them. That will be the empirical formula.
The molar mass will be given by
Pressure*molar mass = density*R*T
Solve for molar mass.
Finally, the molecular formula is given by (molar mass/empirical mass)n where n is rounded to a whole number.
To determine the empirical formula, we first need to calculate the number of moles of each element present in the compound. Then we can find the ratio of the elements to obtain the empirical formula.
1. Calculate the moles of water (H2O):
- The molar mass of water (H2O) = 2(1.01 g/mol of H) + 16.00 g/mol of O = 18.02 g/mol.
- Moles of water = Mass of water / Molar mass of water = 225.0 g / 18.02 g/mol ≈ 12.48 mol.
2. Calculate the moles of NO2:
- The molar mass of NO2 = 14.01 g/mol of N + 2(16.00 g/mol of O) = 46.01 g/mol.
- Moles of NO2 = Mass of NO2 / Molar mass of NO2 = 230.0 g / 46.01 g/mol ≈ 5.00 mol.
3. Calculate the moles of carbon, nitrogen, and hydrogen:
- Moles of Carbon = ?
- Moles of Nitrogen = ?
- Moles of Hydrogen = ?
To determine the moles of carbon, nitrogen, and hydrogen, we need to use the Law of Conservation of Mass. Since the compound is burned completely, the total mass of the compound before burning must equal the total mass of the products after burning. Therefore:
Total mass of the compound = Mass of carbon + Mass of nitrogen + Mass of hydrogen
We have the mass of the compound (185.325 g), so we can subtract the masses of water and NO2 produced to find the mass of carbon, nitrogen, and hydrogen.
Mass of carbon, nitrogen, and hydrogen = Total mass of the compound - Mass of water - Mass of NO2
= 185.325 g - 225.0 g - 230.0 g
= -269.675 g
Since we obtained a negative value, it suggests a calculation error or that the given data is incorrect. Please double-check the values provided or recalculate the mass of carbon, nitrogen, and hydrogen if there was an error.
Once we have the correct mass percentages of carbon, nitrogen, and hydrogen, we can determine their mole ratios and find the empirical formula. However, without the correct mass values, we cannot proceed to find the empirical formula.
Regarding the molecular formula of the compound, additional information is required. The density of the compound, along with the pressure and temperature, is provided. However, without the molar mass of the compound, we cannot determine the molecular formula.
Please provide the correct or complete information, and we can further assist you.