A gaseous compound is 30.4% nitrogen and 69.6% oxygen by mass. A 5.25-g sample of the gas occupies a volume of 1.00 L and exerts a pressure of 1.26 atm at -4.00°C. Which of these choices is its molecular formula?
NO2
The N:O ratio can be obtained by dividing the % mass by the respective atomic masses, namely
N:O = 30.4/14 : 69.6/16 = 2.17:4.35=1:2
Use the 5.25g sample and the ideal gas law to find the molecular mass and hence the composition.
* molar mass
To determine the molecular formula of the gaseous compound, we need to gather all the relevant information and perform the necessary calculations. Let's break it down step by step:
1. Convert the mass percentages into grams:
- Nitrogen (N): 30.4% of 5.25 g = 1.597 g
- Oxygen (O): 69.6% of 5.25 g = 3.653 g
2. Calculate the moles of each element by using their molar masses (grams per mole):
- Moles of N = 1.597 g / molar mass of N
- Moles of O = 3.653 g / molar mass of O
3. To find the molecular formula, we need to determine the ratio of the moles of each element. To do this, divide the moles of each element by the smallest number of moles calculated.
4. Once you have the ratio, we can use it to find the empirical formula of the compound.
However, we are currently missing the molar masses of nitrogen (N) and oxygen (O) to proceed with the calculation. Can you provide the molar masses for nitrogen and oxygen?