Calculating Moles of Oxygen in a Cylinder

In summary, the problem involves finding the number of moles of oxygen gas in a 20-cm-diameter cylinder with a length of 40 cm and a mass of 50 g at 20 degrees celsius. The correct calculation is 50g/32(g/mol) since oxygen gas is diatomic. It is important to understand if the mass given is for oxygen atoms or diatomic oxygen in order to correctly calculate the number of moles.
  • #1
Renzokuken
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[SOLVED] Converting Mol

1. A 20-cm-diameter cylinder that is 40 cm long contains 50 g of oxygen gas at 20 degrees celsius.

How many moles of oxygen are in the cylinder?




so 1 mol = 6.022*10^23
oxygen atomic mass=16g/mol
50g/16(g/mol) = 3.125 mol


I don't know why it is wrong, someone told me it is 50g/32(g/mol) but why is it 32 instead of 16?
 
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  • #2
Do you mean 50 grams of oxygen gas, or do you mean of oxygen by mass as if all were present counted as the atoms?

You then basically have V, T, you might need R (look for the value in a book);
Actually, the number of moles will not change. You said you have "50 grams", but you did not say as the atoms or as the diatomic gas. You only need to know 1 mole equals 6.02*10^23 units. You need to know if you were given just mass of oxygen atoms or mass of diatomic oxygen.
 
  • #3
ok i get it, i didnt see the gas part. It was talking about O2 thanks
 

1. How do you calculate the number of moles of oxygen in a cylinder?

To calculate the number of moles of oxygen in a cylinder, you will need to know the volume of the cylinder, the pressure of the oxygen gas, and the temperature. Then, you can use the ideal gas law equation (PV = nRT) to solve for the number of moles (n) of oxygen gas present in the cylinder.

2. What is the ideal gas law equation used for calculating moles of oxygen in a cylinder?

The ideal gas law equation (PV = nRT) is used to calculate the number of moles of oxygen in a cylinder. P represents the pressure of the gas, V represents the volume of the cylinder, n represents the number of moles of gas, R is the ideal gas constant, and T represents the temperature in Kelvin.

3. What is the ideal gas constant used in calculating moles of oxygen in a cylinder?

The ideal gas constant (R) is a constant value used in the ideal gas law equation (PV = nRT) to convert between different units of measurement. The value of R depends on the units used for pressure, volume, and temperature. The most commonly used value of R is 0.0821 L·atm/K·mol.

4. Can the number of moles of oxygen in a cylinder change?

Yes, the number of moles of oxygen in a cylinder can change depending on factors such as temperature, pressure, and usage. The ideal gas law equation can be used to recalculate the number of moles when these factors change.

5. How can the number of moles of oxygen in a cylinder be converted to mass?

To convert the number of moles of oxygen in a cylinder to mass, you will need to know the molar mass of oxygen (16 g/mol). Then, you can use the formula mass (g) = number of moles x molar mass (g/mol) to calculate the mass of oxygen present in the cylinder.

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