Question

The temperature of the gas:
The amount of gas in the tube (in terms of mass and moles):
The radius of the tube:
The temperature of the gas (changed by the water surrounding it):
The type of gas:
The pressure of the gas:

Answer 1

I don’t see any numbers in your message — do you want the formulas and procedure to calculate one of these quantities from the others, or do you want me to compute something if you give the values? Below I give the key relations, unit guidance, and things to watch for so you can plug in your values.

Useful formulas and steps

1. Convert mass → moles
- n = m / M
- m: mass of gas (g or kg). M: molar mass (g·mol⁻¹).
- Example units: if m is in grams and M in g·mol⁻¹, n will be mol.

2. Tube volume (cylindrical tube)
- V = π r^2 L
- r: radius (convert to meters for SI). L: length of gas column (m).
- If you only have radius and not length, you must know the filled length of gas in the tube to get V.

3. Ideal gas law (relates P, V, n, T)
- P V = n R T
- R (SI) = 8.314462618 J·mol⁻¹·K⁻¹ (use T in K, P in Pa, V in m³).
- Alternative: R = 0.082057 L·atm·mol⁻¹·K⁻¹ if you use P in atm, V in L, T in K.
- Solve for the unknown: e.g. T = P V / (n R) or P = n R T / V.

4. Temperature of gas changed by surrounding water
- If the gas is in thermal equilibrium with the surrounding water, use the water temperature as the gas temperature (in Kelvin).
- If gas is collected over water, subtract water vapor pressure: P_gas = P_total − P_H2O(T). Use tabulated P_H2O at that temperature.

5. Pressure units and conversions
- 1 atm = 101325 Pa = 760 torr = 1013.25 mbar.
- Make sure P and R use consistent units.

6. Non-ideal behavior
- If pressure is high or temperature low, use a real-gas equation (van der Waals, etc.):
(P + a(n/V)^2)(V − n b) = n R T
- Use appropriate a and b for the gas.

7. Gas identity matters because of molar mass and non-ideal constants
- For common gases: H2 = 2.016 g·mol⁻¹, N2 = 28.014, O2 = 31.999, CO2 = 44.01, He = 4.0026, etc.

What I need from you to compute a specific answer
- Give numeric values (with units) for:
- Mass of gas (or moles directly)
- Gas identity (so I can get M and a,b if needed)
- Tube radius (and length or the gas-filled length)
- Temperature (or water temperature if in equilibrium)
- Pressure (or say whether it’s atmospheric and whether gas collected over water)
- Tell me which quantity you want calculated (e.g., pressure, temperature, moles, volume).

If you give the numbers I’ll perform the calculation and show units and assumptions.