Liquid Ethylene Density Calculator

Related Calculators

Liquid density: Mass per unit volume of liquid ethylene. Higher density means the same mass takes up less space.

Specific volume: Volume per unit mass. It is the reciprocal of density, so a smaller specific volume means a denser liquid.

Saturation pressure: The pressure at a given temperature where a pure substance's liquid and vapor can exist in equilibrium [2].

Saturated liquid: A liquid state that is at or very near the saturation pressure for the entered temperature.

Compressed liquid: A liquid at a pressure above the saturation pressure for the same temperature.

Absolute pressure: Pressure measured from zero pressure. This is the pressure needed for thermodynamic state checks.

Gauge pressure: Pressure measured above the surrounding air pressure, so it must be converted to absolute pressure before the calculator checks phase.

Mistake: Entering gauge pressure into "Pressure (bar abs)" while leaving "Pressure type" on absolute.
Fix: If your pressure is gauge pressure, switch "Pressure type" to gauge so the calculator adds standard atmospheric pressure before the state check.

Mistake: Typing a temperature in K or deg F into "Temperature (deg C)" without changing "Temperature unit".
Fix: Set "Temperature unit" to match your entry, or convert your number to deg C before calculating.

Mistake: Using "Mass" and "Volume" from different unit systems but forgetting to change "Mass unit" or "Volume unit".
Fix: Make sure "Mass unit" and "Volume unit" exactly match what you measured before trusting "Liquid density".

Mistake: Treating a pressure comparison as independent validation of the density. Fix: The calculator converts your supplied property. Obtain it from a validated source for the exact temperature, absolute pressure, and liquid phase.

Mistake: Entering zero or negative "Volume" or "Mass" in measured mode.
Fix: Use a positive "Mass" and a "Volume" greater than zero, then recalculate to get a physical "Liquid density" and "Specific volume".

Mistake: Assuming "Saturation pressure at this temperature" is your actual tank pressure.
Fix: Compare your entered pressure to "Saturation pressure at this temperature". That output is the phase-change pressure at the entered temperature, not a measured system pressure.

• The temperature-and-pressure path converts a supplied liquid property; it contains no predictive density correlation. Confirm the property at the exact conditions and liquid phase in a validated source. The optional saturation comparison is restricted to temperatures between the triple and critical points.
• If the entered pressure is below the saturation pressure at the entered temperature, pure ethylene is not treated as a stable liquid here, so the liquid-density estimate should not be used.
• Near the critical region, liquid and vapor become harder to separate and small input changes can cause large property changes, so results are more sensitive.
• If you choose gauge pressure, the calculator converts it using standard atmosphere of 1.01325 bar; real local atmospheric pressure can differ slightly.
• The mass-and-volume path gives measured density only. It does not prove the sample is pure ethylene or fully liquid.
• Unit conversions are applied after the core calculation, so wrong unit selections can cause large errors even when the math is correct.

Core calculation paths

The calculator uses one of two methods depending on your choice in "What do you want to use?".

ρ (density) = m / V

v (specific volume) = 1 / ρ

In measured mode, mass is first converted to kg and volume to m3, then density is calculated in kg/m3 and converted to the result unit you picked.

In temperature-and-pressure mode, the calculator converts your supplied density and calculates its reciprocal. If a verified saturation pressure is entered, it compares absolute pressure with that value. It does not independently calculate density or establish the phase.

Pressure conversion and phase check

P_abs = P_gauge + P_atm

if P_abs < P_sat(T), state = not liquid

if |P_abs - supplied P_sat| / supplied P_sat <= tol, pressure is near saturation; phase fraction is unknown

if P_abs > supplied P_sat, pressure is above saturation; verify the liquid property in its source

Here, P_atm is standard atmosphere, 1.01325 bar. The optional supplied saturation pressure must match the entered temperature. The tolerance flags a pressure near saturation; it does not identify a fully liquid state.

Temperature-pressure density estimate

Use a validated property source, such as NIST fluid data, to obtain density at the entered temperature and absolute pressure. No assumed linear temperature slope is used.

ρ = supplied verified liquid density at the entered T/P

For example, supplying a verified density of 568 kg/m3 gives 0.568 g/mL and a specific volume of 1/568 m3/kg. This illustrates conversion only; it does not assert that 568 kg/m3 applies at the default T/P.

Mini example

If you choose measured mode with 5 kg and 8.8 L, the calculator converts 8.8 L to 0.0088 m3 and then computes density as 5 / 0.0088 = 568.18 kg/m3. Specific volume is then 1 / 568.18 = 0.00176 m3/kg.

Assumptions behind the result

Measured density assumes mass and volume refer to the same sample and condition. Supplied-property mode assumes the user has obtained a valid liquid-phase density at the specified temperature and pressure; it does not validate the source or predict the property. Use a validated equation of state for engineering work.