Question

Dry ice, CO2(s), does not melt at atmospheric pressure. It sublimes at a temperature of −78 °C. What is the lowest pressure at which CO2(s) will melt to give CO2(l)? At approximately what temperature will this occur?

Answer 1

You need to use the equation PV = nRT

The only “trick” in these problems is you need to use the correct UNITS. Especially for the “R” value.

If you get the units (eg temps in Celsius or Kelvin) corresponding to the correct “matching” units of the other variables.

You need to convert the temp into Kelvin first