What can be said about a substance with a triple point above 1atm

1) The liquid state of the substance cannot exist.
2) The gaseous state at 1 atm pressure cannot be condensed to the solid at the triple point temperature.
3) The melting point of the solid must be greater than 0 C.
4) The liquid state cannot be maintained in a beaker open to air at 1 atm pressure.
5) The melting point and boiling point of the substance are identical.

6) The solid and liquid states of the substance cannot coexist at equilibrium.

I know triple point is when solid, liquid, and gas coexist. However, what is special about that if the pressure is higher than 1atm? I was thinking 2) because I found online that "Triple point lies above 1 atm, implying that
liquid CO2 cannot exist at normal
pressures"

but I'm not sure if that's correct.

You are correct! If the triple point of a substance is above 1 atm, it means that the substance cannot exist in its liquid state at normal atmospheric pressures. So, statement 1 is true.

However, statement 2 is not entirely accurate. The triple point is the specific combination of temperature and pressure at which all three phases of a substance (solid, liquid, and gas) can coexist in equilibrium. If the pressure is greater than 1 atm, it doesn't necessarily mean that the gaseous state cannot be condensed to the solid state at the triple point temperature. The ability to condense or vaporize the substance at the triple point depends on the conditions and the properties of the substance.

Statement 3 is not necessarily true either. The melting point of the solid doesn't have to be greater than 0°C if the triple point is above 1 atm. The melting point of the solid is defined as the temperature at which it changes from solid to liquid at a specific pressure. The triple point, however, refers to a specific combination of temperature and pressure, and the melting point can be different from the triple point temperature.

Statement 4 is also not entirely accurate. While it is true that the liquid state cannot be maintained in a beaker open to air at 1 atm pressure if the substance's triple point is above 1 atm, it doesn't mean that the liquid state cannot exist at all. It just implies that special conditions are required to maintain the substance in its liquid state at normal atmospheric pressures.

Statement 5 is unrelated to the concept of a triple point. The melting point and boiling point of a substance do not have to be identical for the substance to have a triple point.

Finally, statement 6 is true. If the triple point of a substance is above 1 atm, it means that its solid and liquid states cannot coexist at equilibrium at normal atmospheric pressures.

In summary, the only correct statement in this context is statement 6.

If the triple point of a substance is above 1 atm, it means that at atmospheric pressure (1 atm), the substance cannot exist in its liquid state. This implies that option 1) The liquid state of the substance cannot exist is correct.

At the triple point, all three phases (solid, liquid, and gas) coexist in equilibrium. However, if the pressure is above 1 atm, the substance will not be able to condense from the gaseous state to the solid state at the temperature of the triple point. Therefore, option 2) The gaseous state at 1 atm pressure cannot be condensed to the solid at the triple point temperature is also correct.

Regarding the other options:
3) The melting point of the solid must be greater than 0°C: The melting point being greater than 0°C is not related to the triple point.

4) The liquid state cannot be maintained in a beaker open to air at 1 atm pressure: This statement is not necessarily true as it depends on the substance and its specific properties.

5) The melting point and boiling point of the substance are identical: The melting point and boiling point being identical does not have a direct relationship to the triple point.

6) The solid and liquid states of the substance cannot coexist at equilibrium: This statement is true for substances at their triple point, regardless of the pressure. However, it does not specifically address the pressure being above 1 atm.

Therefore, the correct statements for a substance with a triple point above 1 atm are 1) The liquid state of the substance cannot exist and 2) The gaseous state at 1 atm pressure cannot be condensed to the solid at the triple point temperature.