sublimation

What would happen if finger tube is cooled before reducing the pressure?

A layer of condense water will form on it, compromising the deposition process

If there is three states, solid, liquid and gas, why the sample do not melt before becoming gas during the sublimation process?

Because some compounds posses an appreciable vapor pressure at a given temperature

Is sublimation an endothermic or exothermic process?

Endothermic, the sample needs energy to change from solid to gas

What would happen if the pressure is not reduced?

Nothing, we just increase the hot plate temperature to compensate

What would happen if the cooling water is not stopped before collecting the purified sample?

Nothing, you will just waste water

Which one is not a state of matter?

Plasmon

Which kind of technique is sublimation?

Separation / purification

Can sublimation be use with complex mixtures?

Yes if the desired compound has a differentiated vapor pressure in the given conditions

Can an impurity sublimate at the same time than the target compound?

Yes, if it possess an appreciable vapor pressure at that temperature and reduced system pressure

How many states of matter are known?

three

What would happen if you do not warm up your sample?

The sample will slowly be sucked by the suction system

What would happen if the exposed area of the cold finger is humid?

The sample would interact with the water, preventing its crystallization

What would happen if you heat the sample too much?

The sample would melt and, if not stable, decompose

Why the cold finger has to be very close to the sample?

The suction takes part of the sample away; the cold finger at a close distance prevents it

What is the role of the heating plate in the sublimation process?

To provide the energy required in this endothermic process

What is the role of the reduced pressure in the process?

To reduce the sublimation point of the substance since it depends on the system pressure

What is the role of the cold finger in the process?

To reduce the temperature and force the compound's condensation

Which two states of matter are involved in sublimation?

Solid and gas

How would you explain the presence of coloration in the cold finger after collecting a supposedly white compound such as caffeine?

Some impurity is also able to sublimate at the given conditions

What is the vapor pressure of a substance?

The pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system