GRE Subject Test: Chemistry : Solids and Liquids
Study concepts, example questions & explanations for GRE Subject Test: Chemistry
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Example Questions
Example Question #194 : Biochemistry, Organic Chemistry, And Other Concepts
Which of the following describes a transition from gas to solid?
Deposition
Fusion
Crystallization
Vaporization
Sublimation
Deposition
There are six possible phase changes between the three phases of matter. Deposition describes the change from gas to solid, while sublimation describes the transition from solid to gas. Freezing (crystallization) is the transition from liquid to solid, while fusion (melting) is the transition from solid to liquid. Condensation is the transition from gas to liquid, while vaporization (boiling) is the transition from liquid to gas.
Example Question #1 : Phases Of Matter
If you create a perfect vacuum and place a glass of water into the vacuum at room temperature, what will happen to the water?
The water will float about the vacuum
The water will boil
The water will boil very rapidly and then stop
Nothing will happen
The water will freeze
The water will boil
Boiling occurs when the vapor pressure exceeds the air pressure. There is no air pressure in a vacuum, so water at any temperature will boil in a vacuum.
Example Question #2 : Phases Of Matter
Boiling points at standard temperature and pressure:
Methanol-
Toluene-
Water-
Methylene chloride-
Dimethylsulfoxide-
Of the five compounds given, which will have the highest vapor pressure at standard temperature and pressure?
Dimethylsulfoxide
Methanol
Water
Methylene chloride
Toluene
Methylene chloride
A liquid will boil when its vapor pressure increases to match the pressure of its environment. By this logic, a liquid with a higher vapor pressure will be closer to boiling. Liquids with low boiling points thus have greater vapor pressures.
Of the given compounds, methylene chloride has the lowest boiling point, meaning it will also have the highest vapor pressure.
Example Question #1 : Properties Of Liquids
Oil and vinegar is a very popular salad dressing. It also is commonly used for dipping bread. The main component of the oil phase is olive oil, while the main part of the vinegar portion is aqueous acetic acid.
When oil and vinegar salad dressing is allowed to stand at room temperature, two distinct phases are observed. The main explanation for this phenomenon is the difference in _________ of the two phases.
density
acidity
polarity
buoyancy
solubility
polarity
Olive oil, like most oils, is non-polar, while aqueous acetic acid is very polar. These two phases do not mix because of their different solvent polarities.
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