Help with Properties of Solids

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AP Chemistry › Help with Properties of Solids

Questions 1 - 8
1

Which of the following properties will decrease as a solute is dissolved in a liquid?

Freezing point

Temperature

Boiling point

Osmotic pressure

Explanation

Dissolving a solute in a solvent increases the number of dissolved particles per mass of solvent. Freezing point depression is a colligative property of solutions, and will decrease as the molality of the solution increases. Boiling point and osmotic pressure increase as the molality of the solution increases. Temperature is unaffected by the dissolution of solutes in a solvent.

2

Which of the following statements concerning the properties of solids are true?

All of these

Solids are incompressible

Solids can either be crystalline or amorphous

Solids have definite shapes and volumes

Solids generally have very strong intermolecular forces

Explanation

Solids have well defined shapes because their atoms are held tightly together, only allowing localized movement. Because a solid's atoms are so close together, solids are incompressible. There so little space between atoms that they can't get any closer together. The reason a solid's atoms are so close together is they experience strong intermolecular forces, resulting in high stability. Solids can either be crystalline or amorphous in structure. Crystalline structure is regimented and grid-like, while amorphous has no regular, repeating pattern of atoms.

3

Which of the following is a property of crystalline solids?

Atoms are locked together in a repetitive pattern

Atoms move about randomly

Atoms move about to fill their container

None of these

Explanation

A crystalline solid is made up of a repeating pattern of atoms called a crystal lattice. Atoms moving about randomly, and taking the shape of their container are descriptions of fluids (liquids and gasses).

4

Which of the following is a property of a solid?

Molecules are held together in fixed positions

Samples of solids have indefinite shapes and volumes

Molecules can freely move past one another

Molecules are not touching one another

Samples of solids have indefinite shapes but definite volumes

Explanation

Solids are defined as having definite shapes and volumes. The atoms in a solid touch one another and are fixed in rigid positions. Unlike liquids or gases, molecules inside a solid are not able to freely move past one another. Solids will retain their shape even when put in open atmospheres.

5

Which of the following is not a characteristic of solid elemental aluminum?

High-density metal

Good conductor of electricity

Good conductor of heat

Ductile

Malleable

Explanation

Aluminum is not a high-density metal. You may figure this out by comparing aluminum's density (2.7 g/mL) to the density of other metals. Aluminum is very lightweight compared to other metals, making it ideal for the construction of things like airplanes.

Aluminum is a good conductor of heat and electricity. It is ductile, meaning it can be turned into wire, and it is malleable, meaning it can be made into sheets.

6

Which of the following correctly describes a solid?

Definite volume and definite shape

Definite volume, but not definite shape

Definite shape, but not definite volume

Neither definite shape, nor definite volume

None of these define a solid

Explanation

A solid is defined as having a definite shape and definite volume. A liquid is defined as having a definite volume, but not a definite shape. A gas is defined as neither having a definite shape nor a definite volume.

7

Which of the following is a difference between amorphous and crystalline solids?

Amorphous solids do not have a repetitive pattern of atoms, crystalline solids do

Crystalline solids do not have a repetitive pattern of atoms, amorphous solids do.

Amorphous solids constantly change shape, crystalline solids do not

Amorphous solids are intermediaries between liquids and true (crystalline) solids

Explanation

Crystals, or crystalline solids consist of repeated, regular pattern of atoms known as a crystal lattice. Amorphous solids do not have a lattice, and consist of a mass of atoms without a repeated pattern.

8

Which of the following best explains why salt is scattered on icy roads and sidewalks?

The salt lowers the freezing point of the ice, making it easier to clear or navigate safely

The salt raises the freezing point of the ice, making it easier to clear or navigate safely

The salt gives extra traction for walkers and drivers

The salt lowers the boiling point of the ice, making it more likely to sublimate

Explanation

The salt decreases the freezing point of the water. Upon addition of salt to icy roads and sidewalks, the ice melts, making it safer to drive and walk. Freezing point depression is a colligative property and depends on the number of dissolved particles, not the type of particles. Thus, sugar would also decrease the freezing point of ice. The amount the freezing point decreases is proportional to the number of dissolved solutes in the solution.

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