chapter 1 chem 2

The flask with the fewest particles, assuming the same temperature

and volume, will experience the lowest pressure.

• TRUE

• FALSE

Answer explanation

The statement you provided is a direct application of the Ideal Gas Law. If the temperature and volume are held constant, a flask with fewer gas particles (or moles) will indeed have lower pressure. This is because the pressure of a gas is directly proportional to the number of its particles in a given volume at a constant temperature. So, fewer particles mean less pressure.

When a substance undergoes a phase change from solid to liquid, the

intramolecular forces binding the molecules weaken.

• True

• False

Answer explanation

When a substance undergoes a phase change from solid to liquid, the intermolecular forces binding the molecules weaken, not the intramolecular forces. Intramolecular forces are the forces that hold the atoms in a molecule together, such as covalent bonds, ionic bonds, and metallic bonds. These forces are very strong and do not change when a substance undergoes a phase change.

-Intermolecular forces, on the other hand, are the forces that bind molecules together. These forces are much weaker than intramolecular forces and can be broken when a substance undergoes a phase change.

Although all molecules with hydrogen bonds exhibit a dipole moment,

not all molecules with dipole-dipole attractions necessarily involve a

hydrogen bond.

• True

• False

Answer explanation

-All molecules with hydrogen bonds exhibit a dipole moment, but not all molecules with dipole-dipole attractions necessarily involve a hydrogen bond.

-Hydrogen bonds are a special type of dipole-dipole attraction that occurs between a hydrogen atom covalently bonded to a very electronegative atom such as N, O, or F and another very electronegative atom.

-Dipole-dipole attractions can occur between any two polar molecules, regardless of whether they contain hydrogen atoms. For example, the molecules of hydrogen chloride (HCl) and carbon dioxide (CO2) both have dipole moments, but they do not form hydrogen bonds.

Assuming consistent pressure, volume, and number of gas particles,

the flask with the highest temperature will exhibit the fastest diffusion

compared to the others.

• True

• False

Answer explanation

-Assuming consistent pressure, volume, and number of gas particles, the flask with the highest temperature will exhibit the fastest diffusion compared to the others. This is because the kinetic energy of gas particles is directly proportional to the temperature of the gas. Gas particles with higher kinetic energy move faster and therefore diffuse faster.

-This can be seen in everyday life. For example, if you open a bottle of perfume in a warm room, the scent will spread throughout the room more quickly than if you opened the bottle in a cold room. This is because the perfume molecules have more kinetic energy in the warm room and therefore move faster.

In the context of ideal gases, intermolecular forces play a significant

role and have an influence on the gas behavior.

• True

• False

Answer explanation

Intermolecular forces play a negligible role in the context of ideal gases. Ideal gases are assumed to have no intermolecular forces, and this assumption is essential for the ideal gas law to be valid.

The physical properties of liquids are influenced by the magnitude of

intermolecular forces.

• True

• False

Answer explanation

The physical properties of liquids are influenced by the magnitude of intermolecular forces. Intermolecular forces are the forces that hold molecules together in a liquid. These forces can be weak (such as London dispersion forces) or strong (such as hydrogen bonds).

Liquids with stronger intermolecular forces have higher melting points, boiling points, viscosity, and surface tension. They also have lower vapor pressure.

Ion-dipole interactions require the presence of polar molecules to

take place.

• True

• False

Answer explanation

Ion-dipole interactions require the presence of polar molecules to take place. A polar molecule is a molecule that has a positive end and a negative end. This is because the molecule has a net dipole moment. A dipole moment is a measure of the separation of positive and negative charges in a molecule

Liquids with stronger intermolecular forces will always have higher

viscosity than those with weaker intermolecular forces.

• True

• False

Answer explanation

While liquids with stronger intermolecular forces will generally have higher viscosity than those with weaker intermolecular forces, there are some exceptions to this rule. For example, water has a higher viscosity than glycerol, even though glycerol has stronger intermolecular forces (hydrogen bonding). This is because glycerol molecules are larger and more complex than water molecules, which makes it more difficult for them to flow past each other.

In a face-centered cubic (FCC) unit cell, atoms are present at the

corners and at the center of each face of the cube.

• True

• False

Answer explanation

-Atoms are present at the corners and at the center of each face of the cube in a face-centered cubic (FCC) unit cell. This arrangement of atoms is known as cubic closest packing, and it is the most efficient way to pack atoms together in a three-dimensional space.

-FCC unit cells are found in many metals, including aluminum, copper, and gold. The FCC structure is responsible for many of the desirable properties of these metals, such as their strength, ductility, and malleability.

Anisotropy is a property often observed in solids where physical

properties depend on the direction due to the absence of specific

arrangement of atoms or molecules.

• True

• False

Answer explanation

Solids that have a random arrangement of atoms or molecules are isotropic, meaning that their physical properties are the same in all directions. Examples of isotropic solids include amorphous solids, such as glass and plastic.