U10 HChem Properties of Water, Electolytes

Multiple Choice

Rank the following from weakest to strongest: covalent bond, dipole-dipole, hydrogen bond, ionic bond, London dispersion forces (LDFs).

• London dispersion forces (LDFs), dipole-dipole, hydrogen bond, covalent bond, ionic bond

• Ionic bond, covalent bond, hydrogen bond, dipole-dipole, London dispersion forces (LDFs)

• Covalent bond, ionic bond, hydrogen bond, dipole-dipole, London dispersion forces (LDFs)

• Hydrogen bond, dipole-dipole, covalent bond, ionic bond, London dispersion forces (LDFs)

Hotspot

Identify which choice is a hydrogen bond

Hotspot

Click on the polar covalent bond

Multiple Choice

Which atom in a water molecule is the most electronegative?

• Hydrogen

• Oxygen

• Nitrogen

• Carbon

Multiple Select

Which of the following statements about water are correct?

• Water has a bent molecular shape.

• Water is a nonpolar molecule.

• Water can form hydrogen bonds.

Multiple Choice

What is surface tension in water primarily caused by?

• Electrostatic attraction between ions

• Hydrogen bonding between water molecules

• Covalent bonding within water molecules

• Van der Waals forces

Multiple Choice

 Small insects can walk across the surface of calm water. Their feet push the surface of the water down slightly, somewhat like a person walking across a trampoline, but they do not break the surface. What is the best explanation for why this happens?

• The insects are light enough so that they do not break the hydrogen bonds holding the water molecules together
• The insects actually use their wings to hover slightly above the water's surface and they only skim it with their feet
• The insects' feet are non-polar, so they are repelled by the polar water molecules and are pushed away from the water's surface
• The insects are small enough to see the individual water molecules, so they are able to step carefully from one molecule to the next

Multiple Choice

Which of the following best describes the role of a surfactant in water?

• It increases hydrogen bonding and raises surface tension.

• It interferes with hydrogen bonding and reduces surface tension.

• It decreases hydrogen bonding and increases surface tension.

• It does not affect hydrogen bonding or surface tension.

Multiple Choice

What explains the very high melting and boiling point of water

• Strong dipole-dipole bonds between water molecules
• Strong hydrogen bonds between water molecules
• Dispersion forces which are present in all molecules
• Asymmetrical shape of the polar bonds.

Multiple Choice

Large bodies of water, such as lakes and oceans, do not quickly fluctuate in temperature. What is the reason for this phenomenon?

• Water is an acid.
• Water is a versatile solvent.
• Water has a high heat capacity.
•  Water acts as a buffer.

Multiple Choice

What is the main reason ice floats on water?

• Ice is less dense than liquid water due to its molecular arrangement.

• Ice is more dense than liquid water due to its molecular arrangement.

• Ice and water have the same density.

• Ice contains more hydrogen bonds than liquid water.

Multiple Choice

Which of the following statements about water's density is correct?

• Water is less dense as a liquid than as a solid.

• Water is more dense as a liquid than as a solid.

• Water and ice have the same density.

• Water vapor is denser than liquid water.

Multiple Choice

When a substance dissolves in water, we say that this substance is:

• insoluble

• only ionic

• soluble

Multiple Choice

When a substance will not dissolve in water:

• soluble

• insoluble

• ionic

• molecular

Multiple Choice

Why is pure water rarely found in nature?

• Because water is the universal solvent and dissolves other compounds easily.

• Because water is always contaminated by pollutants.

• Because water evaporates quickly.

• Because water is only found in oceans.

Multiple Choice

In a saltwater solution, what is the role of water?

• Solute

• Solvent

• Solution

• Compound

Multiple Choice

What role do water molecules play in the dissolution of sodium chloride (NaCl)?

• They provide kinetic energy and attract ions.

• They form a precipitate with NaCl.

• They prevent NaCl from dissolving.

• They evaporate quickly.

Multiple Choice

Why do some ionic substances form insoluble precipitates in water?

• Because the attraction between ions is stronger than the attraction between ions and water

• Because water cannot interact with any ions

• Because all ionic substances dissolve well in water

• Because precipitates are always soluble

Multiple Choice

In general, which types of compounds dissolve easily in water?

• Polar and Nonpolar
• Polar and Ionic
• Nonpolar and Ionic
• Covalent and Nonpolar

Multiple Choice

Which of the following is LEAST likely to dissolve in water?

• nonpolar fats and oils
• polar sugar molecules
• salt made of a positive sodium ion and a negative chloride ion
• all of the substances will dissolve easily in water

Multiple Choice

Solutions that conduct electricity are called _________.

• ionized

• shocking

• non-electrolytic

• electrolytic

Multiple Choice

In order for a solution to be an electrolyte, the solute must

• be a molecular compound.

• restrict the flow of electricity.

• create a saturated solution.

• consist of positive and negative ions

Multiple Choice

A solid substance was tested in the laboratory. The test results are listed below.

• dissolves in water

• is an electrolyte

• melts at a high temperature

Based on these results, the solid substance could be

• Cu

• CuBr₂

• C

• C₆H₁₂O₆

Multiple Choice

Which of the following is not an electrolyte?

• KBr

• LiOH

• RbNO₃

• CH₄