Properties of Water: Multiple Choice

______________ is the attraction between molecules of different substances: a. adhesion b. covalent bonding c. cohesion d. ionic bonding

(A) adhesion. An example of adhesion would be the interaction between water molecules and the side of a glass container, the water molecules stick to the sides of a glass container.

Why is water such a good solvent? a. because it is polar b. because it is liquid c. because of its high specific heat capacity d. because of its low specific heat capacity

(A) because water is polar, it can pull apart (or dissolve) compounds more effectively than non-polar solvents.

Water molecules form hydrogen bonds by: a. the attraction between the positive poles of one water molecule with the negative poles of another b. the sharing of electrons between one water molecule and another c. the transfer of electrons between one water molecule and another d. water molecules never form hydrogen bonds

(A) hydrogen bonds are the result of electrical attraction between one end of a polar molecule and another. In the case of water, the negative pole (near the oxygen) is attracted to the positive pole (near the hydrogens) of neighboring water molecules, this attraction is called hydrogen bonding.

Which of the following is a mixture? a. salt and pepper combined in a bowl b. salt dissolved in a glass of water c. sugar dissolved in a mug of tea d. all of the above

(A) salt and pepper combined in a bowl are the only mixture on this list because the are not chemically combined, only physically combined. This is how to distinguish between a mixture and a solution.

In a solution of salt dissolved in water, the water is acting as the __________ and the salt is the ____________. a. solute, solvent b. solvent, solute c. solvent, solution d. solution, solute

(B) the solute is what is being dissolved in the solvent. Water is considered to be an excellent solvent.

Which of the following is FALSE statement about water: a. water is a polar molecule b. more than 50% of our bodies are composed of water c. water is a non-polar molecule d. all of the above statements are false

(C) Water is a polar molecule because the electrons are not evenly shared between the hydrogen and the oxygen. The negative pole is near the oxygen and the hydrogens represent the positive poles.

______________ is the attraction between molecules of the same substance: a. adhesion b. covalent bonding c. cohesion d. ionic bonding

(C) cohesion. The cohesive properties of water allow water droplets to form like beads on a smooth surface (the water molecules like to stick together).

Pure water has a pH of ______. a. 5 b. 6 c. 7 d. none of the above

(C) pure water has a pH of 7, or a neutral pH, meaning it has the same concentration of hydrogen and hydroxide ions.

Mixtures of water and non-dissolved material are called ________________. a. ionic solutions b. covalent solutions c. suspensions d. covalent mixtures

(C) the non-dissolved material in the water remains in suspension, as opposed to dissolving into a solution. Therefore, mixtures of water and non-dissolved material are called suspensions.

The high heat capacity of water allows it to: a. form additional hydrogen bonds b. absorb large amounts of heat energy before the temperature changes c. boil at higher temperatures than many liquids d. B and C

(D) heat capacity refers to the amount of heat energy that is needed in order to change the temperature of a given substance. If water has a high heat capacity, it can absorb a lot of heat energy before it changes temperature, meaning it will also boil at higher temperatures.

The pH scale ranges from 1-14, a lower number on the pH scale would indicate ______ acidity than a higher number. a. lower b. higher c. pH does not have to do with acidity d. equal

(D) higher. The higher the number on the pH scale, the lower the acidity of the solution.

Which of the following is a solution? a. salt dissolved in a tub of warm water b. powdered lemonade mix stirred into a pitcher of water c. sugar dissolved in a mug of hot water d. all of the above

(D) option A-C all represent components which are chemically combined, as opposed to just physically combined. This is how we know they are solutions, as opposed to mixtures.