Unit 09 Review

The following reaction takes place in an aqueous solution.

Fe(NO₃)₃ + 3 NaOH → 3 NaNO₃ + Fe(OH)₃

This reaction proceeds to completion because the reverse reaction is prevented by —

• the low temperature of the solution

• the evaporation of the solvent

• the insolubility of NaNO₃

• the insolubility of Fe(OH)₃

Which compounds are both classified as electrolytes?

• NH₄Cl and KCl

• KCl and CH₃OH

• NH₄Cl and C₆H₁₂O₆

• C₆H₁₂O₆ and CH₃OH

Under which conditions of temperature and pressure is a gas most soluble in water?

• Low temperature and high pressure

• High temperature and high pressure

• High temperature and low pressure

• Low temperature and low pressure

Why is water considered to be the "universal solvent"?

• Water is an effective solvent of both polar and nonpolar molecules.

• Water dissolves more chemicals, both inorganic and organic, than any other solvent.

• Water is the only solvent found in abundance throughout the universe.

• Water is an effective solvent in all three phases at standard pressure.

What is the total number of grams of KCl (formula mass = 74.6) in 1.00 liter of a 0.200 molar solution?

Which equation can be used to calculate the dilution of a solution?

• a = bc

• c = λν

• PV = nRT

• M₁V₁ = M₂V₂

A substance is classified as an electrolyte because —

• it has a high melting point.

• its aqueous solution has a pH value of 7.

• its aqueous solution conducts an electric current.

• it contains covalent bonds.

A student attended an event at a traditional tea room that offered sugar cubes instead of sugar packets. She added two sugar cubes to a cup of hot tea. After she finished drinking the tea, she was surprised to see two small chunks of undissolved sugar at the bottom of her cup. All the sugar dissolves in tea of the same temperature when added from a packet. Which of the following BEST explains why sugar remains undissolved from cubes but not from packets?

• The temperature of the tea with cubes was lower than the one with packets.

• Unlike the packet, the cube is compacted so not all sugar molecule surface areas contact the tea.

• Adding a cube decreases the likelihood of stirring the tea, where as adding a packet reminds people to stir.

• Unlike a the tea cup with cubes, tea with packets is served in a bigger cup that allows for more tea.

Water in the bloodstream dissolves —

• cells

• fats

• gases

• viruses

To the nearest gram, what mass of NaCI is needed to produce 1250 mL of a 3.50 M saltwater solution?