Review #5 (Solutions)

How does a pure substance differ from a mixture?

• Every sample of a mixture has exactly the same composition
• Every sample of a pure substance has exactly the same composition
• Mixtures are either compounds or elements
• Pure substances can be separated into components

One way the mixtures differ from compounds is that mixtures

• Are not composed of elements
• Are not pure substances
• Cannot be broken down through physical changes
• Can sometimes be separated by filtrations

How does temperature affect solubility?

• A rise in temperature always increases solubility
• A rise in temperature always decreases solubility
• Gas solubility decreases with higher temperatures, which the solubility of solids usually increases
• Temperature does not affect solubility in any consistent way

Saltwater is an example of a 

• molecule
• solvent
• heterogeneous mixture
• homogeneous mixture

How does breaking up a sugar cube that sits on the bottom of the glass affect its ability to dissolve in your iced tea?

• Breaking it up increases the surface area and thus increases the solubility
• Breaking it up increases the surface area and speeds up the dissolving
• Breaking it up without stirring has no effect on the dissolving process
• Unless you also heat the iced tea, breaking the sugar cube up has no effect on the dissolving process

Why must divers consider gas solubility?

• The cold temperatures they encounter on their dives can dangerously increase the dissolved gas in their bodies.
• The extreme pressure they encounter on their dives can dangerously decrease the dissolved gas in their bodies.
• If they surface too quickly, gas solubility increases dangerously fast
• Diver's can't breathe if their blood dissolves too much air during the dives

According to ________, sugar dissolves in water because particles are in motion and bump into each other.

• the law of conservation of energy
• Le Chatelier's principle
• the law of definite proportions
• kinetic theory

One electrolytic solution has twice the conductivity of a second electrolytic solution of equal concentration and volume.  Which of the following is NOT a possible explanation for this?

• The electrolyte in the first sample is twice as strong as the second
• The two samples contain equal amounts of solute
• The acid in the first sample is twice as strong as the second
• The first sample contains twice as much water

Why would an antacid, such as aluminum hydroxide, be used to treat heartburn?

• the basicity of aluminum hydroxide would neutralize the acidity of the stomach
• aluminium hydroxide is an acid that neutralizes the basicity of the stomach
• Aluminum hydroxide is a salt that neutralizes the basicity of the stomach
• none of the above

Which of these has a high pH?

• battery acid
• coffee
• apple juice
• ammonia