Chem 12-13 Flashcards
What category includes emulsions, foams, sols, and gel?
Colloid
What is a mixture containing tiny clumps or particles that remain suspended within the mixture and will not settle out?
Colloid
True or false— a catalyst increases the activation energy of a chemical reaction? 4.
False
What type of substance is the scattering of light known as the Tyndall effect a characteristic of ?
Colloid
- True or false— if two substances in the same phase are miscible , they are completely soluble in each other?
True
When a liquid in a closed container reaches a state of equilibrium with its vapor, which of the following is true? 7
The number of molecules evaporating and condensing are equal
What is the attraction of a substance to the surface of a solid called?
Adsorption
What is the total heat absorbed or released when one substance dissolves in another?
Enthalpy of solution
When a solution reaches a state of equilibrium, why does the amount of undissolved solid remain constant?
The rate of crystallization equals the rate of dissolution
What do colligative properties primarily depend upon?
Concentration of the solution
In a solution of glucose in water, what is the glucose?
Solute
- How does increasing concentration usually affect the rate of a reaction?
Increases the rate of reaction
- Describe chain reaction
A chemical reaction in which the products of one reaction step cause other reactions to occur
Describe enzyme
A protein catalyst found in living organisms
Describe inhibitor
A substance that slows down the rate of a reaction
Describe rate-determining step
A reaction in a proposed series that has a greater activation energy than the others and thus occurs more slowly
Describe reaction mechanism
A series of steps describing the way in which a chemical reaction proceeds
Describe solution
A homogeneous mixture of two or more substances
- True/False
If false replace italicized word or in parenthesis to make statement true
The erratic movement of colloidal particles due to random molecular collisions that keep them suspended is known as (Brownian motion)
True
- Substances that dissolve in water to produce ions that can conduct an electrical current are called (colloids).
False - electrolytes
The energy diagram below represents an (endothermic) reaction.
False - Exothermic
- The minimum kinetic energy that a molecule must possess to undergo a chemical reaction is called the (potential) energy.
Activation energy
- Tiny, emulsified droplets of grease or oil suspended in water by soap molecules are (micelles).
True
- A solution that contains as much dissolved solute as possible under equilibrium conditions is (saturated).
True
- When two opposite processes continuously occur at equal rates so that they offset each other, the system is said to be in a state of (balanced) equilibrium.
False - dynamic
- An ion or molecule surrounded by water molecules in aqueous solution is (hydrated).
True
- The quantity of a solute for a given quantity of solution or solvent is known as (concentration).
True
- Which of the following best explains why a catalyst increases the rate of reaction?
It reduces activation energy
- Which of the following best explains the meaning of the phrase “like dissolves like”?
Substances with similar intermolecular forces will dissolve in each other more readily
- At 20 degrees celsious, the rate of a particles reaction is 0.001M/s; what is the rate expected to be at 60 degrees celsious, assuming all other factors remain the same?
0.001-(2)(2)(2)(2)
- Two compartments, labeled “A” and “B,” are separated by a semipermeable membrane. What happens if compartment A is filled with honey (a solution of sugar dissolved in water) and compartment B is filled with distilled water?
There is a net flow of water from B. To A.
- Which of the following combinations is most likely to be completely miscible?
Water and isopropyl alcohol
- Which of the following substances would you expect to be most soluble in a nonpolar solvent such as gasoline?
Water(polar)
- Which of the following is not a colloid?
Sugar water
- When a solid is dissolved in a liquid solvent, does increasing the temperature tend to increase or decrease the solubility of the solid?
Increase
- When a gas is dissolved in a liquid solvent, does increasing the temperature tend to increase or to decrease the solubility of the gas?
Decrease
What term refers to a solution that contains more solute than is ordinarily possible under equilibrium conditions?
Supersaturated
Does adding a nonvolatile solute to a liquid tend to raise or to lower its boiling point?
Raise
- What term refers to a substance that increases the rate of a chemical reaction without being consumed in the reaction?
Catalyst
- Does increasing the temperature of a liquid tend to increase or to decrease its vapor pressure?
Increase
47.. Does adding a nonvolatile solute to a liquid tend to increase or to decrease its vapor pressure?
Decrease
- Calculate the molar its of a solution prepared by dissolving 80.0 g hydrogen fluoride in water to make 500.0mL of solution; the molar mass of HF is 20.01 g/mol.
Q
- A chemist needs to prepare 2.50 L of 0.100 M ammonia. How much concentrated (14.8 M) ammonia does he need?
Q
- Determine the freezing point of a solution containing 50.0 g of sucrose dissolved in 750. g water; round to the nearest 0.01 degrees celsious. See question for more information.
Q
Essay: explain why a can of soft drink would be expected to fizz much more when opened at the peak of Mt. Everest (P atm =260 torr) than when opened at sea level (P atm =760 torr).
Q
What does the field of chemical kinetics involve?
Reaction rate and pathways
