FPA Chemistry Test 8 (Ch. 11-12)

Determin the freezing point of a solution containing 50.0 g of sucrose dissolved in 750. g water; round to the nearest 0.01°C. (Kf for water is 1.86°C/m, and the molar mass of sucrose is 342.3 g/mol.) must show work for credit.

-0.36°C

at 20°C, the rate of a particular reaction is 0.001 M/s; what is the rate expected to be at 60°C, assuming all other factors remain the same.

0.016 M/s

what three things are true about the rate-determining steps of a reaction

1. the reaction can proceed no faster than the rate-determining step. 2. the rate-determining step is the slowest step of a multistep reaction. 3. the rate-determining step should be the focus of any attempt to increase the reaction.

a chemist needs to prepare 2.50 L if 0.100 M ammonia. How much concentrated (14.8 M) ammonia does he need? must show work for credit.

16.9 mL

calculate the molarity of a solution prepared by dissolving 85.0 g hydrogen fluoride in water to make 500.. mL of solution; the molar mass of HF is 20.1 g/mol. must show work for credit.

8.46 M

you should know these statements regarding catalysts.

A catalyst increases the rate of a chemical reaction, ∆H for catalyzed and uncatalyzed reactions is the same, and catalysts may be classified as homogeneous and heterogeneous.

the erratic movement of colloidal particles due to random molecular collisions that keep them suspended is known as this

Brownian motion

When a liquid in a closed container reaches a state of equilibrium with its vapor, what can be said of it.

The number of molecules evaporating and condensing are equal.

name the short-lived unstable arrangement of atoms that molecules are thought to form as they collide and chemically react

activated complex

what the attraction of a substance to the surface of a solid called

adsorption

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). 10 pts

answers will vary.

a chemical reaction in which the products of one reaction step cause other reactions to occur

chain reaction

what is a mixture containing tiny clumps or particles that remain suspended within the mixture and will not settle out

colloid

What type of substance is the scattering of light known as the Tyndall effect a characteristic of.

colloids

this category includes emulsions, foams, sols, and gels

colloids

the quantity of a solute for a given quantity of solution or solvent is known as...

concentration

what do colligative properties primarily depend upon

concentration of the solution

does adding a nonvolatile solute to a liquid tend to increase or to decrease its vapor pressure

decrease

when a solid is dissolved in a liquid solvent, does decreasing temperature tend to increase or to decrease the solubility of the solid.

decrease

when two opposite processes continuously occur at equal rates to that they offset each other, the system is said to be in a state _______ equilibrium

dynamic

substances that dissolve in water to produce ions that can conduct an electrical current are called this

electrolytes

what is the total heat absorbed or released when one substance dissolves in another

enthalpy of solution

a protein catalyst found in living things

enzyme

the energy diagram represents what kind of reaction

exothermic

term that describes a platinum mesh used to break down petroleum vapors into smaller molecules

heterogeneous catalyst

an ion or molecule surrounded by water molecules in aqueous solution is this.

hydrated

does increasing the temperature of a liquid tend to increase or to decrease its vapor pressure

increase

when a gas is dissolved in a liquid solvent, does decreasing temperature tend to increase or to decrease the solubility of the gas.

increase

how does increasing concentration usually affect the rate of a reaction

increases the rate of reaction by increasing the frequency of collisions

a substance that slows the rate of a reaction

inhibitor

statement that best explains why a catalyst increases the rate of a reaction

it reduces activation energy

tiny, emulsified droplets of grease or oil suspended in water by soap molecules

micelles

which of the following substances would you expect to be most soluble in a nonpolar solvent such as gasoline. [ ammonia (polar), paraffin (nonpolar), water (polar), or all are equally soluble.]

paraffin (nonpolar)

does adding a nonvolatile solute to a liquid tend to raise or to lower its boiling point

raise

in a chemical reaction, the change in concentration of a substance divided by the time for the change is the reaction _____.

rate

a reaction in a proposed series that has a greater activation energy than the others and thus occurs more slowly

rate-determining step

a series of steps describing the way in which a chemical reaction proceeds

reaction mechanism

the field of chemical kinetics involve these

reaction rates and pathways

a solution that contains as much dissolved solute as possible under equilibrium conditions

saturated

in a solution of glucose in waster, what is the glucose

solute

a homogeneous mixture of two or more substances

solution

statement that best explains the meaning of the phrase " like dissolves like"

substances with similar intermolecular forces will dissolve in each other more readily

which of the following is not a colloid. [ sugar water, milk, aerogel, or smoke]

sugar water

what term refers to a solution that contains more solute than is ordinarily possible under equilibrium conditions

supersaturated

statement that best explains why the following reaction is not likely to occur in a single step. 2C₆H₆(l) + 15O₂(g) → 12CO₂(g) + 6H₂O(g)

the 17-body collision required is extremely unlikely

the minimum kinetic energy that a molecule must possess to undergo a chemical reaction is called

the activation energy

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

two compartments, labeled "A" and "B", are separated by a semipermeable membrane. what happens is 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

What is true of two substances in the phase are miscible

they are completely soluble in each other

which of the following combinations is most likely to be completely miscible? water and oil, isopropyl alcohol and oil, water and isopropyl alcohol or none will be completely miscible.

water and isopropyl alcohol