chapter 12 knweton homework

Which will freeze at the lowest temperature? A). pure bottled water B). tap water C). ocean water D). these will freeze at the same temperature

Ocean water has the highest concentration of solute, so it will have the greatest freezing point depression, and therefore freeze at the lowest temperature of the three.

Which of the following react most rapidly? Ground beef spoiling in a freezer Calcium exposed to water Iron train tracks exposed to the air overnight Small pieces of elemental sodium exposed to the air overnight

Small pieces of elemental sodium exposed to the air overnight

A catalyst lowers the activation energy of a reaction by providing an alternate pathway or mechanism reducing the energy stored in the bonds of the reactants increasing the electrostatic attraction between the reactants none of the above

providing an alternate pathway or mechanism

If a small volume of a particular liquid was to react with the oxygen in the atmosphere, which container would allow for the reaction to occur the most quickly? test tube beaker dish no difference in rate

dish

Which is an example of CONCENTRATION affecting the rate of reaction? Calcium reacts with water moderately while sodium reacts with water explosively. Food spoils more quickly on the kitchen counter than in the fridge. The smaller the piece of wood, the faster it burns. A reaction slows down as it proceeds

A reaction slows down as it proceeds.

Which is an example of the chemical nature of substances affecting the rate of reaction? A). sodium oxidizes overnight whereas iron takes much longer B). large pieces of iron react slowly with acids while finely divided iron reacts more rapidly C). food spoils more quickly on the kitchen counter than in the fridge D). all of the above

A).

Identify the option below that increases the rate of a reaction. Maintaining a reaction temperature that is just warm enough to allow the reaction to proceed over the course of a day Decreasing the concentration of the reactants Allowing some solvent to evaporate from the vessel containing a reaction that takes place entirely in solution Decreasing the temperature of a reaction to 10 K

Allowing some solvent to evaporate from the vessel containing a reaction that takes place entirely in solution

Which of the following gives the definition of elementary reaction? An elementary reaction is a reaction involving the collision and combination of exactly two reactant species. An elementary reaction is a reaction that takes place on a molecular scale precisely as depicted in its chemical equation. An elementary reaction is a reaction involving the simultaneous collision and combination of three reactant species. An elementary reaction is a reaction involving the rearrangement of a single reactant species to produce one or more molecules of product.

An elementary reaction is a reaction that takes place on a molecular scale precisely as depicted in its chemical equation.

The process by which pressure greater than osmotic pressure is applied to a solution to drive solvent molecules from the solution into the pure solvent is called A). inverted osmosis B). .reverse osmosis C). pure osmosis D). osmotic inversion

B

The surface area of a substance affects the rate of reaction when the reaction is occurring between a: A). solid and liquid B). liquid and gas C). solid and gas D). all of the above

D

Which of the following is false? A reaction mechanism is the pathway by which a reaction occurs. Elementary reactions can often be broken down into simpler steps. Elementary reactions occur exactly as written. Reactive intermediates are produced in one step and consumed in a subsequent step.

Elementary reactions can often be broken down into simpler steps.

Which is NOT a postulate of collision theory? The rate of a reaction is proportional to the rate of reactant collisions. The reacting species must collide in an appropriate orientation. The collision between particles must occur with adequate energy. Every reaction must involve the collision of two molecules.

Every reaction must involve the collision of two molecules.

Which of the following is the term for a stepwise sequence of elementary reactions by which a chemical change takes place? Rate law Reaction order Reaction mechanism None of the above

Reaction mechanism

The chemical nature of an element is determined largely by its: period number group number atomic mass atomic number

The group, also know as the column, that an element is in on the periodic table will determine many of its characteristics, including its rate of reaction in certain processes

Which of the following illustrates how the degree of subdivision of the reactants affects the rate of reaction? A certain reaction does not proceed until the reactants are placed on a hot plate. A wooden headboard burns more quickly in a fire than an iron headboard. Zinc shavings react more quickly with acid than an equivalent mass of solid zinc in one large block. When exposed to air, sodium reacts completely overnight, while iron barely reacts at all.

Zinc shavings react more quickly with acid than an equivalent mass of solid zinc in one large block. A finely divided solid has more surface area available for reaction and thus reacts more rapidly than a larger piece of the same substance.

Which is an example of concentration affecting the rate of reaction? a reaction proceeds more quickly in the laboratory when placed over a Bunsen burner a solution containing two moles of each reactant has a faster instantaneous rate of reaction than a solution of the same volume with only one mole of each reactant sodium oxidizes overnight whereas iron takes much longer large pieces of iron react slowly with acids while finely divided iron reacts more rapidly

a solution containing two moles of each reactant has a faster instantaneous rate of reaction than a solution of the same volume with only one mole of each reactant These solutions clearly have differing concentrations of reactants, and they will therefore exhibit differing initial rates.

Which of the following actions increases the rate of a chemical reaction? (select all that apply) adding a catalyst lowering the activation energy increasing the concentration of a first order reactant increasing the temperature

adding a catalyst lowering the activation energy increasing the concentration of a first order reactant increasing the temperature

Which is an example of the chemical nature of substances affecting the rate of reaction? a reaction proceeds more quickly in the laboratory when placed over a Bunsen burner a solution containing two moles of each reactant has a faster instantaneous rate of reaction than a solution of the same volume with only one mole of each reactant calcium reacts with water moderately, sodium can react explosively with water large pieces of iron react slowly with acids while finely divided iron reacts more rapidly

calcium reacts with water moderately, sodium can react explosively with water

In the following equation, A and B are _______________, and N2O2 is an ______________: Overall: 2NO+O2⟶2NO2 A: 2NO⟶N2O2 B: N2O2+O2⟶2NO2 elementary reactions; intermediate intermediates; elementary reaction reaction mechanisms; elementary elementaries; reaction mechanism

elementary reactions; intermediate A and B are elementary reactions, as they are the steps within a reaction mechanism. Elementary reactions occur exactly as they are written and cannot be broken down into simpler steps. N2O2 is an intermediate because it is produced in one step and consumed in a subsequent step.