Chem 101

HF+NH3⇌F−+NH+4 Which of the above chemical species is the Brønsted-Lowry base?

NH3

A system involves a chemical reaction that is exothermic in the forward direction. How will the equilibrium shift if the temperature of the system is decreased?

The equilibrium will shift towards the products.

If the forward reaction of an equilibrium is endothermic, the ΔH will have a _______ sign, and the heat can be thought of as a _________.

positive, reactant

A catalyst will-

reduce the activation energy of a reaction

In order for an equilibrium to develop, a reaction must be:

reversible

An increase in temperature of ten degrees Celsius will have what effect on the rate?

depends on the reaction

The rate of a reaction usually increases as temperature _________________ and concentration ________________.

increases, increases

Identify which of the following would be insoluble.

AgCl

Which of the following compounds would form a precipitate in solution? LiNO3 AlPO4 CsBr RbHCO3

AlPO4

Strong acids are paired with:

weak conjugate bases.

Which of the following will burn the fastest? Select the correct answer below: A 2-pound log at 50∘C A 2-pound log at 0∘C A 2-pound log at room temperature Each will react at the same rate.

A 2-pound log at 50∘C

Identify the options below that are examples of concentrations of reactants affecting the rate of a reaction. (select all that apply)

A 5 M sample of hydrogen peroxide decomposes at a faster rate than a 2 M sample of the same volume. Calcium carbonate deteriorates more rapidly in polluted air than in clean air.

Which is an example of concentration affecting the rate of reaction? Select the correct answer below: 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.

Of the following, which is a false statement regarding chemical equilibrium?

A reversible reaction means a reaction that is at equilibrium between reactants and products.

Which description best fits the definition of activated complex?

An activated complex is an unstable combination of reactant species representing the highest energy state of a reaction system.

Which of the following react relatively slowly (hours to years) rather than nearly instantaneously? (select all that apply)

An egg spoiling in a freezer Calcium exposed to water Iron train tracks exposed to the air

Which of the following illustrates how the intrinsic chemical properties of a reactant affect reaction rate? (select all that apply)

Calcium reacts with water at a moderate rate to form hydrogen gas and a base, whereas sodium reacts in a similar way in mere seconds. A wooden headboard burns more quickly in a fire than an iron headboard.

Identify the options below that are false about chemical equilibria. (select all that apply)

Concentrations of products and reactants oscillate between a set range of values. At equilibrium, all species have stopped reacting altogether.

Which of the following decreases the rate of a reaction? Select the correct answer below: Decreasing the concentration of a reactant that does not appear in the rate law Heating up the reaction vessel on a hot plate Taking a break after continuously stirring a very slow reaction for half an hour Decreasing the concentration of a first order reactant

Decreasing the concentration of a first order reactant

Identify the options below that decrease the rate of a reaction. (select all that apply)

Decreasing the temperature of an endothermic reaction Decreasing the concentration of a second order reactant

Which of the following is an example of reactant concentration affecting the rate of a reaction? Select the correct answer below: A wooden table burns more quickly in a fire than an iron headboard. Five 4-inch diameter saplings burn more rapidly than a 20-inch tree of the same height. Phosphorus burns much more rapidly in an atmosphere of pure oxygen than in air, which is about 21% oxygen. Food spoils more quickly on a kitchen counter than in a refrigerator.

Phosphorus burns much more rapidly in an atmosphere of pure oxygen than in air, which is about 21% oxygen.

All of the following are examples of the temperature of reactants affecting the rate of a reaction except:

Phosphorus burns much more rapidly in an atmosphere of pure oxygen than in air.

A small amount of product is removed from a system at equilibrium. Which of the following will change? Select all that apply.

The amount of reactants The value of Q

Identify the options below that are results of decreasing the temperature of a system that includes an exothermic reaction in the forward direction.

The concentrations of the products increase. The equilibrium shifts toward the products.

Choose the options below that are true of chemical equilibria. (select all that apply)

The reaction proceeds in the forward and reverse directions at the same rate. Both the forward and the reverse reactions are achievable. There is no net change in concentrations of reactants and products.

A small amount of reactant is removed from a system at equilibrium. Which of the following will change?

The value of Q

The correct order, from slowest to fastest, according to the rate of reaction of each with sulfuric acid is: _______. Select the correct answer below: a 5-pound iron pipe; 5 pounds of iron shavings; 5 pounds of iron powder; a 5-pound iron cube a 5-pound iron cube; a 5-pound iron pipe; 5 pounds of iron shavings; 5 pounds of iron powder a 5-pound iron cube; 5 pounds of iron shavings; a 5-pound iron pipe; 5 pounds of iron powder a 5-pound iron pipe; 5 pounds of iron powder; 5 pounds of iron shavings; a 5-pound iron cube

a 5-pound iron cube; a 5-pound iron pipe; 5 pounds of iron shavings; 5 pounds of iron powder

Which is an example of temperature affecting the rate of reaction?

a reaction proceeds more quickly in the laboratory when placed over a Bunsen burner

Which is an example of concentration affecting the rate of reaction?

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

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

Which is an example of the chemical nature of substances affecting the rate of reaction? Select the correct answer below: 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

Which type of anion will typically result in an insoluble compound?

chromate

The relative numbers of reactants and products are represented by:

coefficients

If K is followed by a subscript c, that means it is evaluated using:

concentrations

Equilibrium is a ______________ process.

dynamic

As a reaction proceeds in the forward direction, K will:

increase

Which is an example of the state of subdivision of the reactants affecting the rate of reaction? Select the correct answer below: a reaction proceeds more quickly in the laboratory when placed over a Bunsen burner a reaction slows down as it proceeds calcium reacts with water moderately, sodium reacts with water explosively large pieces of iron react slowly with acids while finely divided iron reacts more rapidly

large pieces of iron react slowly with acids while finely divided iron reacts more rapidly

A catalyst lowers the activation energy of a reaction by:

providing an alternate pathway or mechanism

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

sodium oxidizes overnight whereas iron takes much longer

A catalyst will:

speed up a reaction

The coefficients in a balanced chemical equation are used to derive:

stoichiometric factors

Which is an example of the state of subdivision of the reactants affecting the rate of reaction? Select the correct answer below: the smaller the piece of wood, the faster it burns food spoils more quickly on the kitchen counter than in the fridge a reaction slows down as it proceeds calcium reacts with water moderately, sodium reacts with water explosively

the smaller the piece of wood, the faster it burns

The structure in a reaction that has the highest potential energy is the: Select the correct answer below: reactant product transition state depends on the reaction

transition state