Chem Chapter Seven

The enthalpy for the formation of 1 mole of NH3(aq) is -80.29 kJ/mol. What is the deltaHf for the formation of 3moles of NH3(aq)?

-240.87 kJ

How much heat is absorbed during production of 143gNO by the combination of nitrogen and oxygen

102kcal

N2+O2----> 2NO deltaH= 43.2kcal. Based on the reaction shown, which statement is true?

43.2 kcal are consumed when 1.00 mole of O2 reacts

Consider this combination reaction: 2Mg(s)+O2(g)---> 2MgO(s) deltaH=-1204 kJ. What is the enthalpy decomposition of 1 mole of MgO(s) into Mg(s) and O2(g)?

602 kJ/mol

S+O2----> SO2 delta H= -70.8 kcal. Based on the reaction shown, which statement is true?

70.8kcal are consumed when 32.1g sulfur reacts

Consider the reaction shown: N2+O2--->2NO deltaH=43.2kcal. When 50.0g of N2 react, kcal will be

77.1; consumed

What is a catalyst

a chemical which enhances the reaction rate without undergoing a permanent change in the reaction; lowers energy barrier, Eact decreases, rate increases

For a chemical reaction to occur, all of the following must happen except

a large enough number of collisions must occur

What turns blue litmus paper red

acids

What do you disregard from the chemical equation when writing the K= formulas

all pure liquids and solids

what turns red litmus paper blue

bases

stage at which the rate of forward reaction is exactly equal to the rate of the reverse reaction

chemical equilibrium

In the reaction A+B--->AB, which of the following will NOT increase the rate?

decreasing the temperature

a process or reaction which takes in heat from the surroundings is said to be

endothermic

Consider the reaction shown: 452kcal+4PCl5(s)-----> P4(s)+10Cl2(g). We can say this reaction is ____ and that the sign of H is____.

endothermic;positive

When you increase the concentration of the prodcuts

eq. will shift to the left, reverse reaction will take place

When you increase the concentration of reactants

eq. will shift to the right, forward reaction will take place to reduce the concentration of the reactant

A reaction is said to be ____if the bonds formed during a reaction are stronger than the bonds broken.

exothermic

a process or reaction which releases heat to the surroundings is said to be

exothermic

Consider the reaction shown: C3H8+5O2--->3CO2+4H2O+488kcal. We can say this reaction is ______ and that the sign of H is_____.

exothermic; negative

Catalysts don't change the eq. concentration, but is equilibrium reached faster or slower

faster

When K>1 at equilibrium, the predominant species existing in the products, so which reaction is favored?

forward

a rapid reaction is distinguished by

having a small value of activation energy

HBr

hydrobromic acids

HCl

hydrochloric acid

HI

hydroiodic acid

When a gas reacts with a solid/liquid as the surface area of the solid or liquid reactant increases, the reaction rate

increases

When the concentration of the reactant is increased, the reaction rate

increases

When the temperature increases, the reaction rate

increases

Which factors would increase the rate of a reaction

increasing the temperature, removing products as they are formed,adding a catalyst

all of the statements regarding delta H are correct except

it can be called entropy change

Which statement best describes the way a catalyst works?

it decreases the value of Eact

What's a clue for remembering strong bases

look for OH

Which factors would decrease the rate of a reaction

lowering the temperature

HNO3

nitric acids

HClO4

perchloric acid

When writing a K= formula, which goes in the numerator, reactants or products?

products

A positive value for deltaH for a chemical reaction is an indication of which of the following?

products have high potential energy,and the reaction is endothermic

define dynamic equilibrium

rate of forward reaction equals rate of reverse reaction

Which of the following statements can be assumed to be true about how reactions occur?

reactant particles must collide with each other

When K<1, the predominant species existing at equilibrium are the what

reactants

H2SO4

sulfuric acid

Activation energy can best be described as

the difference in energy between reactants and the maximum energy

When HCl(aq) and NaOH(aq) are mixed in a beaker, the beaker feels warm to the touch. What is known about the enthalpy of this reaction?

the reaction is exothermic

Reaction rates are determined by all of the following factors except

the spontaneity of the reaction

Which of the following will affect all reaction rates

the temperature of the reactants, the presence of a catalyst, the concentrations of the reactants

Le Chatelier's principle

when stress is applied on a reaction at equilibrium by changing experimental conditions such as concentration, temperature, etc., the equilibrium will shift to lower the effects of changed parameter

do all concentrations remain constant at chemical equilibrium

yes