10-10-10

Given the following thermochemical data: N₂O₄(g)→2NO₂(g) ∆H=+57.93 kJ 2NO(g)+O₂(g)→2NO₂(g) ∆H=-113.14kJ determine the heat f the reaction 2NO(g)+O₂(g)→N₂O₄(g)

-171.07kJ -57.93+-113.14=-171.07

Reaction 1: N₂H(l)+H₂(g)→2NH₃(g) ∆H=? Reaction 2: N₂H(l)+CH₄O(l)→CH₂O(g)+N₂(g)+3H₂(g) ∆H=-37kJ/mol Reaction 3: N₂(g)+3H₂(g)→2NH₃(g) ∆H=-46kJ/mol Reaction 4: CH₄O(l)→CH₂O(g)+H₂(g) ∆H=-65kJ/mol What is the enthalpy change for reaction 1?

-18kJ/mol

Propane gas, C₃H₈(g) burns according to the equation below C₃H₈(g)+5O₂(g)→3CO₂(g)+H₂O(g) A mixture containing .03 moles of C₃H₈(g) and .2 moles of O₂ (g) is placed in a rigid container and its pressure is measured. The mixture is ignited. Which describes the contents of the container after maximum reaction has occurred and the system returned to its original temperature? a.).050 mol O₂(g) remains unreacted and the pressure has increased b.).050 mol O₂(g) remains unreacted and the pressure has decreased c.).170 mol O₂(g) remains unreacted and the pressure has decreased d.).020 mol C₃H₈(g) remains unreacted and the pressure has decreased

.050 mol O₂(g) remains unreacted and the pressure has increased 6 moles of gas→7 moles of gas

A mixture containing .60 mol Al in contact with .75 mol of Cl₂ is ignited in a closed container. Assuming complete reaction, which gives the maximum quantity of AlCl₃ produced and the corresponding quantity of unconsumed reactant? 2Al(s)+3Cl₂(g)→2AlCl³(s)

.5 mol AlCl₃ and .1 mol Al unreacted

A gaseous mixture containing 7 moles of nitrogen, 2.5 moles of oxygen and .5 moles of helium exerts a total pressure of .90 atmosphere. What is the partial pressure of the nitrogen?

.63 atm

A 40 mL sample of .25M KOH is added to 60 mL of .15 M Ba(OH)₂. What is the molar concentration of OH⁻(aq) in the resulting solutions? (Assume that the volumes are additive)

0.28 M

The temperature of a sample of a ideal gas confined in a 2.0L container was raised from 27C to 77C. IF the initial pressure of the gas was 1200 mmHg what was the final pressure of the gas?

1,400mmHg Ideal gas: high temp w/ low pressure Ideal gas law: PV=nRT

The weak acid H₂A ionizes in two steps with these equilibrium constants: H₂A⇌H⁺+HA⁻ Ka₁=2.3*10⁻⁴ HA-⇌H⁺+A²⁻ Ka₂=4.5*10⁻⁷ What is the equilibrium constant for the reaction: H₂A⇌2H⁺+A²⁻

1.0*10⁻¹⁰

What is the bond order for the C-O bond in carbonate, CO₃²⁻

1.3 4/3=1.3

A first-order reaction has a half-life of 36s. What is the value of the rate constant?

1.9*10⁻²s⁻¹

A first-order reaction had a half life of 85s. What fraction of the reaction is left after 255s?

1/8

...C₁₀H₁₂O₄S(s)+...O₂(g)→...CO₂(g)+...SO₂(g)+...H₂O(g) when the equation above is balanced and all the coefficient are reduced to their lowest whole-number terms, the coefficient for O₂ is?

12

Reaction 1: N₂H(l)+H₂(g)→2NH₃(g) ∆H=? Reaction 2: N₂H(l)+CH₄O(l)→CH₂O(g)+N₂(g)+3H₂(g) ∆H=-37kJ/mol Reaction 3: N₂(g)+3H₂(g)→2NH₃(g) ∆H=-46kJ/mol Reaction 4: CH₄O(l)→CH₂O(g)+H₂(g) ∆H=-65kJ/mol If 64g of CH₄O were to decompose via reaction 4, approximately how much energy would be released or absorbed?

130kJ of energy will be absorbed 2mol=-65*2=-130

The rate at which CO₂(g) is produced is the following reaction: 2C₆H₆(g)+15O₂(g)→12CO₂(g)+6H₂O(l) is 2.2*10⁻² mol L*⁻1s⁻1. What is the rate at which O₂ is consumed?

2.8*10⁻²mol L*⁻1s⁻1 4:5 4(.05/1.02) .05*5=.025

If a reactant's concentration is doubled and the react rate increases by a factor of 8, the exponent for that reactant in the rate law should be

3 2^x=8 x=3

What is the weight of NaNO₃ (molecular weight 85.0) present in 100 mL of a 4.00 molar solution?

34.0 grams

When the eqution for the following reaction is balanced, the lowest whole-number coefficient for H₂O will be: _Be₂C+_H₂O→_Be(OH)₂+_CH₄

4

14H⁺(aq)+Cr₂O₇²⁻(aq)+3Ni(s)→2Cr³⁺(aq)+3Ni²⁺(aq)+7H₂O(l) In the above reaction, a piece of solid nickel is added to a solution of potassium dichromate. How many moles of electrons are transferred when 1 mole of potassium dichromate is mixed with 3 mole of nickel

6 moles electrons

_Cr₂O₇²⁻+_e⁻+_H⁺→_Cr³⁺+_H₂O(l) When the equation for the half reaction above is balanced with the lowest whole-number coefficients, the coefficient for H₂O is

7

For the following reaction: heat+2NO₂(g)⇌N₂O₄(g) Which will NOT be effective in increasing the amount of N₂O₄(g)? a.) Decreasing the volume of the reaction vessel b.) Increasing the temperature c.) Adding a catalyst to the reaction vessel d.) Removing the N₂O₄ with a solid absorbent

Adding a catalyst to the reaction vessel Catalyst will not change "K" value", it just make the reactions faster

Which of the following has the smallest ionic radius? Al³⁺, F⁻,Mg²⁺, Na⁺

Al³⁺

Which of the following compounds will NOT form hydrogen-bonds? CH₂F₂ CH₃OH H₂NCH₂CH₂CH₃ HOCH₂CH₂OH

CH₂F₂

Which of the following compounds is incorrectly classified? a.) NaF is an electrolyte b.)CH₃OH is a weak electrolyte c.) Mg(C₂H₃O₂) is an electrolyte d.) CH₃CH₂COOH is a weak electrolyte

CH₃OH is a weak electrolyte

A 22.og sample of a unknown gas occupies 11.2L at STP. Which of the following could be the identity of the gas? CO₂, SO₃, O₂, He

CO₂ PV=nrt (1)11.2=n22.4

In which of the following molecules does a hydrogen have a oxidation state of -1? a.)H₂O b.)NH₃ c.)CaH₂ d,)H₂

CaH₂

In which of the following compounds is the mass ratio of chromium to oxygen closest to 1.6 to 1.0? CrO₃, CrO₂, CrO, Cr₂O,Cr₂O₃

CrO₂ 56:32, 56 is amost double of 32

Which of the following is most soluble in hexane? a.) KCl b.) C₂H₅OH c.) C₆H₆ d.) H₂O

C₆H₆

Which element is expected to have the greatest polarizability? a.) Fe b.) Ca c.)Ne d.) S

Fe

Consider the three acids: HF, HSO₄⁻ and H₂PO₄⁻. Which list includes only the conjugate bases of the acids given above? OH⁻,SO₄²⁻ and PO₄³⁻ F⁻, SO₄²⁻ and HPO₄²⁻ H₂F⁺, H₂SO₄, H₃PO₄ F⁻,SO₄²⁻,PO₄³⁻

F⁻, SO₄²⁻ and HPO₄²⁻

Identify the net ionic equation for the reaction of Acetic acid and sodium hydroxide

HC₂H₃O₃+OH⁻→C₂H₃O₂⁻+H₂O

Which of the following lists of species is in order of increasing boiling points? H₂, N₂, NH₃ N₂, NH₃, H₂ NH₃,H₂,N₂ NH₃, N₂, H₂

H₂, N₂, NH₃

Which could account for a change in the distance between molecules is a sample of gas? I. increase in density at constant temperature II. increase in temperature at constant pressure III. increase in temperature at constant volume a.) I b.) II c.) I and II d.) I and III e.) I, II and III

I and II

How does the pH of the solution change as the reaction progresses? a.) It increases but the solutions remains basic b.) It increases but the solutions remains acidic c.) It decreases but the solutions remains basic d.) It decreases but the solutions remains acidic

It increases but the solutions remains acidic

Reaction 1: N₂H(l)+H₂(g)→2NH₃(g) ∆H=? Reaction 2: N₂H(l)+CH₄O(l)→CH₂O(g)+N₂(g)+3H₂(g) ∆H=-37kJ/mol Reaction 3: N₂(g)+3H₂(g)→2NH₃(g) ∆H=-46kJ/mol Reaction 4: CH₄O(l)→CH₂O(g)+H₂(g) ∆H=-65kJ/mol Under what conditions would reaction 3 be spontaneous?

It is only favored at low temperatures

The rate Law for a reacion is found ro be rate=k[A]²[B]. Which of the following is true about this system? a.) A plot of the log rate vs time is a stright line b.) The units for the rate constant are mol²L⁻²S⁻² c.)The reaction is unlikely since it implies that simultaneous collisions of the two atoms of A and one of B d.)It is unlikely that the first step of the mechanism is the rate-limiting step

It is unlikely that the first step of the mechanism is the rate-limiting step

The value of Ka for HSO₄⁻ is 1*10⁻². What is the value of Kb for So₄⁻²?

Kb=1*10⁻¹²

14H⁺(aq)+Cr₂O₇²⁻(aq)+3Ni(s)→2Cr³⁺(aq)+3Ni²⁺(aq)+7H₂O(l) In the above reaction, a piece of solid nickel is added to a solution of potassium dichromate. Which species is being oxidized and which species is being reduced?

Oxidized:Ni Reduced:Cr₂O₇²⁻

Which of the following has a zero dipole moment? a.) NH₃ b.) PF₅ c.) SO₂ d.) NO₂

PF₅

What is the net ionic equation for the following reaction to takes place in a AQUEOUS solution? CrCl₃+Pb(NO₃)₂⁺→PbCl₂+Cr(NO₃)²

Pb²⁺(aq)+2Cl⁻(aq)→PbCl₂(s)

Step 1) NO₂+O₃→NO₃+O₂ (slow) Step 2) NO₃+NO₂→N₂O₅ (fast) The proposed reaction mechanism for the reaction of nitrogen dioxide and ozone is detailed above. What is the rate law for the reaction?

Rate=k[NO₂][O₃]

Which of the following is polar? SF₄, XeF₄, BF₃, SbF₅

SF₄

Which of these molecules has the most pi bonds? HCN PF₅ NH₃ SO₃

SO₃

A compound is made up entirely of silicon and oxygen atoms. If there is 14g of silicon and 32g of oxygen present, what is the empirical formula of the compound?

SiO₄ 14g= 1/2 Si 32g= 2O 1/2:2=1:4

X=CH₃-CH₂-CH₂-CH₂-CH₃ Y=CH₃-CH₂-CH₂-CH₂-OH Z=OH-CH₂-CH₂-CH₂-OH Based on concepts of polarity and hydrogen bonding, which of the following sequences correctly lists the compounds above in the order of their increasing solubility in water?

X<Y<Z

Identify the reaction in which Kc is equal to Kp a.) H₂(g)+S(s)⇌H₂S(g) b.)H₂O(g)⇌2H₂(g)+O₂(s) c.)H₂(g)+Br(l)⇌2HBr(g) d.)2NO₂(g)⇌N₂O₄(g)

a.) H₂(g)+S(s)⇌H₂S(g) moles of reactant gas=moles of product gas

An unknown substance is found to have a high melting point. In addition, it is a poor conductor of electricity and does not dissolve in water. The substance most likely contains

covalent network bonding

Reaction 1: N₂H(l)+H₂(g)→2NH₃(g) ∆H=? Reaction 2: N₂H(l)+CH₄O(l)→CH₂O(g)+N₂(g)+3H₂(g) ∆H=-37kJ/mol Reaction 3: N₂(g)+3H₂(g)→2NH₃(g) ∆H=-46kJ/mol Reaction 4: CH₄O(l)→CH₂O(g)+H₂(g) ∆H=-65kJ/mol Which of the following is true for all reactions a.) entropy increases b.) if completed in a sealed container, the pressure will decrease as the reactions go to compleation c.) the activation energy for all reactions will decrease with increasing temperature d.) more energy is released when the bonds in the products form than is necessary to break down the bonds in the reactants

d.) more energy is released when the bonds in the products form than is necessary to break down the bonds in the reactants because exothermic

Compared to water, a .2 M solution of NaCl will have all the following properties EXCEPT a.) greater density b.) lower vapor pressure c.) lower boiling point d.) grater conductivity

lower boiling point

A graph of the reciprocal of reactant concentration versus time will give a straight line for what order reactions

second order reaction

Which physical transformation occurs in the process called sublimation?

solid-gas

When Potassium Carbonate is dissolved in water a.) the soultion is acidic becasue of the hydrolysis of the CO₃²⁻ ion b.) the solution is basic because the hydrolysis of the CO₃²⁻ ion c.) the solution is basic because of the K⁺ ions d.) the solution is acidic because of the K⁺ ions

the solution is basic because the hydrolysis of the CO₃²⁻ ion

Which of the following nuclei had 3 more neutrons than protons? ¹¹B, ³⁷Cl, ²⁴Mg, ⁷⁰Ga, ¹⁹F

³⁷Cl

A certain reaction is non-spontaneous under standard conditions, but becomes spontaneous at lower temperature. What conculsion may be drawn under standard conditions? a.) ∆H>0,∆S<0,∆G>0 b.) ∆H<.0,∆S<0,∆G>0 c.) ∆H<0,∆S>0,∆G>0 d.) ∆H>0,∆S>0,∆G>0

∆H<0,∆S<0,∆G>0

All of the following are ture about a boliling liquid EXCEPT a.)∆G must be 0 b.)∆S must be positive c.)∆H must be positive d.)∆S must equal ∆H

∆S must equal ∆H