Chem1

Front 1

(T/F) A catalyst acts by increasing the rate of the forward reaction more than the reverse reaction.

Back 1

False; Lowering of activation energy must be by the same numerical value in either direction (forward to reverse rate; ie. equilibrium constant) unchanged.

Front 2

(T/F) A catalyst may have molecular weight as low as 1 or higher than 200,000.

Back 2

True; Acid-catalyzed reactions are enhanced by the presence of protons, H+, which have a 'molecular' weight of 1, while enzymes, which catalyzez many biochemical reactions, are usually proteins of higher molecular weight, often in exces of 200,000.

Front 3

What is Hess's law?

Back 3

The total change in a thermodynamic state function (such as enthalpy here) can be found as the sum of the changes for a series of steps with the same net result.

Front 4

What is heat of fusion, delta(H_f)?

Back 4

delta(H_f) is defined as the enthalpy change accompanying the reaction, real or hypothetical of elements in their standard states coming together to form the product in question.

Front 5

What would you expect the energy of the formation of gaseous water from a liquid compared to the formation of liquid water?

Back 5

The formation of gaseous will be less exothermic than the formation of liquid water.

Front 6

Formation of water can be thought of as what?

Back 6

Combustion since H2 is reacting with O2 and therefore its exothermic.

Front 7

Cation radius is better/smaller than a neutral atom?

Back 7

Smaller b/c the removal of electrons decreases the electrostatic repulsion between remaining electrons, thereby allowing the nucleus to pull them closer, decreasing the ionic radius.

Front 8

Anion radius is bigger/smaller than a neutral atom?

Back 8

Bigger b/c of an increased number of electrons that repel one another.

Front 9

Pauli exclusion principle

Back 9

No two electrons on a single atom can have an identical set of
values for the four quantum numbers n, l, m_l, and m_s.

Front 10

Heisenberg uncertainty principle

Back 10

One cannot simultaneously determine the momentum and the location of an electron precisely.

Front 11

What is the volume of one mole of gas at STP?

Back 11

22.4 Liters

Front 12

What are characteristics of metals?

Back 12

physical properties: malleability, ductility, and luster

chemical properties: low ionization energy, electron affinity, and electronegativity.

Front 13

Metals are easily oxidized because...

Back 13

the low ionization energy of metals allows them to easily give up an electron to a willing acceptor; metals are therefore easily oxidized and thus make good reducing agents.

Front 14

What is dalton's law of partial pressures state?

Back 14

The pressure exerted by an ideal gas in a mixture is the same as it would be if the gas were to occupy the same volume alone.

Front 15

A 200mnL flask contains oxygen at 200mmHg and a 300mL flask contains neon at 100mmHg. The two flasks are then connected so that each gas fills their combined volumes. Assuming no change in temperature, what is the partial pressure of neon in the final mixture?

Back 15

Dalton's law of partial pressures states that the pressure exerted by an ideal gas in a mixture is the same as it would be if the gas were to occupy the same volume alone. If we focus on the neon we can approach this problem as if the volume increases from the initial 300 mL to the combined 500 mL and use the relationship P1V1 = P2V2 (Boyle's law). Note that, qualitatively, an increase in volume will lead to a decrease in pressure and so the answer must be less than 100 mmHg. Completing the calculations: P2 = P1V1/V2 = (100 mmHg)(300 mL)/(500 mL) = 3/5(100 mmHg) = 60 mmHg.

Front 16

In which of the following does inelastic collisions occur between molcules:
a. real gases
b. ideal gases
c. fusion reactions

Back 16

Inelastic collisions do occur in real gases and a nuclear fusion reaction is a reaction in which two nuclei collide to form a new, heavier nucleus.
Ideal gasses are elastic.

Front 17

Which are the assumpions of the Kinetic Theory of Gases?

Back 17

an ideal gas is composed of particles of:
negligible volume in constant but random motion,
that there are no interactions among these particles,
that any collisions are completely elastic, and that
the average kinetic energy of the particles is proportional to the absolute temperature.

Front 18

What hybridization does the central atom of the ion AB_6^-3 have (its octahedral geometry)?

Back 18

The hybridization of the central atom in a molecule or ion is easily determined by counting the number of bonds and electron pairs of the central atom and then counting orbitals, in s-p-d-f order. sp^3d^2.

Front 19

When would you see a sp^2d hybridization?

Back 19

sp^2d, is a much less common hybridization. It is found in molecules and ions such as ClO2-, where the central chlorine atom has two lone pairs and is bonded to the two oxygen atoms. This ion also has a dbl(?) bond which is formed via the side-by-side overlap of the third chlorine p orbital with one of the oxygen p orbitals. Since this chlorine p orbital is already in use, it is necessary for one of the chlorine 3d orbitals to participate in the hybridization.

Front 20

(T/F) Transition elements reside in the center, or d-block, of the Periodic Table and are often called transition metals because of their metallic character.

Back 20

True.

Front 21

(T/F) Most transition elements have incomplete d subshells, while the next s sublevel is occupied.

Back 21

True; for example, vanadium has the electron configuration V = [Ar]4s^2 3d^3 ; its 4s sublevel is occupied while its 3d subshell is incomplete.

Front 22

(T/F) Most transition elements have multiple oxidation states.

Back 22

True; for example, vanadium for example can lose the 4s electrons, the 3d electrons, or both to form a 2+, 3+ or 5+ cation respectively.

Front 23

(T/F) Transition metals include heavy metals.

Back 23

True; heavy metals such as gold and mercury are among their ranks.

Front 24

(T/F) Transition metals are located in each period of the periodic table.

Back 24

False; they are not found in the first two rows of the Periodic Table.

Front 25

Where are inert gases located on the periodic table?

Back 25

Inert gases, are the elements found in the last column of the table. aka. noble gases

Front 26

What are the characteristics of inert gases?

Back 26

Based on their position, one can predict that these elements will generally have:
* the smallest atomic radii
* the largest ionization energy
of the elements within a given period, or row, of the Periodic Table.

Front 27

Where are active metals found on periodic table and what are their characteristics?

Back 27

- elements found on the far left side of the table, particularly those in the lower left-hand corner
- These elements are relatively large in size, and have low ionization energies, electron affinities, and electronegativities.
- aptly named; they are so reactive that they are found in nature only in cationic form.

Front 28

Where are active non-metals found on periodic table and what are their characteristics?

Back 28

- active non-metals are found in the upper right-hand corner of the Periodic Table (but not in the last column)
- generally have large electron affinities and electronegativities.

Front 29

(T/F) Transition elements may have smaller atomic radii because electrons are added to the d orbitals of a lower principal quantum number.

Back 29

True.

Front 30

2 X(g) + Y(g) ==> Z(g)

If stoichiometric quantities of X(g) and Y(g) are introduced into a sealed, rigid container at constant temperature with an initial pressure of 12 atmospheres, what will the pressure in the container be when the reaction is complete?

Back 30

4 atmospheres; PV=nRT see that pressure is prop to moles.

Front 31

2 X(g) + Y(g) ==> Z(g)

If stoichiometric quantities of X(g) and Y(g) are placed in a sealed, flexible container with an initial volume volume of 30 liters at STP, what volume of Z(g) will be produced?

Back 31

10 liters; PV=nRT see that volume is prop to moles.

Front 32

What does a flexible container signify?

Back 32

pressure is constant.

Front 33

What does a rigid container signify?

Back 33

Pressure will change.

Front 34

How would you go about solving the following problem: What is the empirical formula of a compound which on analysis is shown to consist of 12.5% hydrogen, 37.5% carbon, and 50% oxygen by mass?

Back 34

Assume 100g sample and divide each by its atomic mass.

Front 35

(T/F) Group IA active metals can form only cations with a +1 oxdation # when reacted w/ halogens, alcohols or water.

Back 35

True.
Group IA active metals react with elemental oxygen, for example to form oxides of the general formula M2O, and these oxides can then react with water to form hydroxides of the general formula MOH.

Front 36

What is the general order of increase entropy?

Back 36

solid < liquid < ions in solution < gas.

Front 37

Does precipitation increase or decrease entropy?

Back 37

Precipitation takes aqueous ions to ionic solid and thus represents a decrease in entropy.

Front 38

Does neutralization increase or decrease entropy?

Back 38

Neutralization takes aqueous ions to molecules of liquid and is
accompanied by a net decrease in disorder.

Front 39

Which is has a larger radius: Cl- or K+?

Back 39

Cl- because anions have an increased # of electrons which causes repulsion.