Chem Lab Review

Give the number of nonbonding lone pairs electrons in H2NOH

• 0

• 1

• 2

• 3

• 4

The compound methyl amine, CH3NH2, contains a C-N bond. In this bond, which of the following best describes the change on the nitrogen atom ?

• slightly positive

• -1

• +1

• unchanged

• slightly negative

Which of the compounds below have bonds that are predominantly ionic?

• NH3

• KCl

• CF4

• both a and B

• both b and c

What type of bonding is most important in CH3CH2CH2CH2CH2CH3?

• covalent

• ionic

• hydrogen

• polar

Which of the following contains polar covalent bonds ?

• NH2

• Na2O

• KF

• H2

• both a and c

Which of the following covalent bonds has the largest dipole moment ?

• H-N

• C-O

• H-F

• C-C

• C-H

Which of the following elements does this electronic configuration represent 1s2 2s2 2p5?

• C

• Al

• N

• F

• O

which of the following is the most likely electronic structure for C2H2 ?

• 

• H-C-C-H

Which of the following structures, including formal charges, is correct for diazomethane, CH2N2?

How many unpaired electrons are present in the isolated carbon atom (atomic number =6) ?

• none

• one

• two

• three

• four

Give the formal charge on nitrogen in NH4.

• -2

• -1

• 0

• +1

• +2

Which of the following is the electronic configuration of the element Fe?

• 1s2 2s2 2p6 3s2 3p6 4s2 4d6

• 1s2 2s2 2p6 3s2 3p8 3d6

• 1s2 2s2 2p6 3s2 3p6 4s2 3d6

• 1s2 2s2 2p8 3s2 3p6 4s2 3d6

The atomic number of boron is 5. The correct electronic configuration of boron is

• 2s2 2p3

• 1s2 2s3

• 1s2 2p3

• 1s2 2s2 2p1

• 1s2 2s2 3s1

Give the electronic configuration of N-3

• 1s2 2s2 2p6

• 1s2 2s2 2p3

• 1s2 2s2

• 1s2 2s2 2p6 3s1

• 1s2 2s2 2p4

Which of the following is not a conjugate acid-base pair?

• H2SO4-, H2SO4

• H2O, HO-

• -OH, O2-

• H2O, H3O+

• NO3-, NO2-

Which of the following is the strongest acid ?

• CH3NH3+

• CH3NH2

• CH3OH

• CH3OH2+

• H2N-

The pKa of CH3COOH is a 4.8 and the pKa of HCOOH is 3.8. Given the information, one knows that

• CH3COOH completely ionizes in water

• CH3COOH reacts with HO- while HCOOH does not

• HCOOH is a weaker acid than CH2COOH

• HCOOH reacts with HO- CH3COOH does not

• HCOO- is a weaker base than CH3COO-

Identify the compound with the highest pKa

• CH3NH2

• CH3NH3+

• CH3OH

• CH3COOH

• H2O

Identify the compound with the highest pKa

• HCCN

• CH3NH2

• CH2CH2

• CH3CH3

• CH3OH

When a small amount of hexanoic acid [CH3(CH2)4CO2H, pka -4.8], is added to a separator funnel which contains the organic solvent diethyl ether and water with a pH of 2.0, it is found mainly in the ____ phase as ______.

• ether; CH3(CH2)4CO2H

• water; CH3(CH2)4CO2-

• ether; CH3(CH2)4CO2-

• water; CH3(CH2)4CO2H

• none of the above

When a small amount of hexanoic acid [CH3(CH2)4CO2H, pka -4.8], is added to a separate funnel which contains the organic solvent diethyl ether and water with a pH of 12.0, it is found mainly in the ____ phase as ______.

• water; CH3(CH2)4CO2-

• water; CH3(CH2)4CO2H

• ether; CH3(CH2)4CO2-

• ether; CH3(CH2)4CO2H

• none of the above

The conjugate acid of H2O is

• H3O+

• HO-

• H2O+

• H3O-

• H3O

H-A is an acid with a pka of 4.5. Which of the following statements about an aqueous solution of H-A is true?

• at pH= 5.5, the solution contains about 90% A- and 10% H-A.

• At pH= 3.5, the solution contains about 90% A- and 10% H-A

• At pH= 6.5, the solution contains about 80% A- and 20% H-A.

• at pH=4.5, the solution contains much more A- than H-A.

• at pH= 4.5, the solution contains much more H-A than A-.

Which of the following ions is the strongest acid?

• H30+

• HSO4-

• HO-

• H-

• H2)

Which of the following species cannot function as a lewis Acid ?

• H2O

• TiCl4

• AlCl3

• NH4+

• H+

What is the conjugate acid of NH3 ?

• +NH4

• -NH

• -NH2

• +NH2

• +NH3

What is the conjugate acid of CH3NH2?

• CH3NH-

• CH3NH3+

• NH4+

• NH2-

What is the conjugate base of CH3NH2?

• NH4+

• CH3NH-

• NH2-

• CH3NH3+

Ar there any conditions under which a student may work alone ?

• maybe

• yes

• no

• students may work unrestricted at their convenience

In case of an emergency in the lab, who should be notified ?

• instructor

• anybody

• SOuthern University Police

• a friend

What precautions are needed with long hair and breads?

• must be shampooed

• keep long hair tied back/ keep hair away from flames

• no precautions are necessary

• no long hair and/ or beards allowed in laboratory

What should be the very last function performed in the laboratory before you leave?

• make sure that your locker is secure

• wash your hands

• bid the instructor farewell

• arrange a time with you laboratory partner for lunch

What should be worn in a laboratory at all times?

• contact lenses

• mask

• a cap

• safety glasses

When adding a solid metal to water, the metal will:

• dissolve

• displace its volume

• lower the liquid volume

• form a homogenous mixture

Why is smoking not permitted in the lab ?

• it is bad for your health

• the laboratory could be blown up

• it is inconvenient

• there are no ash trays in the lab