reading quiz exam 2

During dilution process, __ does not change. a. volume of solution b. concentration of solution c. molarity of solution d. amount of solute

d. amount of solute

What is the correct name for CrCl3? a. chromium(III) chloride d. chromium(VI) chloride b. chromium trichloride e. chromium chloride c. chromium(VI) trichloride

a. chromium(III) chloride

sp orbitals have ___ shape. a. linear b. trigonal c. tetrahedral d. spherical

a. linear

Sigma bond is formed when ___ orbitals overlap. a. s and s b. s and p c. p and p d. all of above

d. all of the above

paramagnetism: a. attraction to magnetic field b. due to unpaired electrons c. opposite of diamagnetic d. all of above

d. all of the above

Which property below is typically used to predict the type of bond that forms between two elements? a. electronegativity d. electron affinity b. ionization energy e. atomic mass c. atomic radius

a. electronegativity

Which information below is NOT shown in Lewis structures of molecules? a. how atoms are arranged in space b. the number of bonding pairs of electrons between atoms c. nonbonding electrons on atoms d. the number of valence electrons in the molecule

a. how atoms are arranged in space

For a molecule with 2 e- in sigma, 2 e- in sigma-star, 4 e- in pi, and 1e- in pi-star orbitals have a bond order of __. Note: bond order = 1/2 {# bonding e- - #antibonding e-} a. 1/2{6-3} =3/2 b. 1/2{2-2}=0 c. 1/2{4-2}=1 d. 1/2{4-1}=3/2

a. 1/2{6-3} =3/2

sp2 orbitals consist of __ and in a shape of ___. a. 3 equivalent orbitals; trigonal planar b. 2 equivalent orbitals; linear c. 3 equivalent orbitals; bent d. 2 equivalent orbitals; trigonal planar

a. 3 equivalent orbitals; trigonal planar

If 50.0 g of seawater contains 2 g of NaCl, what is the percent by mass of NaCl? a. 4% b. 25% c. 100% d. 0.04%

a. 4%

Metallic chromium can be obtained from the mineral chromite (FeCr2O4). What is the mass percent of chromium in chromite? a. 46.46% d. 30.26% b. 61.90% e. 41.99% c. 23.23%

a. 46.46%

Which ion cannot be considered to have eight valence electrons? a. Li+ d. F- b. Mg2+ e. O2- c. N3-

a. Li+

In O-H bond, ___. a. O atom carry partial negative charge because it has higher E.N. value, attracting shared electrons more. b. O atom carry partial positive charge because it has higher E.N. value, attracting shared electrons more.

a. O atom carry partial negative charge because it has higher E.N. value, attracting shared electrons more.

A compound known to contain platinum, nitrogen, and hydrogen was analyzed and found to contain 74.1% Pt and 21.3% N; the remainder was hydrogen. What is the empirical formula for the compound? a. Pt(NH3)4 d. Pt(NH4)2 b. Pt(NH3)3 e. Pt(NH3)6 c. Pt2(NH3)2

a. Pt(NH3)4

According to valence bond theory, atoms share electrons when ___ overlap. a. atomic orbitals b. nuclei c. any electrons d. bond

a. atomic orbitals

Vector shown in fig 4.26 __. (select FALSE) a. represent bond angle b. represent dipole moment c. reflects differences of electronegativity between two atoms d. indicates partial positive atom with small plus sign

a. represent bond angle

Which type of molecular orbital is used to describe a buildup of electron density along the axis connecting two atomic nuclei to form a bonding orbital? a. sigma b. sigma star c. pi d. pi star

a. sigma

When bond order is 0, stable bond does not form between 2 atoms. a. true b. false

a. true

If there are 0.505 g of NaCl (58.44 g/mol) left in a beaker that originally contained 75.0 mL of saltwater, what must have been the concentration of the original solution? a. 0.00647 M d. 0.115 M b. 0.0115 M e. 0.673 M c. 0.0673 M Group of answer choices

b. 0.115 M

Select the highest concentration a. 10ppb b. 0.1ppm c. 0.00000000001%

b. 0.1ppm

When 20ml of ethanol is mixed with 30ml of water, what is the %vol of ethanol in solution? a. 15% b. 40% c. 60% d. 66%

b. 40%

What volume of 2.50 M NaOH (40.00 g/mol) contains 0.100 mole of NaOH? a. 0.250 L d. 0.250 mL b. 40.0 mL e. 0.0400 mL c. 25.0 mL

b. 40.0 mL

Following steps shown in Example 4.6 (pg218), draw Lewis structure of NF3. How many shared electrons are there in the Lewis structure of NF3? a. 3 d. 8 b. 6 e. 10 c. 4

b. 6

Caffeine has an elemental analysis of 49.48% C, 5.190% H, 16.47% O, and 28.85% N. It has a molar mass of 194.19 g/mol. What is the molecular formula of caffeine? a. C4H5N2O d. C6H6NO2 b. C8H10N4O2 e. C5H7NO c. C10H14N2O2

b. C8H10N4O2

Double bonds consist of __. a. two sigma bonds b. one sigma and one pi bonds c. two pi bonds

b. one sigma and one pi bond

What is the correct name of H2SO3? a. sulfuric acid d. dihydrogen sulfurtrioxide acid b. sulfurous acid e. hydrosulfurous acid c. hydrosulfuric acid

b. sulfurous acid

Atoms such as P and S can share more than 4 pairs of electrons (thus not following octet rule) because___. a. they have more s orbitals b. they have s, p and d orbitals in valence shell

b. they have s, p and d orbitals in valence shell

one s and one p orbitals are hybridized to produce __ hybrid orbital(s). a. one sp b. two sp c. one sp2 d. one sp3

b. two sp

Which statement below regarding Lewis dot symbols, Lewis structures, and the octet rule is FALSE? a. Atoms tend to gain, lose, or share electrons in order to attain eight valence electrons. b. There are some atoms that do not obey the octet rule. c. A molecule cannot have an odd number of valence electrons. d. Lewis dot structures can be written for atoms and for ions.

c. A molecule cannot have an odd number of valence electrons.

Which statement below regarding covalent bonds is FALSE? a. Electrons in a single covalent bond are mutually attracted to two nuclei. b. The average bond length is the distance between the nuclei when the energy is at a minimum. c. The energy of the interaction between two neutral atoms continuously decreases as their separation decreases. d. The covalently bonded atoms are at a lower energy than the separated atoms. e. Electron-nucleus attractions must overcome electron-electron and nucleus-nucleus repulsions.

c. The energy of the interaction between two neutral atoms continuously decreases as their separation decreases.

Resonance structures indicate that ________ a. there is more than one allotropic form of a compound. b. more than one ionic form of a compound exists. c. a molecule's electronic structure is an average of all possible Lewis structures. d. more than one isotopic form of an element exists in the molecule. e. the molecule jumps back and forth between two or more different electronic structures.

c. a molecule's electronic structure is an average of all possible Lewis structures.

Based on figure 4.6 and 8, O-H bond has differences of electronegativity ___. Therefore O-H bond is a ___ bond. a. 1.4 ; non polar covalent b. 3.5; polar covalent c. 1.4; polar colavent d. 2.1; polar covalent

c. 1.4; polar colavent

Hydrogen can have at most ________ electrons in its valence shell. a. 0 d. 4 b. 1 e. 8 c. 2

c. 2

How many valence electrons does arsenic have? a. 1 d. 15 b. 3 e. 33 c. 5

c. 5

How many grams of solid potassium chlorate (KClO3, 122.55 g/mol) are needed to make 150 mL of 0.50 M solution? a. 0.11 g d. 0.41 g b. 37 g c. 9.2 g

c. 9.2 g

Two inorganic blue pigments are Han blue (BaCuSi4O10) and Egyptian blue (CaCuSi4O10). Which has a higher molar mass and by how much? a. Egyptian blue by 137.3 g/mol d. Han blue by 137.3 g/mol b. Egyptian blue by 40.08 g/mol e. Han blue by 177.4 g/mol c. Han blue by 97.22 g/mol

c. Han blue by 97.22 g/mol

VSEPR theory cannot alone explain behavior/concept such as a. different magnetic behavior of similar molecules b. how to reconcile geometry of atomic orbitals with molecular shapes c. all of above

c. all of the above

For the VSEPR model, repulsion of ___ are considered. (FALSE) a. bonding electrons of a central atom b. lone pairs of a central atom c. core electrons

c. core electrons

In VSEPR theory, molecular geometry is determined by ________ a. electron-proton attractive forces. d. proton-proton repulsive forces. b. electron-electron attractive forces. e. electron-nucleus attractive forces. c. electron-electron repulsive forces.

c. electron-electron repulsive forces.

Features of hybridizations: select false a. shapes, orientations and energy level of hybrid orbitals are different from those of orbitals of parent atoms b. hybrid orbitals are generated by combining atomic orbitals c. hybrid orbitals overlap to form pi bond d. all orbitals in a set of hybrid orbitals are equivalent in shape and energy

c. hybrid orbitals overlap to form pi bond

For a molecule to be polar, __. (select FALSE) a. it must contain at least one polar bond b. vector of dipole moment of each bond does not cancel c. it cannot be a linear shape

c. it cannot be a linear shape

sp3 orbitals has __ shape. a. linear b. trigonal c. tetrahedral d. spherical

c. tetrahedral

The geometry of molecules with 4 regions of high electron density is __. a. linear b. trigonal planar c. tetrahedral, bent or trigonal pyramid d. octahedral

c. tetrahedral, bent or trigonal pyramid

Aqua regia is a mixture of hydrochloric acid and nitric acid that is capable of dissolving gold. What are the formulas of these acids? a. HClO, HNO4 d. HCl, HNO3 b. HClO4, HNO3 e. HCl, HNO c. HCl, HNO2

d. HCl, HNO3

Which compound below is molecular (covalent)? Note: metal and non-metal form ionic bond while non-metal and non-metal form covalent bond. a. CuS d. SF4 b. K2S e. AlCl3 c. BaF2

d. SF4

A covalent bond results when ________ a. electrons are transferred from one atom to another atom. b. atoms pool their electrons to form a "sea" of electrons. c. atoms have outer electrons with the same principal quantum number. d. electrons are shared between a pair of atoms. e. an atom has eight valence electrons.

d. electrons are shared between a pair of atoms.

When forming a double bond, __ total number of electrons are shared between a pair of atoms. a. 1 b. 2 c. 3 d. 4

d. 4

Commercial hydrochloric acid is 12.1 M. What volume of commercial HCl solution should be used to prepare 250.0 mL of 3.00 M HCl? a. 139 mL d. 62.0 mL b. 126 mL e. 83.0 mL c. 252 mL

d. 62.0 mL

Look at the structure of BrCl3 in example 4.7 (pg 223). # valence shell e- in free Br atom is __; # lone pair electron on Br is __; 1/2 of # bonding e- is __. The formal charge of Br therefore is ___. a. 7, 4,6 , -3 b. 7,2, 6, -1 c. 6, 2,3, 1 d. 7, 4, 3, 0

d. 7, 4, 3, 0

An iron ore, magnetite, contains only iron and oxygen. In refining 100.0 g of the ore, 72.35 g of iron are obtained. What is the empirical formula of the ore? a. Fe2O3 d. Fe3O4 b. FeO2 e. FeO c. Fe2O5

d. Fe3O4

Which statement below is FALSE? a. Molecular orbitals may be higher or lower in energy than the atomic orbitals from which they are formed. b. Molecular orbitals belong to all of the atoms in a molecule. c. Molecular orbitals are mathematical combinations of atomic orbitals. d. The energies associated with molecular orbitals are no longer quantized.

d. The energies associated with molecular orbitals are no longer quantized.

For bond formation, __ is/are crucial. a. atomic distance b. shape of orbitald c. orientation of orbitals to allow greater overlap d. atomic distance AND orientation of orbitals to allow greater overlap

d. atomic distance AND orientation of orbitals to allow greater overlap

Shape of H2O molecule (first draw Lewis structure) according to VSEPR is __. a. linear b. trigonal planar c. trigonal pyramid d. bent

d. bent

sigma orbitals are ___. Select FALSE. a. formed by in-phase combination of orbitals b. lower energy than sigma star c. bonding orbitals d. form pi bonds

d. form pi bonds

Formal charge is___ .(select false) a. (#valence e-) - (#lone pair e-)-1/2 (#bonding electrons) b. hypothetical charge of an atom if bonding electrons are evenly distributed c. often different from total charge of a molecule d. hypothetical charge of molecule

d. hypothetical charge of molecule

What does MO theory explain that other bonding theories do not? a. bonding patterns of atoms b. bonding capacity of atoms c. molecular shape and polarity d. molecular magnetic and optical properties e. bond angles

d. molecular magnetic and optical properties

Molarity, M, is defined as a. moles of solute dissolved in 1 mol of solvent. b. moles of solute dissolved in 1 kg of solvent. c. moles of solute dissolved in 1 L of solvent. d. moles of solute dissolved in 1 L of solution. e. moles of solute dissolved in the solution.

d. moles of solute dissolved in 1 L of solution.

pi bonds are formed by ___. a. overlap of sp2 orbitals b. overlap of sp orbitald c. overlap of sp3 orbitald d. side-by-side overlap of unhybridized p-orbitals of two atoms

d. side-by-side overlap of unhybridized p-orbitals of two atoms

What is the hybridization of carbon in C2H2? a. sp2 d. sp b. sp3 e. sp3d 2 c. sp3d

d. sp

Shape of a molecule with 4 total electron pairs with 1 lone pair is __. a. trigonal planar b. bent c. tetrahedral d. trigonal pyramid

d. trigonal pyramid

Which statement below regarding bond polarity is FALSE? a. Electrons are shared fairly equally in nonpolar bonds. b. Electrons are shared unequally in polar bonds. c. Polar bonds possess a small electric dipole. d. Atoms sharing electrons in nonpolar bonds do not have partial charges. e. Electrons in polar bonds are transferred from one atom to another.

e. Electrons in polar bonds are transferred from one atom to another.