Chem 1010 CH 6-10
Which of the following molecules contains an ionic bond?
#11 Ch 6 MgCI2
Which of the following molecules is the most polar?
#4 ch 6 H-F
If a neutral atom loses one electron, what is the electrical charge of the atom?
+1
How many covalent bonds will the N atom usually form?
3
How many valence electrons does boron (B, atomic no. = 5) have?
3
If the concentration of gold in seawater is 2.0 milligram per ton of sea water and the mass of the ocean is 1.5 × 1018 tons, how much gold is in the ocean?
3.0 × 1012 kg
How many molecules of sucrose are in a 0.500 moles of sucrose?
3.01 × 1023 molecules of sucrose
How many substituents are on the carbon atom in CH_4?
4
How many substituents are on the nitrogen atom in NH4+?
4
How many substituents are on the nitrogen atom in NH_4+
4
What is the molarity when water is added to 2 moles of sodium chloride to make 0.5 liter of solution?
4 M Molarity=moles of solute/L of solution 2/0.5=4
How many oxygen molecules are needed to make 10 carbon dioxide molecules according to the following balanced chemical equation? 2 CO + O2 → 2 CO2
5
How many valence electrons does bromine (Br, atomic no. = 35) have?
7
Chlorine is a gas at room temperature, but bromine is a liquid. Explain.
Bromine atoms are larger and this makes the formation of induced dipole-induced dipole attractions more favorable.
Which of the following would have the lowest melting point? CCI4 CBr4 CF4 CI4
CF4
Which of the following might have the lowest solubility in water?
CH3CH3
How do the electron-dot structures of elements in the same group in the periodic table compare with one another?
Elements of the same group have the same number of valence electrons.
Which of the following statements is not in line with the concepts of thermodynamics
Energy has a tendency to stay in one place.
Which of the following has the greatest number of nonbonding pairs of electrons?
F
Which of the following molecules contains a polar covalent bond? H-F Ci-Ci H-H F-F
H-F
Which of the following molecules would contain a dipole?
H-F
Which of the following molecules would you expect to be the least attracted to a Na+ ion
H3C-CH3
What is the compound that forms if you react potassium and sulfur?
K2S
A student is told to use 10.00 grams of sodium chloride to make an aqueous solution that has a concentration of 1.00 grams of sodium chloride per liter of solution. How much water will she use in making this solution?
Slightly less than 10 L
A saturated solution of compound X in water has a greater concentration than does a saturated solution of compound Y. Does it follow that compound X is also more soluble in water?
Yes, compound X is more soluble than is compound Y because a greater concentration in water can be obtained.
The separation of charges within a polar molecule is called a(n) ________.
dipole
Classify the following bonds as ionic, covalent, or neither O with F; Ca with Cl; Na with Na
covalent, ionic, neither
The acronym VSEPR stands for ________.
valence shell electron {**pair repulsion}
Two liquids, A and B, have very different physical properties. A and B do not mix. A boils at 80°C and freezes at -30°C. B boils at 35°C and freezes at -100°C. Molecules of which are likely to have the largest dipole?
molecule A
What is the molecular shape of the ammonia molecule?
pyramidal
Which is greater: 1.01 amu of hydrogen or 1.01 grams of hydrogen? 1.01 grams of hydrogen and 1.01 amu of hydrogen have the same mass. 1.01 grams of hydrogen is greater than 1.01 amu of hydrogen 1.01 amu of hydrogen is greater than 1.01 grams of hydrogen.
1.01 grams of hydrogen is greater than 1.01 amu of hydrogen
How many electrons are used to draw the electron-dot structure for acetylene?
10
If you need 10. moles of sucrose, how many liters of a 4.0 molar solution would you need?
2.5L
If the solubility of a compound is 30 grams per liter, how much solid is left undissolved if you mix 30 g of the compound in 0.33 L of solution?
20g
Which of the following bonds would be the most polar? C-F C-Cl C-Br C-I
C-F
Which of the following bonds would be the least polar? C-F C-O C-Cl C-H
C-H
Germanium chloride has only two atoms surrounding the central germanium atom. Why then is the germanium chloride molecule bent?
A lone pair of electrons on germanium pushes it to this orientation.
Which of the following describes an aqueous solution?
A mixture of some compound dissolved in water
Water and methane have about the same mass. Why is the boiling point of water so much higher than that of methane?
All of the above
Which of the following statements about catalysts is NOT true? A catalyst alters the rate of a chemical reaction. A catalyst can be consumed in a reaction as long as it is regenerated. A catalyst can be used to speed up slow reactions. A catalyst does not change the energy of the reactants or the products.
All of the above
Which of the following elements will most likely not form an ion at all?
Ar
How is the solubility of a gas affected by temperature
As temperature goes down, the solubility goes up
How is the solubility of a gas affected by temperature?
As temperature goes down, the solubility goes up.
What would be the shape of a molecule where the central atom has two nonbonding pairs while also covalently bonded to two other atoms?
Bent
If carbonic acid (H2CO3) were to undergo ionization, what would one of the products be? H- CO2 CO3- Correct! CO32-
CO_32-
Which of the following compounds would be ionic?
CaCl2
Which of the following elements will most likely form an ion with a -1 charge?
Cl
What is a reaction rate?
It is the speed at which reactants are consumed or product is formed.
For the following balanced reaction, which of the following is a solid? 2 Na(l) + Cl2(g) → 2 NaCl(s) (I know Cl2 is a gas)
NaCl
Take enough money away from your bank account and the bank will show a negative credit. Take an electron away from an atom, however, and the atom shows up positive. Explain.
Neutral atoms contain identically charged but oppositely signed protons and electrons. Removing one of the negative electrons results in an excess of positively charged protons.
Which of the following statements describes a polar molecule? The molecules are usually not attracted to one another very strongly. Polar molecules have the weakest intermolecular interactions with ionic compounds. The molecules have a high degree of symmetry.
None of these statements describe polar molecules.
Phosphine is a covalent compound that contains phosphorus, P, and hydrogen, H. What is its chemical formula?
PH_3
The atomic masses appearing in the periodic table are ________.
Relative masses
Which of the following elements will most likely form an ion with a -2 charge? Na S Ne Mg
S
If you were to increase the pressure of a gas above a liquid (such as by pressing a piston above a liquid) what happens?
The gas is forced into solution and the solubility increases.
Why is the surface area of a gecko's foot so extensive?
The greater the surface area the greater the number of induced dipole-induced dipole forces of attraction that can occur between the gecko's foot and the surface.
Atoms of metallic elements can form ionic bonds, but they are not very good at forming covalent bonds. Why?
They have a great tendency to lose electrons.
How many moles of water are there in 100. grams of water?
add the atomic mass up then take 100/the total atomic mass which equals n (n is the number of moles) 1.0079+1.0079+15.9994=18.0152 100/18.0152=5.55 answer n=5.55
An atom loses an electron to another atom. Is this an example of a physical or chemical change?
chemical change involving the formation of ions
A hydrogen atom does not form more than one covalent bond because it ________.
has only one electron to share
The number of nonbonding (lone) electron pairs in the ammonia molecule is ________.
one
What is happening at the molecular level when a polar molecule like water interacts with a typical sodium ion?
the water molecule aligns such that the oxygen interacts with the sodium
What does the line in the following example actually represent? H—H
(A) a shared pair of electrons (B) a covalent bond Correct Answer (C) - Both A and B
If a neutral atom gains two electrons, what is the electrical charge of the atom?
-2
How many nonbonding pairs of electrons are in the following molecule? H—H
0
Which of the following solutions is the most concentrated? 0.5 L of a 3 molar solution 3.0 L of a 0.5 molar solution 2.0 L of a 1 molar solution 0.5 L of a 1 molar solution 2.0 L of a 2 molar solution
0.5 L of a 3 molar solution
Which of the following solutions is the most concentrated? 0.1 liter of water with 1 gram of sugar 2 liters of water with 0.2 gram of sugar 0.5 liter of water with 50 grams of sugar 3 liters of water with 30 grams of sugar
0.5 liter of water with 50 grams of sugar
How many moles of sugar, C12H22O11, are there in 200. grams?
0.585 moles
How many more electrons can fit within the valence shell of a hydrogen atom?
1
What is the molarity of 0.50 liters of a solution with five moles of sucrose in it?
10. molar
How many electrons are used to draw the electron-dot structure for hydrogen peroxide?
14 (H2O2
How many electrons are used to draw the electron-dot structure for calcium chloride?
16
Which covalent bond is more polar: a sulfur-bromine (S-Br) bond or a selenium-chlorine (Se-Cl) bond?
A selenium-chlorine bond should be more polar because of a greater difference in effective nuclear charge.
If you mix a typical aluminum ion (Al, atomic no. = 13) with a typical oxygen ion (O, atomic no. = 8), what compound is formed?
Al2O3
Is an ionic compound an example of a chemical compound, or is a chemical compound an example of an ionic compound?
An ionic compound is an example of a chemical compound.
Account for the observation that ethyl alcohol, C2H5OH, dissolves readily in water but dimethyl ether, C2H6O, which has the same number and kinds of atoms, does not.
Because dimethyl ether lacks an -OH group, it is significantly less polar than is ethyl alcohol and is not readily soluble in water.
Three kids sitting equally apart around a table are sharing jelly beans. One of the kids named Billy, however, tends only to take jelly beans and only rarely gives one away. If each jelly bean represents an electron, who ends up being slightly negative? Who ends up being slightly positive?
Billy ends up being slightly negative, while the two other kids are both slightly positive.
An individual carbon-oxygen bond is polar. Yet carbon dioxide is nonpolar because ________. (A) the molecule has an even number of electrons (B) it's symmetry (C) the electron-pulls of the two oxygen atoms are equal and opposite D- Both B and C
Both B and C
The neon atom tends NOT to lose any electrons to form a compound because ________.
It already has a full valence shell
How is it possible for a neutral molecule, such as water, to form an ion?
It can combine with a hydrogen ion to form a positively charged species.
What statement best describes a mole?
It is a very large number chemists use to count atoms or molecules.
Which of the following describes the term concentration?
It is the amount of solute in a given amount of solution.
Electron dot structures are not so important for understanding ________.
Metallic bonds
Which of the following elements has two valence electrons?
Mg
Which of the following elements will most likely form an ion with a +2 charge?
Mg
List the following bonds in order of increasing polarity: N-O < N-N < N-F < H-F N-N < N-O < N-F < H-F H-F < N-F < N-O < N-N N-N < N-O < H-F < N-F
N-N < N-O < N-F < H-F *Remember N-N first and H-F last
Which of the following molecules has the highest boiling point?
NH3
Which of the following elements has six valence electrons?
O
Which bond is most polar?
O-H
Which molecule is most polar?
O=C=S
Which of the following would be an ion with a double positive charge? an Mg atom that gains one electron an Mg atom that gains two electrons an Mg atom that loses one electron
an Mg atom that loses two electrons
Calcium fluoride, CaF2, is an example of ________.
an ionic compound
The principal source of an atom's electronegativity is the ________.
effective nuclear charge
How many covalent bonds would the O atom usually form?
2
Distinguish between a metal and a metal-containing compound.
Only one of these contains ionic bonds
True or False: The more shells in an atom, the lower its electronegativity. Explain.
Sometimes true and sometimes false; This holds true only within any one atomic group (vertical column).
Which would you expect to have a higher melting point: sodium chloride, NaCl, or aluminum oxide, Al2O3?
The aluminum oxide has a higher melting point because of the greater charges of the ions, and hence the greater force of attractions between them.
How does formula mass differ from atomic mass? The formula mass of a substance is the sum of the atomic masses of the elements is its chemical formula. The atomic mass is the mass of a single atom. The formula mass is the mass of the chemical formula and the atomic mass is the mass of the molecule. The atomic mass of a substance is the sum of the formula masses of the elements is its chemical formula. The atomic mass is the mass of a single atom.
The formula mass of a substance is the sum of the atomic masses of the elements is its chemical formula. The atomic mass is the mass of a single atom.
Given that the total number of atoms on our planet remains fairly constant, how is it ever possible to deplete a natural resource such as a metal?
The problem is with the expense of collecting metal atoms that are uniformly dispersed.
What happens if you were to place a dilute solution that is in a bag made of a semipermeable membrane and were to then suspend it in a very concentrated solution?
The size of the suspended bag would decrease.
Which of the following molecules can lose a proton to form the hydroxide ion, OH⁻?
The water molecule, H2O
The valence electron of a sodium atom does not sense the full +11 of the sodium nucleus. Why not?
There are two inner shells of electrons containing ten electrons shielding the sodium nucleus from sensing it.
Which of the following is the weakest form of interatomic attraction?
an induced dipole-induced dipole interaction
What surrounds the sulfur atom in SF4? four substituent fluorine atoms four substituent fluorine atoms plus one lone pairs of electrons four substituent fluorine atoms plus two lone pairs of electrons four substituent fluorine atoms plus three lone pairs of electrons
four substituent fluorine atoms plus one lone pair of electrons
During osmosis ________.
the water moves into the concentrated solution faster than it leaves
The neon atom tends NOT to gain any additional electrons because ________.
there is no more room available in its outermost occupied shell
When is the electronic geometry of a molecule not the same as its molecular shape?
when one or more of the substituents is a lone pair of electrons
How many chloride ions (Cl1-) are needed to balance the positive charge of a barium ion (Ba2+)?
2
How many oxide ions (O2-) are needed to balance the positive charge of a titanium ion (Ti4+)?
2
How many valence electrons does gallium (Ga, atomic no. = 31) have?
3
Which has the most atoms? A mole of gold A mole of helium a mole of lead
All have the same number of atoms
Ammonia is more polar than is borane because it ________. has a lone pair of electrons is less symmetrical than borane its hydrogens are not exactly opposite one another
All of the above
There is more gold in 1 km3 of the ocean than the amount of gold mined in all of recorded history. How come we do not mine the oceans? A- It would take too much energy B- It would cost too much C- It is too dilute to separate easily. D- All of the above
All of the above
Atoms of nonmetallic elements form covalent bonds, but they can also form ionic bonds. How is this possible?
An ionic bond results when a nonmetallic elements gains electrons to form an ion.
If you mix a typical iodine ion (I, atomic no. = 53) with a typical barium ion (Ba, atomic no. = 56), what compound is formed?
BaI2
What is the name for the following polyatomic ion? CH3CO2-
acetate
Polar molecules tend to be ________.
asymmetrical
What is the molecular shape of the SF_2SF2molecule?
bent
What is the molecular shape of the water molecule?
bent
In a solution of 77 percent nitrogen and 23 percent oxygen, which is the solvent?
nitrogen
Which of the following solutions is the most dilute? one liter of water with 1 gram of sugar one liter of water with 2 grams of sugar one liter of water with 5 grams of sugar one liter of water with 2 grams of sugar
one liter of water with 1 gram of sugar
What is the name for the following polyatomic ion? PO43-
phosphate
What property primarily determines the effect of temperature on the solubility of gas molecules?
the kinetic energy of the gas
The number of nonbonding (lone) electron pairs in the water molecule is ________.
two
