CHAPTER 2 TOPIC 2
A solution with a pH of 10 contains what concentration of hydroxyl ions [OH-]?
0.0001 moles/liter
A solution with a pH of 12 contains what concentration of hydroxyl ions [OH-]?
0.01 moles/liter
A solution with a pH of 1.5 contains what concentration of hydrogen ions [H+]?
0.03 moles/liter
The number of electron orbitals in the different electron shells is
1 in the 1st shell and 4 in the second shell
How many more electrons do oxygen atoms need to complete their valence shell?
2
The number of electrons needed to fill the different electron shells is
2 in the 1st shel and, 8 in the 2nd shell
How many more electrons do nitrogen atoms need to complete their valence shell?
3
How many covalent bonds do carbon atoms need to form with other atoms to complete their valence shell?
4
How many molecules of glycerol (C3H8O3; molecular mass = 92) would be present in 1 L of a 1 M (molar) glycerol solution?
6.02 x 10^23
You have a freshly prepared 0.1 M (molar) solution of glucose in water. Each liter of this solution contains how many glucose molecules?
6.02 x10^22
You have a freshly prepared 1 M (molar) solution of glucose in water. You carefully pour out a 100 mL sample of that solution. How many glucose molecules are included in that 100 mL sample?
6.02 × 1022
Which of the following would you expect to dissolve poorly in water?
A substance with a lot of nonpolar covalent bonds
What happens when you add an acid to water?
All of these answers are correct.
With regards to orbitals, which of the following statements is FALSE?
An orbital is a defined path that an electron follows as it orbits the nucleus.
Which of the following statements about bases is FALSE?
Bases cause the pH of the solution to decrease.
Pure water at room temperature has a concentration of 10-7 hydrogen ions (H+) and 10-7 hydroxyl ions (OH-). Why is this?
Because at any given moment 1 in 107 water molecules is broken apart into hydrogen and hydroxyl ions.
What is the difference between covalent bonds and ionic bonds?
Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms.
The molar mass of glucose is 180 g/mol. Which of the following procedures should you carry out to make a 1 M (molar) solution of glucose?
Dissolve 180 g of glucose in 0.8 L of water, and then add more water until the total volume of the solution is 1 L.
Why does the structure shown below fail to make sense chemically? H-C--C-H
Each carbon atom only has 3 covalent bonds.
Nitrogen (N) is more electronegative than hydrogen (H). Which of the following statements is correct about ammonia (NH3)?
Each hydrogen atom has a partial positive charge.
Which of the following statements regarding atomic particles is correct?
Electrons are negatively charged, protons are positively charged and neutrons are neutral.
What gives rise to the cohesiveness of water molecules?
Hydrogen bonds
Which of the following statements about hydrogen bonds is FALSE?
Hydrogen bonds are bonds between two hydrogen atoms.
Which of the following is not a molecule?
NaCl
What causes water molecules to be polar molecules?
Oxygen is more electronegative than hydrogen.
The charge on a water molecule is best described as being:
Somewhat less than minus one near the oxygen atom and somewhat less than plus one near each of the hydrogen atoms.
Which statement is true of ALL atoms that are anions?
The atom has more electrons than protons.
Polar molecules are often able to dissolve in water because
The partially charged regions of polar molecules are able to form hydrogen bonds with water molecules.
If you mix a solid, hydrophilic substance "X" and a solid, hydrophobic substance "Y" with water
X will likely dissolve in the water, forming a solution where X is the solute and water is the solvent. Y will likely not dissolve in the water.
MgCl2 is an example of
a compound
When atom "A" forms four single covalent bonds to complete its outermost electron shell, which is its 2nd electron shell, the electron orbitals within that shell will point towards the corners of
a tetrahedron
Atoms with incomplete valence shells may complete their shell by
all three of the other answers are correct, depending on the atom in question
When a sodium atom and a chlorine atom interact to complete their valence shells
an electron is transferred from sodium to chlorine, turning the sodium atom into a cation and the chlorine atom into an anion and allowing the two atoms to form an ionic bond
Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that
an electron may move to an electron shell farther away from the nucleus.
Magnesium is an example of
an element
If atom "A" is more electronegative than atom "B", than
atom "A" will attract electrons more strongly than atom "B"
Water is an example of
both a compound and a molecule
If the pH of a solution is decreased from 9 to 8, it means
concentration of H+ has increased tenfold (10X) compared to what it was at pH 9.
If the pH of a solution is decreased from 9 to 8, it means that the
concentration of H+ has increased tenfold (10X) compared to what it was at pH 9.
If the pH of a solution is increased from pH 5 to pH 7, it means that the
concentration of H+ is one hundred times less than it was at pH 5.
The order of chemical bonds from strongest to weakest is
covalent bonds, ionic bonds, hydrogen bonds, van der Waals interactions
The lowest energy mechanism by which a carbon atom may complete its valence shell is to
form 4 covalent bonds with other atoms
When two atoms share a pair of electrons, they
form a covalent bond
A mole of water (H2O) molecules and a mole of glucose molecules (C6H12O6)
have an equal number of molecules
The bonds that are broken when water vaporizes are
hydrogen bonds
The valence shell of an atom
may correspond to the first, second, third, fourth, fifth, sixth or seventh electron shells, depending on how many electrons the atom has
The correct order of the following atoms, from most to least electronegative, is
oxygen, nitrogen, carbon, hydrogen
What is the pH of a solution with a hydroxyl ion [OH-] concentration of 10-4 M?
pH 10
What is the pH of a solution with a hydrogen ion [H+] concentration of 10-4 M?
pH 4
What is the pH of a solution with a hydrogen ion [H+] concentration of 10-4 M? Correct!
pH 4
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
polar covalent bonds
The bonds in a water molecule are
polar covalent bonds
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
polar covalent bonds.
In humans, blood pH is around 7.4, and a decrease in blood pH to 6.4 would be fatal. A drop by 1 pH unit represents which of the following?
ten times as many H+ ions in the solution
Which of the following statements about electrons is FALSE?
the closer an electron is to the nucleus, the more strongly the electron is attracted to the nucleus and therefore the more potential energy the electron has
If the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, this means that
the concentration of H+ ions is tenfold higher in the cytoplasm than in the mitochondrial matrix.
The reactivity of an atom arises from
the existence of unpaired electrons in the valence shell
When a reversible chemical reaction reaches equilibrium
the forward and reverse reactions occur at the same rate
The further on average an electron is from the nucleus
the greater its potential energy