BIOL 1009 - Q2
A solution with a pH of 10 contains what concentration of hydroxyl ions [OH-]?
0.0001 moles/liter
A solution with a pH of 4 contains what concentration of hydrogen ions [H+]?
0.0001 moles/liter
A solution with a pH of 2 contains what concentration of hydrogen ions [H+]?
0.01 moles/liter
A solution with a pH of 12 contains what concentration of hydroxyl ions [OH-]?
0.01 moles/liter (12=-log[H+])
How many more electrons do hydrogen atoms need to complete their valence shell?
1
How many covalent bonds do oxygen atoms need to form with other atoms to complete their valence shell?
2
How many electrons does it take to fill the first electron shell of a carbon atom (or any)?
2
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 electrons do carbon atoms have in their valence shell?
4
How many electrons do nitrogen atoms have in their valence shell?
5
How many molecules of glycerol (C3H8O3; molecular mass = 92) would be present in 1 L of a 1 M (molar) glycerol solution?
6.02 × 10^23
Which of the following statements most accurately describes an electron orbital?
An electron orbital is the three-dimensional space where an electron is found 90% of the time.
Which types of chemical reactions occur faster at equilibrium, the formation of products from reactants or reactants from products?
Both reactions occur at the same rate.
Which of the following represents a polar bond?
C-O
Which of the following statements regarding atomic particles is correct?
Electrons are negatively charged, protons are positively charged and neutrons are neutral.
The bonds that are broken when water vaporizes are
Hydrogen bonds
Water has a high specific heat because
Much of the energy absorbed by water goes to breaking hydrogen bonds between water molecules, rather than to raising the temperature of the water.
Which particles are found primarily in the nuclei of atoms?
Neutrons and protons
What causes water molecules to be polar molecules?
Oxygen is more electronegative than hydrogen
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.
MgCl2 is an example of
a compound
Oxygen gas (O2) is an example of
a molecule
If you make a model of a methane (CH4) molecule, the overall shape of the molecule will most closely resemble
a pyramid
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
Which of the following statements about bases is FALSE? a. Bases cause the pH of the solution to decrease. b. Bases cause the concentration of hydroxide (OH-) anions to increase and the concentration of H+ cations to decrease. c. Some bases reduce H+ concentrations by dissociating to form hydroxide (OH-) anions. d. Some bases reduce H+ concentrations by accepting hydrogen ions.
a. bases cause the pH of the solution to decrease
Magnesium is an example of
an element
Sodium is an example of
an element
Which of the following statements about hydrogen bonds is FALSE? a. The hydrogen atom involved in the bond has a polar covalent bond with a more electronegative atom. b. Hydrogen bonds are bonds between two hydrogen atoms. c. The hydrogen atom involved in the bond has a partial positive charge. d. The hydrogen atom involved in the bond is attracted to an electronegative atom with a partial negative charge
b. Hydrogen bonds are bonds between two hydrogen atoms.
One mole (mol) of glucose (molecular mass = 180 daltons) is
both 180 grams of glucose and 6.02 × 1023 molecules of glucose.
A hydrogen atom can complete its valence shell by a. forming a covalent bond with another hydrogen atom b. transferring an electron to another atom c. forming a covalent bond with a carbon atom d. all of the above
d. all of the above
Which subatomic particles are directly involved in chemical reactions between atoms?
electrons
A mole of water (H2O) molecules and a mole of glucose molecules (C6H12O6)
have an equal number of molecules
What gives rise to the cohesiveness of water molecules?
hydrogen bonds
When two atoms are equally electronegative, they will interact to form
nonpolar covalent bonds
The correct order of the following atoms, from most to least electronegative, is (nitrogen, carbon, hydrogen, oxygen)
oxygen, nitrogen, carbon, hydrogen
What is the pH of a solution with a hydrogen ion [H+] concentration of 10-1.5 M?
pH 1.5
What is the pH of an aqueous solution with a hydroxyl ion [OH-] concentration of 10-12 M?
pH 2
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 10-8 M?
pH 8
What is the pH of a solution with a hydroxyl ion [OH-] concentration of 10-4.5 M?
pH 9.5
What is the pH of a solution with a hydroxyl ion [OH-] concentration of 10-4.5 M?
pH 9.5 ([H+][OH-]=10^-14M) (pH=-log[H+])
The bonds in a water molecule are
polar covalent bonds
Which of the following do NOT comprise a significant fraction of the human body? (hydrogen, sodium, carbon, nitrogen)
sodium
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
An example of a hydrogen bond is the bond between:
the H of one water molecule and the O of another water molecule
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 further on average an electron is from the nucleus
the greater its potential energy
The order of chemical bonds from easiest to hardest to break is
van der Waals interactions, hydrogen bonds, ionic bonds, covalent bonds
Depending on how far an electron is moved from the nucleus
you can increase its potential energy by only certain amounts