Bio 190 A: Chapter 2 Pre Lecture
Carbon has six protons, six electrons, and six neutrons. What is its atomic mass?
12
A mole of a certain substance has a number of particles equal to?
12g of Carbon
Oxygen has eight protons, eight electrons, and eight neutrons. What is its atomic mass?
16
The atomic mass of carbon is 12, and the atomic mass of hydrogen is 1. What is the molecular mass of a methane molecule (CH4)?
16
The atomic mass of hydrogen is 1, and the atomic mass of oxygen is 16. What is the molecular mass of a water molecule (H2O)?
18
A new element found on earth has four unpaired electrons in its outer shell. Predict the maximum number of bonds in which the new element can participate.
4
The chemical formula of glucose is C6H12O6. How many oxygen atoms are in one molecule of glucose?
6
Which of the following contributes to water's stability in a liquid state?
A high heat of fusion A high heat of vaporization
A Na+ ion forms when
A sodium atom loses an electron
Arrange the following solutions in order of increasing proton concentration. The solution with the lowest proton concentration should be placed at the top of the list.
Alkaline Neutral Acidic
Van der Waals interactions can form between?
Any atoms
A mole of any substance contains the same number of particles as they are
Atoms in exactly 12g of Carbon
Why is the atomic mass of carbon reported in the periodic table slightly greater than its predicted mass?
Because of the presence of a small amount of heavier isotopes
Why are atoms likely to share electrons?
Because they have unfilled outer electron shells
Ionic bond
Bond between a carbon and an anion
Hydrogen Bond
Bond between atoms with a partial positive and partial positive negative charges
Nonpolar covalent bond
Bond in which two atoms share electrons equally
Polar covalent bond
Bond in which two atoms share electrons unequally
What types of compounds minimize pH fluctuations in the fluids of living organisms?
Buffer and Buffer agent
Living organisms minimize charges in their internal pH using compounds called?
Buffers
Which of the following covalent bonds are nonpolar?
C-H O-O H-H
Polar covalent O-H bonds in water molecules enable hydrogen bonds to form between water molecules. Which of the following properties of water result from hydrogen bond formation?
Cohesion Adhesion Surface tension High Specific heat High heat of vaporization
The amount of solute (in grams) dissolved in a given volume of solution is the solution's...
Concentration
Neutral Solution
Contains equal numbers of OH- and H+ ions
Acidic Solution
Contains more H+ than OH- ions
Alkaline Solution
Contains more OH- than H+ ions
T/F: Electrons are found in the atom's nucleus.
False
In a polar covalent bond, the shared electrons are closer to the nucleus of the atom with?
Greater electronegativity
When water ionizes, it produces what ions?
H+ and OH-
Sodium hydroxide is a base because when dissolved in water it binds ___ ions that are in solution.
Hydrogen
The bond between the hydrogen atom and oxygen atom of separate water molecules is a(n) _______ bond.
Hydrogen
High specific heat, surface tension, and cohesion, are several properties of water involving ___ bonds.
Hydrogen (H)
When water is heated, the rate at which______ bonds break increases, and water molecules are converted to the _____ state.
Hydrogen (H); gaseous (gas or vapor)
What type of bond is indicated by the arrow in the diagram?
Hydrogen bond
Within an atom's structure, electrons can be found?
In cloud-like orbitals
What type of bond forms when a cation with a positive charge interacts with an anion carrying a negative charge?
Ionic
Which type of chemical bonds are easily broken in water?
Ionic bonds Hydrogen bonds
Which type of chemical bonds are easily broken in water?
Ionic bonds Hydrogen bonds
A covalent bond is one in which a pair of electrons
Is shared between two atoms
Water has a high heat of fusion. This means that...
Much energy must be withdrawn to cause water to change from a liquid to solid
Which of the following covalent bonds are polar?
N-H O-H
pH is defined as the ____ _____ to the base 10 of the ____ ion concentration.
Negative, logarithm, hydrogen
Electron
Negatively charged, located outside the nucleus
Atoms share a pair of electrons when they form a(n) _________ bond.
Non polar covalent
Atoms share a pair of electrons when they form a(n) __________ bond.
Non polar covalent
By mass, the most abundant element in living organisms is?
Oxygen
What four elements are the most common in living organisms?
Oxygen Hydrogen Carbon Nitrogen
A covalent bond in which the atoms share electrons unequally is a(n) _________covalent bond.
Polar
Amphipathic molecules have both ____ regions and ____ regions.
Polar (hydrophilic); nonpolar (hydrophobic)
A(n) ________ bond is when two atoms of different electronegatives share electrons.
Polar covalent
A(n) _________ bond is formed when two atoms of different electronegativities share electrons.
Polar covalent
Pure water can ionize into?
Positively charged protons (H+) and negatively charged hydroxide (OH+) ions
Proton
Positively charged, located in the nucleus
An atom's atomic number is based in the number of _______ it contains.
Protons
Van der Waals forces arise when
Random electron movement create short lived attractions
The concentration of a liquid is defined as the amount of _______dissolved in a unit volume of solution.
Solute
Which substance is acidic?
Stomach fluid
Polar covalent O-H bonds in water molecules enable hydrogen bonds to form between water molecules. Which of the following properties of water result from hydrogen bond formation?
Surface tension High heat of vaporization Adhesion High specific heat Cohesion
Which of the following statements are true of a polar covalent bond?
The atoms in the bond differ in electronegativity. The two atoms in the bond share the electrons unequally.
An atom's atomic number represents?
The number of protons
The atomic mass numbers reported in the periodic table do not exactly match calculations based on protons and neutrons due to?
The presence of different isotopes of the same element
When water freezes...
The rate of hydrogen bond breakage slows. Water molecules are packed into a more orderly formation.
Which of the following statements are true of a polar covalent bond?
The two atoms in the bond share the electrons unequally The atoms in the bond differ in electronegativity
Which of the following statements describe hydrophilic molecules?
They are soluble in water
What describes a hydrophobic molecule?
They contain many nonpolar covalent bonds They are relatively insoluble in water
Which of the following properties are shared by many chemical reactions that occur in cells?
They tend to proceed toward equilibrium They often require a catalyst They require energy
What is true about atoms having that have partially filled energy shells?
They tend to share, lose, or gain electrons They can form compounds
Nitrogen has three unpaired electrons in its outer shell. The maximum I'm number of covalent bonds that a nitrogen atom can form with other atoms while still remaining uncharged is?
Three
Neutron
Uncharged, located in the nucleus
Chemical reactions require a source of energy and also may require a substance called a(n) ______ that speeds up the reaction rate. Most chemical reactions proceed toward a state called ______, in which the rate of product formation equals the rate of reactant formation.
catalyst, equilibrium
An ionic bond forms when a positively charged ion, called a(n) ________, interacts with a negatively charged ion, called a (n) _________.
cation; anion
If an atom gains or loses a(n) _________, it acquired a net electrical charge and becomes an ion.
electrons
A covalent bond is one in which a pair of electrons....
is shared between two atoms
According to the __________ rule, atoms tend to be most stable when their outer shells are filled; this can be accomplished by gaining, losing, or sharing __________.
octet; electrons
An electron shell is composed of one or more ?
orbitals
The _____ of a solution is the negative base 10 logarithm of the H+ concentration of the solution.
pH
An amphipathic molecule has?
polar regions and non-polar regions
Atoms contain three types of particles, positively charged _________, negatively charged ________, and uncharged __________.
protons, electrons, neutrons
An electron __________ is composed of one or more orbitals.
shell
Water, with the chemical formula H2O contains, ________ hydrogen atom(s) and ______ oxygen atom(s).
two; one
Unpaired ________ electrons enable chemical bonds to form among atoms.
valence
