Chapter 2.1 Atoms
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 vaporization -A high heat of fusion
Match each type of chemical bond with the correct description.
-Ionic bond - Bond between a cation and an anion -Hydrogen bond- Bond between atoms with partial positive and partial negative charges -Polar covalent bond- Bond in which two atoms share electrons unequally -Nonpolar covalent bond- Bond in which two atoms share electrons equally
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 oxygen atom has eight protons, eight electrons, and eight neutrons. Its atomic mass is expected to be ______.
16
If the atomic mass of carbon is 12, and the atomic mass of hydrogen is 1, then the molecular mass of a methane (CH4) molecule would be Blank______.
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)?
2 + 16 = 18
Nitrogen has three unpaired electrons in its outer shell. The maximum number of covalent bonds that a nitrogen atom can form with other atoms while still remaining uncharged is
3
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
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 (4)
A mole of an element contains:
6.022 x 10^23 atoms
When water ionizes, it produces what ions?
H+ and OH-
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?
High heat of vaporization, high specific heat, surface tension, adhesion, cohesion
The amount of solute (in grams) dissolved in a given volume of solution is the solution's:
High specific heat High heat of vaporization Adhesion Surface tension Cohesion
High specific heat, surface tension, and cohesion are several properties of water involving _____ bonds.
Hydrogen
The bond between the hydrogen atom and oxygen atom of separate water molecules is a(n) ___ bond.
Hydrogen
The bond between the hydrogen atom and oxygen atom of separate water molecules is a(n) ___ bond.
Hydrogen (hydrogen bond)
What type of bond is indicated by the arrow in the diagram?
Hydrogen bond
A(n) _____ bond forms when a cation with a positive charge interacts with an anion carrying a negative charge.
Ionic
What characteristics describe hydrophobic molecules? Multiple select question. They are relatively insoluble in water. They contain many nonpolar covalent bonds. They have atoms with partial positive and partial negative charges. They form micelles when placed in water.
They are relatively insoluble in water. They contain many nonpolar covalent bonds.
A(n) _____ bond forms when a cation with a positive charge interacts with an anion carrying a negative charge.
They tend to proceed toward equilibrium. They often require a catalyst. They require energy.
Which of the following statements are true about atoms that have partially filled energy shells?
They tend to share, lose, or gain electrons. They can form compounds.
Van der Waals interactions can form between:
any atoms
Living organisms minimize changes in their internal pH using compounds called
buffers
What four elements are the most common in living organisms?
carbon, hydrogen, oxygen, nitrogen
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
The amount of solute (in grams) dissolved in a given volume of solution is the solution's:
concentration
Atoms share a pair of electrons when they form a ____ bond
covalent
Which types of chemical bonds are easily broken in water?
hydrogen bonds and ionic bonds
When water is heated, the rate at which ___ bonds break increases, and water molecules are converted to the ___ state.
hydrogen; gaseous
When water is heated, the rate at which _____ bonds break increases, and water molecules are converted to the ____ state.
hydrogen; gaseous
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: Multiple choice question. covalent bonds must replace hydrogen bonds to form ice. much energy must be added to cause gaseous water to change to the liquid state. much energy must be withdrawn to cause water to change from a liquid state to solid.
much energy must be withdrawn to cause water to change from a liquid state to solid.
pH is defined as the ______________ _______________ to the base 10 of the ___________________ ion concentration.
negative logarithm , [H+] (Hydrogen)
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 (valence electrons)
The ______ of a solution is the negative base 10 logarithm of the H+ concentration of the solution.
pH
A(n) ______ bond is formed when two atoms of different electronegativities share electrons.
polar covalent
Pure water can ionize into: Multiple choice question. positively charged hydroxide (OH+) ions and negatively charged protons (H-). negatively charged dihydroxide (H2-) ions and positively charged oxygen ions (O+). positively charged dihydroxide (H2+) ions and negatively charged oxygen ions (O-). positively charged protons (H+) and negatively charged hydroxide (OH-) ions.
positively charged protons (H+) and negatively charged hydroxide (OH-) ions.
Atoms contain three types of particles, positively charged ___ , negatively charged ___ , and uncharged ____
protons, electrons, neutrons
Van der Waals forces arise when:
random electron movement creates short-lived attractions
The concentration of a liquid is defined as the amount of ______ dissolved in a unit volume of solution.
solute
What does the atomic number of an atom represent?
the number of protons in an atom
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
Which of the following statements describe hydrophilic molecules?
they are soluble in water
Water, with the chemical formula H2O, contains __ hydrogen atom(s) and __ oxygen atom(s).
two, one
When water freezes: Multiple select question. water molecules are packed into a more orderly formation. the rate of hydrogen bond breakage slows. the specific heat of water changes. water is no longer hydrophilic.
water molecules are packed into a more orderly formation. the rate of hydrogen bond breakage slows.
Match the type of solution with its appropriate description. Acidic, Alkaline, Neutral. H+ vs OH- [more, less, equal]
Acidic —> more H+ than OH− Alkaline —> more OH− than H+ Neutral —> Contains equal numbers of H+ and OH−
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
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/valence shells.
An ionic bond forms when a positively charged ion, called a(n) ___, interacts with a negatively charged ion, called a(n) ___ .
Blank 1: cation or cations Blank 2: anion or anions
Amphipathic molecules have both ___ regions and ___ regions.
Blank 1: polar or hydrophilic Blank 2: nonpolar , hydrophobic, non-polar, or non polar
What type(s) of compound(s) minimize pH fluctuations in the fluids of living organisms?
Buffer, Buffering Agent
Living organisms minimize changes in their internal pH using compounds called Blank______.
Buffers
Consider the following covalent bonds. Identify the ones that are nonpolar.
C-H, H-H, O-O
An ionic bond forms when a positively charged ion, called a(n) ___ , interacts with a negatively charged ion, called a(n) ___ .
Cation (positive) , Anion (Negative)
Which of the following statements are true of an amphipathic molecule?
It has polar regions. It has non-polar regions. (Doesnt dissolve completely in water) (Isn't electrically neutral)
Which of the following covalent bonds are polar? O-H N-H H-H C-H C-C
O-H N-H
Which of the following covalent bonds are polar?
O-H and N-H
By mass, the most abundant element in living organisms is:
Oxygen
