Atoms & Basic Chemistry
The nucleus is composed of
a. protons and neutrons
b. protons and electrons
c. protons only
d. all of the above
protons and neutrons
Ionic bonds form between molecules that have
a. opposite charges.
b. the same charge.
c. no charges.
d. neutral charges.
opposite charges.
A molecule, like water, that has a partial positive charge on one side and a partial negative charge on the other side is called
a. nonpolar molecule.
b. polar molecule.
c. charged molecule.
d. bipolar molecule.
polar molecule
Which of the following is NOT an organic macromolecule?
a. carbohydrate
b. oxygen
c. lipid
d. nucleic acid
oxygen
An enzyme
a. is not used up when catalyzing a reaction.
b. lowers the activation energy of a reaction.
c. bonds with a substrate molecule at the enzyme's active site.
d. all of the above.
all of the above
The electrons of an atom
a. are found in the nucleus along with the protons.
b. occupy the space surrounding the nucleus.
c. have a positive charge.
d. are attached to the positive charge of neutrons.
occupy the space surrounding the nucleus.
The bond formed when two atoms share a pair of electrons is called a(n)
a. hydrogen bond.
b. ionic bond.
c. covalent bond.
d. water bond.
covalent bond
When placed in the same container, oil and water do not mix because
a. they are both polar.
b. water is polar and oil is nonpolar.
c. they are both nonpolar.
d. water is nonpolar and oil is polar.
water is polar and oil is nonpolar
All organic compounds contain the element
a. carbon.
b. nitrogen.
. calcium.
d. sodium.
carbon
Enzymes
a. are able to heat up molecules so that they can react.
b. always provide carbon dioxide for chemical reactions.
c. are biological catalysts.
d. absorb excess heat so that reactions occur at low temperatures.
are biological catalysts
The smallest particle of matter that can retain the chemical properties of carbon is a(n)
a. carbon molecule.
b. carbon macromolecule.
c. carbon atom.
d. element.
carbon atom.
The stronger the bonds in a compound, the ___________________ the energy required to break the bonds.
greater
Acidic solutions have a pH that is
a. less than 7.
b. between 7 and 14.
c. a negative number.
d. more than 7.
less than 7
Which of the following organic molecules are classified as carbohydrates?
a. amino acids
b. fatty acids
c. nucleotides
d. sugars
sugars
The starting materials for chemical reactions are called _________________, while the new substances that are formed are called _______________.
reactants; products
A substance that is composed of only one type of atom is called a(n)
a. nucleus.
b. cell.
c. element.
d. molecule.
element.
In a chemical reaction, when more energy is released from bonds than is needed to break the bonds, the reaction is said to be _________________.
exergonic (exothermic)
Due to the polarity of water, compounds that dissolve in water contain
a. nonpolar bonds.
b. ionic bonds.
c. polar bonds.
d. both b and c.
both ionic bonds and polar bonds
Long chains of nucleotides are called _____________ ______.
nucleic acids
The energy needed to start a chemical reaction is called ______________ ___________.
activation energy
A(n) _______________ is a group of atoms held together by covalent bonds.
molecule
When an enzyme is missing from a reaction, the peak of the energy curve will be _______________ than normal.
higher
Water can dissolve most substances because it has a property known as ______________.
polarity
The organic molecule that has a glycerol molecule with fatty acid chains attached is called a ____________.
lipid
Atoms will only react when they
a. have a full set of electrons.
b. have an incomplete set of electrons.
c. have the opportunity to.
d. They react all of the time.
have an incomplete set of electrons.