Atoms & Basic Chemistry
Atoms are composed of
a. protons
b. neutrons
c. electrons
d. all of the above
d. all of the above - protons, neutrons, and electrons
Ionic bonds form between molecules that have
a. opposite charges
b. the same charge
c. no charges
d. neutral charges
a. 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
b. polar molecule
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
d. 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
b. occupy the space surrounding the nucleus.
The bond formed when two atoms share a pair of electrons is called a(an)
a. hydrogen bond
b. ionic bond
c. covalent bond
d. water bond
c. 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
b. water is polar and oil is nonpolar
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
c. are biological catalysts
The smallest particle of matter that can retain the chemical properties of carbon is a(
a. carbon molecule
b. carbon macromolecule
c. carbon atom
d. element
c. carbon atom.
Weak attractions between polar molecules are ______________ bonds.
hydrogen
Acidic solutions have a pH that is
a. less than 7
b. between 7 and 14
c. a negative number
d. more than 7
a. less than 7
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(an)
a. nucleus
b. cell
c. element
d. molecule
c. element.
The attraction that causes water to bond together to form drops is __________________.
cohesion
Due to the polarity of water, compounds that dissolve best in water contain
a. nonpolar bonds
b. ionic bonds
c. polar bonds
d. both b and c
d. both ionic bonds and polar bonds
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
The portion of an enzyme molecule into which a specific substrate bonds is called the __________ _______.
active site
Water heats and cools more ____________ than other liquids.
slowly
The molecule on which an enzyme acts is called the ________________.
substrate