In an atom that has not undergone any type of chemical reaction, the number of electrons is always ______.
equal to the number of protons
Within a single element, you would expect to find ________.
atoms with differing numbers of electrons
The identity of an atom is determined by the ______.
number of protons in the nucleus
What are the primary elements that make up the human body?
carbon, oxygen, and hydrogen
Atomic number refers to what aspect of an atom?
proton number
A covalent bond involves ______.
the sharing of electrons
When a water molecule is formed, what type of bond is formed?
polar covalent bonds
The following is the chemical formula for the
molecule carbon dioxide: O=C=O. The two lines that connect each oxygen
atom to the one carbon atom represent ______.
two shared pairs of electrons
An ionic bond occurs between ________.
The charged atoms attract each other.
What is a hydrogen bond?
a weak interaction between partially charged hydrogen and elements with opposing partial charges
What must occur in order for a molecular signal to be recognized by its receptor molecule?
The shape of the signal must match the receptor.
When you pour salt into water and stir, the salt will
disappear. Which of the following statements describes both the salt
and the water correctly?
Water is the solvent; the salt is the solute.
A hydrophobic molecule ____________.
will not dissolve in water
To what does the term specific heat refer?
the amount of energy required to raise the temperature of a substance 1 degree Celsius
The compound HCl is acidic because of _______.
the capacity of HCl to dissociate into free hydrogen ions