Textbook Chapter 2 - Biology - Chemistry of Life
compound
a substance made of atoms of different elements bonded together in a certain ratio. Common ____ in living things include water (H2O) and carbon dioxide (CO2)
ionic bond
forms through the electrical force between oppositely charged ions. Salt, or sodium chloride (NaCl), is a compound of Na+ and Cl-. Sodium chloride is held together by this.
covalent bond
forms when atoms share a pair of electrons. They are generally very strong, and depending on how many electrons an atom has, two atoms may form several covalent bonds to share several pairs of electron
element
one particular type of atom, and it cannot be broken down into a simpler substance by ordinary chemical means.
Ion
An atom that has gained or lost electrons
diatomic, or "two-atom," molecule
Example oxygen (O2)
Properties of Hydrogen Bonds
High specific heat - water resists changes in temperature Cohesion and Adhesion
hydrogen bond
an attraction between a slightly positive hydrogen atom and a slightly negative atom, often oxygen or nitrogen. ______ are part of the structures of proteins and of DNA, which is the genetic material for all organisms.
Adhesion
attraction among molecules of different substances. Ex. In a beaker, there is a slight curve
Cohesion
attraction of molecules in a substance, water molecules attract creating surface tension for spider to walk on and water beads come together on a windshield
polar molecules
have a region with a slight positive charge and a region with a slight negative charge. Ex. water, oxygen with negative charge and hydrogen with positive
solution
is a mixture of substances that is the same throughout and it is a homogeneous mixture. A solution has two parts. The solvent and solute.
A solute
is a substance that dissolves in a solvent.
atom
the smallest basic unit of matter.
solvent is
the substance that is present in the greater amount and that dissolves another substance.
molecule
two or more atoms held together by covalent bonds