chapter 2 Flashcards
(20 cards)
Which one of the following elements is NOT one of the six most abundant in living organisms? carbon nitrogen iron phosphorous
iron
Chemistry can be defined as:
the study of the composition, properties, and reactions of matter
What does the octet rule state?
atoms are most stable when they have a full outer shell containing eight electrons.
A(n) ________ is the smallest unit of an element that still retains the properties of that element.
atom
When an atom is shown to have a minus one (Cl-) charge this means that the atom:
has gained an electron
Potassium (K) is an important ion in the human body due to:
its roles in nerve impulse transmission and muscle contraction
An ionic bond occurs when:
two oppositely-charged atoms are bonded together
The two types of covalent bonds are ________ and ________.
polar and nonpolar
Hydrogen bonds are:
individually weak but collectively strong
What are three of the special properties of water that make it such an important molecule in living things?
cohesion, ability to dissolve other molecules, temperature stability
Why does water have such a high heat of vaporization?
because of the hydrogen bonds between water molecules
A calorie can be defined as:
the amount of energy required to raise 1 gram of water 1 degree Celsius
The ability of water to dissolve many other molecules is due to:
its polarity
If you dissolve sodium chloride crystals in a beaker of water, water is considered the ___________and sodium chloride is the____________.
solvent, solute
Generally, water will dissolve other ___________ substances.
polar
What property of water makes it possible for aquatic organisms to survive during freezing periods?
ice is less dense than liquid water
An acidic solution has an excess number of _________ ions.
H+
A basic solution has an excess number of __________ ions.
OH-
If you have a solution with a pH of 7 and another solution with a pH of 5, how many more H+ ions does the pH 5 solution contain?
100 times
The pH of our blood must be within a finite range, and the two chemicals that help maintain blood pH are:
carbonic acid and bicarbonate
