Physiology: ?Concentration and Dilution 
CONCENTRATION AND DILUTION
Physiology 1, Las Positas College Name:
In science, concentration is a measure of the number of particles (solutes) in a given volume. If one room has 100 people in it, and a room of equal size has 50 people, one can say that the concentration of people in one room is twice that of the other. Quite simple, isn’t it?
On a molecular level, consider whether you put one lump or two of sugar, or no sugar at all, in your coffee. If you use two lumps, you prefer twice as many molecules of sucrose per cup than a person who uses one lump. If you prefer no sugar, the concentration of sucrose molecules is 0 molecules/cup.
If your coffee is too strong or too sweet, you might add a little water. Scientifically speaking, you are diluting your coffee. Dilution reduces the concentration of a solution. If the coffee is still too strong, and you dilute it again, you are performing a serial dilution – that is, you are reducing the concentration in successive steps until the result is satisfactory.
In medicine, the satisfactory result is often that a medicine is strong enough to have its desired effect but weak enough to avoid killing the patient. Thus, it is important to have a firm enough grasp of the concept of concentration to understand it instinctively and be able to manipulate commonly used units of concentration.
What Happens When Something Dissolves
When you add a teaspoon of sugar (sucrose) to your coffee or tea, you are adding and dispersing more than eight septillion (8 x 1024) individual sucrose molecules. These molecules are too small to see, but you can taste them.
While table sugar is made up of sucrose molecules (remember covalent compounds from chemistry?), table salt (sodium chloride) is a very different kind of chemical compound, an ionic compound. It is made up of two smaller particles, a sodium ion and a chlorine ion. Sodium chloride can be made in the laboratory (don’t try this at home!) by
Physiology 1, Las Positas College Name:
In science, concentration is a measure of the number of particles (solutes) in a given volume. If one room has 100 people in it, and a room of equal size has 50 people, one can say that the concentration of people in one room is twice that of the other. Quite simple, isn’t it?
On a molecular level, consider whether you put one lump or two of sugar, or no sugar at all, in your coffee. If you use two lumps, you prefer twice as many molecules of sucrose per cup than a person who uses one lump. If you prefer no sugar, the concentration of sucrose molecules is 0 molecules/cup.
If your coffee is too strong or too sweet, you might add a little water. Scientifically speaking, you are diluting your coffee. Dilution reduces the concentration of a solution. If the coffee is still too strong, and you dilute it again, you are performing a serial dilution – that is, you are reducing the concentration in successive steps until the result is satisfactory.
In medicine, the satisfactory result is often that a medicine is strong enough to have its desired effect but weak enough to avoid killing the patient. Thus, it is important to have a firm enough grasp of the concept of concentration to understand it instinctively and be able to manipulate commonly used units of concentration.
What Happens When Something Dissolves
When you add a teaspoon of sugar (sucrose) to your coffee or tea, you are adding and dispersing more than eight septillion (8 x 1024) individual sucrose molecules. These molecules are too small to see, but you can taste them.
While table sugar is made up of sucrose molecules (remember covalent compounds from chemistry?), table salt (sodium chloride) is a very different kind of chemical compound, an ionic compound. It is made up of two smaller particles, a sodium ion and a chlorine ion. Sodium chloride can be made in the laboratory (don’t try this at home!) by