Chemistry 205 Chapter 2 Concept Explorations
Assignment Chapter 2
Concept Explorations
2.25. Average Atomic Mass
Part 1:
Consider the four identical spheres below, each with a mass of 4.00 g. a. Calculate the average mass of a sphere in this sample.
(4.00 + 4.00 + 4.00 + 4.00)/4= 16.00/4= 4.00g Part 2:
Now consider a sample that consists of four spheres, each with a different mass: blue mass is 4.00 g, red mass is 3.75 g, green mass is 3.00 g, and yellow mass is 1.25 g. * a. Calculate the average mass of a sphere in this sample.
(4.00 + 3.75 + 3.00 + 1.25)/4= 3.00g * b. How does the average mass for a sphere in this sample compare with the average mass of the sample that consisted just of the blue spheres? How can such different samples have their averages turn out the way they did? The sizes of these spheres are different. This can be caused by many factors such as the temperature could have changed the composition or size of the spheres in part two or the spheres could be different sizes. These factors are unknown, but what is known is that the masses are different, so the average mass changed for varying masses as compared to a constant mass.
Part 3:
Consider two jars. One jar contains 100 blue spheres, and the other jar contains 25 each of red, blue, green, and yellow colors mixed together. * a. If you were to remove 30 blue spheres from the jar containing just the blue spheres, what would be total mass of spheres left in the jar? (Note that the masses of the spheres are given in Part 2.)
70 X 4.00= 280.00g * b. If you were to remove 30 spheres from the jar containing the mixture (assume you get a representative distribution of colors), what would be the total mass of spheres left in the jar?
70 X 3.00= 210.00g * c. In the case of the mixture of spheres, does the average mass of the spheres necessarily represent the mass of an individual sphere in the sample?
No, because the average is not the exact mass for each sphere. It is an estimated number that represents
Concept Explorations
2.25. Average Atomic Mass
Part 1:
Consider the four identical spheres below, each with a mass of 4.00 g. a. Calculate the average mass of a sphere in this sample.
(4.00 + 4.00 + 4.00 + 4.00)/4= 16.00/4= 4.00g Part 2:
Now consider a sample that consists of four spheres, each with a different mass: blue mass is 4.00 g, red mass is 3.75 g, green mass is 3.00 g, and yellow mass is 1.25 g. * a. Calculate the average mass of a sphere in this sample.
(4.00 + 3.75 + 3.00 + 1.25)/4= 3.00g * b. How does the average mass for a sphere in this sample compare with the average mass of the sample that consisted just of the blue spheres? How can such different samples have their averages turn out the way they did? The sizes of these spheres are different. This can be caused by many factors such as the temperature could have changed the composition or size of the spheres in part two or the spheres could be different sizes. These factors are unknown, but what is known is that the masses are different, so the average mass changed for varying masses as compared to a constant mass.
Part 3:
Consider two jars. One jar contains 100 blue spheres, and the other jar contains 25 each of red, blue, green, and yellow colors mixed together. * a. If you were to remove 30 blue spheres from the jar containing just the blue spheres, what would be total mass of spheres left in the jar? (Note that the masses of the spheres are given in Part 2.)
70 X 4.00= 280.00g * b. If you were to remove 30 spheres from the jar containing the mixture (assume you get a representative distribution of colors), what would be the total mass of spheres left in the jar?
70 X 3.00= 210.00g * c. In the case of the mixture of spheres, does the average mass of the spheres necessarily represent the mass of an individual sphere in the sample?
No, because the average is not the exact mass for each sphere. It is an estimated number that represents