This HW is due at the start of class on Friday (Feb 6), the day of our 2nd quiz. Doing these problems should also be good preparation for the quiz (and for the midterm on Feb 11).
Also, this week there will be an extra homework help section at 2 PM Wednesday in ISB 339.
1. What are atoms made of?
2. What components of an atom are most important in establishing its mass?
3.a) How does the mass of an oxygen atom compare to that of a hydrogen atom? How does it compare to that of a proton?
b) How does the mass of an carbon atom compare to that of a hydrogen atom?
c) How does the mass of an neon atom compare to that of a hydrogen atom?
d) How does the mass of an helium atom compare to that of a hydrogen atom?
4. a) What is deuterium? b) How does the mass of an carbon atom compare to that of a deuterium atom? c) Hydrogen is much more abundant than deuterium, but there is something about H that is a little odd or unconventional, regarding its nucleus, compared to that of other light elements. What is it?
5. What is the mass of an H2O molecule? What is the mass of a D2O molecule?
6. Thinking about the size of atoms:
a) Which is bigger: H or He?
b) Which is bigger: Li or O ?
c) Which is bigger: O or Ne ?
7. Why is it more difficult to explain the size of atoms than it is to explain the mass of atoms?
8. What part of the atom determines its size?
9. Suppose the average speed of an oxygen molecule in air at "room temperature" is 600 m/s. Would the average speed of a nitrogen molecule be the same, less or greater?
How about the average speed of a hydrogen molecule or a helium atom? Explain your reasoning briefly.
10. Suppose the average speed of a helium molecule in a gas is 500 m/s at -73 C. You add heat and observe that the average speed goes up from 500 m/s to 1000 m/s. What is the new temperature of the gas? [Give your answer in both C and K temperature scales.] Explain your reasoning briefly.
11. Suppose the average speed of an oxygen molecule in air at "room temperature" is 600 m/s. What is the average speed of a helium atom in that air?
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For Question 9, it says "How about the average speed of a hydrogen molecule." How does a hydrogen molecule look like? Is it the same as a hydrogen atom?
ReplyDeleteIt is 2 hydrogen atoms stuck together. H2.
ReplyDeleteWhat is the quiz going to include on Friday the 6th?
ReplyDeleteCan someone explain 10 briefly? I am a little confused.
ReplyDeleteWhat formulas are we supposed to be using? T ~1/2mv^2? or are there other ones that we need to know?
ReplyDeleteFor question 10, how would you calculate the new temperature?
ReplyDeleteIs there a formula we can use, like Pv=NRT?
for questions 9, 10 and 11, T~(1/2)*m*(v^2) is good to use.
ReplyDeleteIn 10), you are given the initial T, m and v.
Then, m stays the same, v goes up, (it doubles), and we ask the question, what happens to T?