Name: _________________________________________________________
Block: _____
Date: ______________
Problem Set #1 (U1, L1-5)
Vocab/Concepts: Fill in the blanks or circle the correct response in brackets.
1. Matter is anything that __has mass and takes up space_____________.
2. Opposite charges ___attract______ each other. Similar charges ___repel_______ each other.
3. Two charged particles will exert a stronger force on each other when they are [close together] [far apart].
4. If you increase the charges on two particles, the force between them becomes [weaker] [stronger].
5. Energy is the ability to make matter ________move_______________.
6. Energy that is stored based on the position of objects is called __potential_______ energy.
7. Energy of an object based on its motion is called ______kinetic_______________ energy.
8. ____density________ measures how tightly the matter in an object is packed into the space it takes up.
Problems:
9. Consider the example shown below, where two positively-charged particles, A and B, are one nanometer apart.
(Note: A nanometer, nm, is one billionth of a meter.)
+
A
1 nm
+
B
a. In what direction is the force on particle A? ______left_______ on particle B? ______right_____________
b. If particles A and B were 2 nm apart instead of 1 nm, would the force on each one be stronger or weaker?
Explain.
If the distance increased, the force on each would be smaller. The further away charged objects are, whether they
are attractive or repulsive, the weaker the force.
10. Consider the example shown below, in which three particles are near each other.
A
C
B
1 nm
1 nm
+
–
+
a. Is the force between A and B attractive or repulsive? _____repulsive____________
b. In what direction is the net force on particle A? ______right__________________
c. In what direction is the net force on particle B? _______left_________________
11. In Intro Physics, you may have learned that matter cannot be created or destroyed. What do you think happens to
the matter in a piece of firewood when it is burned?
When firewood is burned, a chemical reaction occurs that causes the matter to change its form. The particles of
matter are not created or destroyed, but change. Some become a gas, while others become react to form a black
solid. The same amount of total stuff is there at the end as there was at the beginning.
12. A student was measuring the mass and volume of objects to find their density. Use the data in the table below to
calculate the density of each substance. Show your work.
Object
metal screw
plastic pipe
Mass of Object (g)
22.74 g
122.7 g
Volume of water alone (mL)
10.6 mL
104 mL
Volume of water + object (mL)
13.4 mL
175 mL
Volume of screw = 13.4 mL – 10.6 mL = 2.8 mL
Density of screw = mass/volume = 22.74 g / 2.8 mL = 8.12 g/mL
Density of screw = ________8.12 g/mL____________________
Volume of pipe = 175 mL – 104 mL = 71 mL
Density of pipe = mass/volume = 122.7 g / 71 mL = 1.73 g/mL
Density of pipe = _________1.73 g/mL____________________
13. One common plastic used to make pipes is polyvinyl chloride (PVC). It is known that the density of PVC is between
1.3 and 1.5 g/mL. A builder needs to use PVC pipe for a particular project. Should he use the pipe described in #12?
Explain.
The builder should not use the pipe from problem 12. The density calculate was 1.73 g/mL, which is outside of the
range of PVC, therefore the material cannot be PVC. He should go to Home Depot (or a local hardware store) and
demand his money back.
14. Imagine that your friend has asked you to use your chemistry expertise to help her solve a problem. She recently
found in her grandmother’s attic a necklace made of a silvery metal. She thinks that it may be platinum, which
would be worth a lot of money, but she’s not sure. It just so happens that you have a sample of pure platinum in
your chemical stock room. Your friend thinks that with your knowledge of properties of matter, you can help her
determine if the necklace is truly made of platinum. Describe a procedure you could use to gather data that could
either support or discredit the hypothesis that the necklace is made of platinum. Provide numbered steps.
1)
2)
3)
4)
5)
6)
7)
Determine the mass of your piece of platinum
Find the volume of your piece of platinum using the water displacement method
Calculate the density of the platinum
Determine the mass of silvery metal
Find the volume of the silvery metal using the water displacement method
Calculate the density of the silvery metal
Compare the densities (be careful, if the numbers are slightly different, it may be experimental error, so you
should run your tests multiple times to gain more confidence in the results.