# science- I need help!

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1. How do you know when something is gas?

2. What is gas made of? [I think it's molecules and atoms?]

3. How do you know when something is matter? [I believe that when something has a mass and volume..its matter. Is that correct?

4. Is gas matter? [This question got me confused because we were taught that gas is a form of matter, but it has no definite shape or volume so why is it matter?

5. Does air take up space? How do you know?

6. Does air always take up the same amount of space? [I think it's no but I don't know how to explain it.]

These are the questions from my worksheets that I mostly have troubles with and I need to be cleared up on it please. Thank you.

• science- I need help! -

1) well, how do you know if something is solid or liquid? Now compare that to what is not solid or liquid, that is a gas.

2) correct

3) correct.

4) Gasses have volume, even if it is not definite. The also have mass.

5) Does air take up space? What is in the atmosphere?

6) No. Air is compressible (think of a tire pump, or a ballon).

• science- I need help! -

1. Well you cant see a gas, but you can feel it.

5. Air does take up space but not in the same amount.

6. Since air has no definite shape or volume, it does not take up the same amount of space. Like there would be more air in a party balloon than in a 35 mL syringe.

Is all of this correct?

• science- I need help! -

One is correct. The other two are almost there, they need rewording....on 5 do you mean the volume can vary with pressure and temp...on 6, do you mean that compressed gas has more mass than an equal weight of uncompressed gas, both of the same volume?

• science- I need help! -

For number one I means that air can take up different amount of space. For example, there will be more amount of air in a small balloon than in a bigger balloon.

And for number 6, I meant something similar to 5.

• science- I need help! -