A Little Review for Us

What can be concluded from the portion of the graph where the temperature remains constant?

Answer explanation

When a state change graph like this has an area with a flat line- it represents MELTING, or FREEZING, or EVAPORATING: a state change!

Tags

NGSS.MS-PS1-4

At what point on the phase diagram does carbon dioxide exist as a solid, liquid and gas?

Answer explanation

This point is called the triple point!

Tags

NGSS.MS-PS1-4

How can carbon dioxide in a solid state be changed to a gas?

Answer explanation

Solid carbon dioxide is dry ice. Getting dry ice to become a gas is simply warming it up- and decreasing its pressure.

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NGSS.MS-PS1-2

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What changes in temperature and pressure will cause the substance in the gas phase to become a liquid?

Answer explanation

If you are going to move R to S: what do you need to do? GO BACK (temp decrease/down) and UP (pressure increase/up)

Tags

NGSS.MS-PS1-4

Which point (letter) is the substance in this graph a gas?

Answer explanation

You simply have to remember where gases are on these graphs! REMEMBER: if one isn't labeled- you might get lucky and see other questions DO have them labeled.

Tags

NGSS.MS-PS1-4

Where would you draw the electrons for this atom?

Answer explanation

Electrons "orbit" around the nucleus

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NGSS.MS-PS1-1

What is wrong with this diagram?

Answer explanation

The nucleus contains protons and neutrons.

Protons are positively charged.

Neutrons have no charge.

Electrons are in the cloud around the nucleus and are negatively charged.

Tags

NGSS.MS-PS1-1

Tell me about Substance A and Substance B.

Answer explanation

Different circles that are different "colors" or sizes represent different elements.

If they are touching, they are bonded in a molecule.

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NGSS.MS-PS1-1

Which figure is a compound? Which figure is a mixture? Which figure is an element?

Answer explanation

These types of questions get kids turned around a lot.

Figure 1 was an element.

Figure 2 was a compound.

Figure 3 was a mixture.

Tags

NGSS.MS-PS1-1

Tell me about what is happening here between iron and copper.

Answer explanation

This is creating a mixture-

A mixture of metals is called an alloy.

This would be an ALLOY of copper and iron because it is not forming a compound.

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