FA#6

True or False: solids have the strongest molecular attraction compared to the molecular attraction of a gas

• true

• false

Answer explanation

solids have the highest, then liquids, then gases

Explain what the process is called when a gas changes into a liquid AND include if this is an endothermic or exothermic process.

Answer explanation

Condensation; exothermic process since heat energy is being removed

Kelly is part of a design team that makes winter jackets that are not too bulky. These jackets must have insulating material that slows down the transfer of heat energy (in other words, it needs to be REALLY warm). The material that was used was cotton. When this jacket was tested out it ended up not being very warm. What could Kelly do to change the design so that it is very warm (hint: think of other insulating materials)

Answer explanation

she could include fleece or wool since those materials allow for slower heat transfer

You’re an engineer at a company tasked to pick a metal for the front part of a supersonic jet that will hold it’s shape at the high temp (800 C) it will experience. Out of the 3 metals below--which one would you pick?

Tungsten

Melting point : 3,400 degrees C

Titanium

Melting point : 1700 degrees C

Magnesium

Melting point : 650 degrees C

Answer explanation

Titanium--Tungsten is way too high and Magnesium is way too low.

Explain why a substance having a higher melting point would require MORE energy to change to a liquid.

Answer explanation

if a substance has a higher melting point, that means they have a stronger molecule attraction--which would require more energy to break the chemical bonds

Substance A and B are both unknown gases. A scientist wants to know how much energy is needed to cool them down so that they change into a liquid. Substance A changes to a liquid but substance B stays the same. Explain what type of phase change process took place for substance A and what could the scientist do so that substance B can change into a liquid?

Answer explanation

condensation; cool it down even more and removed more energy

I understand that molecules in solids, liquids, and gases have different levels of molecular attraction based on their phase (pick either- agree, strongly agree, disagree, strongly disagree, neutral)

Answer explanation

this is up to you!

I understand how energy is transferred in the process of condensation (pick either- agree, strongly agree, disagree, strongly disagree, neutral)

Answer explanation

this is up to you!