Learning check

Once you have watched the video, check your learning with this quiz.

Chemistry: The study of matter and how it changes

What is matter?

  • Anything that has a mass.
  • [Anything you can touch, see, or see in an instrument (e.g. a telescope or a microscope).]


  • Iron
  • Wood
  • Air
  • Water
  • Plastic

How does matter change? Examples:

  • Ice melts
  • Iron corrodes
  • Children grow
  • Plants grow
  • Petrol burns
  • … and much, much more!

Phase transitions

Melting & solidification (freezing)

Ice melts:

  • Solid water, H2O(s), with energy added gives liquid water, H2O(l).
  • H2O(s) + energy → H2O(l)

Water freezes:

  • Liquid water, H2O(l) freezes and forms solid water (ice), H2O(s). At the same time, energy is released.
  • H2O(l) → H2O(s) + energy

Evaporation & condensation

Liquid water evaporates:

  • Liquid water, H2O(l), with energy added gives water vapor, H2O(g)
  • H2O(l) + energy → H2O(g)

Water vapor condenses:

  • Water vaper condenses into liquid water. At the same time, energy is released.
  • H2O(g) → H2O(l) + energy

Phase transitions.Phase transitions.

Sublimation & deposition

Matter passes from solid to gas without passing liquid state.

Example: Solid iodine, I2(s), sublimates with added energy, and forms iodine vapor, I2(g).

  • I2(s) + energy → I2(g)

Iodine sublimes.Iodine sublimes.

Iodine deposits.Iodine deposits.

Ionization & deionization

If enough energy is added, one or more electrons are removed from the atom. This creates positively charged ions.

Most abundant state of matter in the universe: The sun and all the stars are made of plasma.

Our sun and most stars are made of plasma.Our sun and most stars are made of plasma.

Cookies user preferences
We use cookies to ensure you to get the best experience on our website. If you decline the use of cookies, this website may not function as expected.
Accept all
Decline all
Read more
Tools used to analyze the data to measure the effectiveness of a website and to understand how it works.
Google Analytics
Set of techniques which have for object the commercial strategy and in particular the market study.
DoubleClick/Google Marketing