‫مدرسة البصيرة الدولية‬
BASEERAH INTERNATIONAL SCHOOL
Name:…………………….
Grade:……………………
Science
Worksheet 11
Date:………………..
Reversible and irreversible changes
What Are Reversible and Irreversible Changes?
1- Write in the spaces provided whether the changes below are reversible or
irreversible.
Mr. Elsayed Elmiligy
Page 1
‫مدرسة البصيرة الدولية‬
BASEERAH INTERNATIONAL SCHOOL
2- complete the notes on reversible changes.
Most changes can be split into either _ _ _ _ _ _ _ _ _ or _ _ _ _ _ _ _ _ _ _ _ .
Reversible changes are very common and occur when something changes but you
can easily get it back to its original state. An example of a reversible change is _ _
_ _ _ _ _ _ _ _ . This is when something breaks down into pieces that are too _ _ _
_ _ to be seen. They are still there they have ended up in between the _ _ _ _ _ _ _
particles. It is easy to get something that has dissolved back again. All you have to
do is _ _ _ _ _ _ _ _ _ the solvent and let the solute _ _ _ _ _ _ _ _ _ _ _ . It is easy
to tell if a solid has not dissolved because the liquid will turn _ _ _ _ _ _ .
Another reversible reaction is a change of _ _ _ _ _ . This is where a substance
either evaporates, _ _ _ _ _ _ _ _ _ , _ _ _ _ _ _ _ or _ _ _ _ _ . In order to make a
substance melt or evaporate then you need to _ _ _ _ it up. In order to make a
substance condense or freeze then you need to _ _ _ _ it down. When a substance
changes state all that happens is the particles of that substance have enough energy
to be either a solid, liquid or a gas. They stay as the same _ _ _ _ _ _ _ _ _ .
Substance Condense Evaporate Cloudy Reversible Heat Cool State
Melt Freeze Dissolving Irreversible Crystallise Solvent Small
3- make observations on the following changes
Mr. Elsayed Elmiligy
Page 2
‫مدرسة البصيرة الدولية‬
BASEERAH INTERNATIONAL SCHOOL
4- State whether the changes are reversible or irreversible.
Mr. Elsayed Elmiligy
Page 3
‫مدرسة البصيرة الدولية‬
BASEERAH INTERNATIONAL SCHOOL
5- Jane puts some green powder into water. Bubbles appear in the water and the
powder disappears. The water turns green. Jane says that this is an irreversible
change.
(i) Which observation shows Jane that this change is irreversible?
……………………………………………………………………………….…..…
………………………………………………………………………………………
(ii) Explain why?
……………………………………………………………………………….…..…
(iii) Write one reversible change that is caused by
heating?.....................................................................................................
iv) Explain why?
……………………………………………………………………………….…..…
Mr. Elsayed Elmiligy
Page 4