Module5　ALessoninaLab

详细内容

mon,too.There are many examples.You can make a physical change by tearing a piece of paper in two,or by cutting a piece of iron with lathe.Here paper is still paper,and the iron is still iron.

Another way of making physical change is dissolving somethin g in water.When you dissolve salt in
water,the salt disappears.You may think that a new substance has be en formed.But really there is no new substance.The salt is still salt.You can still taste it.So the dissolving of anything is a physical change.
When water freezes,the change is also a physical one.The water changes from liquid to solid.But it is still the same substance.That is why the freezing of anything is a physical change.?
1.It is not ________if a new substance is not formed in the change.?
A.a physical change
B.a chemical change?
C.change of state
D.a change?
2.The dissol ving of salt in water is ________.
A.a physical change
B.a chemical change?
C.hydrogen and oxygen
D.breaking up?
3.The change of the three states of water is ________.?
A.a chemical change
B.differen t substances?
C.a physical change
D.the same state?
答案:1.B　2.A　3.C??