Chemical vs. Physical Changes

Pranav R. & Dillon P.

Chemical Changes


  1. Chemical change is any change that results in the formation of new chemical substances. At the molecular level, chemical change involves making or breaking of bonds between atoms. These changes are chemical: iron rusting (iron oxide forms) gasoline burning (water vapor and carbon dioxide form).


Physical Changes

  1. Physical changes are changes affecting the form of a chemical substance, but not its chemical composition. Physical changes are used to separate mixtures into their component compounds, but can not usually be used to separate compounds into chemical elements or simpler compounds.

Practice Quiz: Chemical vs. Physical Changes

State if the following is a physical or chemical change:


1.Sodium Hydroxie dissolves in water


2.Water is heated and changed to steam


3.Iron rusts


4.Evaporation


5.Ice melting


6.Milk sours


7.Sugar dissolves in Water


8.Wood rotting


9.Pancakes cooking on a griddle


10.Grass growing in a lawn


11.A tire is inflated with air


12.Food is digested in the stomach


13.Water is absorbed by a paper towel


14.An iron scorches a shirt when you leave it on one spot too long


15.The tires on your car seem to be getting low in very cold weather


16.Your grandmothers silver tea set gets black with tarnish over time


17.Spray-on oven cleaner converts grease in the oven into a soapy material


18.An ordinary flashlight battery begins to leak with age and cant be recharged


19.Acids produced by bacteria in plaque cause teeth to decay


20.Sugar chars if overheated while making homemade candy


21.Hydrogen peroxide fizzes when applied to a wound


22.Dry ice evaporates without melting as time passes


23.Iron metal is melted


24.Wood burns in a fire


25.A rock is broken into small pieces


26.Wax is melted over a flame and then catches fire and burns

Answers to Quiz

Answers:

1.Physical

2.Physical

3.Chemical

4.Physical

5.Physical

6.Chemical

7.Physical

8.Chemical

9.Chemical

10.Chemical

11.Physical

12.Chemical

13.Physical

14.Chemical

15.Physical

16.Chemical

17.Chemical

18.Chemical

19.Chemical

20.Chemical

21.Chemical

22.Physical

23.Physical

24.Chemical

25.Physical

26.Chemical