Nom:___________________ date:_________________________

Chemical and Physical Changes

Introduction:Changes occur around us all the time. There are 2 types of changes; physical and chemical change. In a physical change, the molecules remain intact, so that no new substance is formed. During a chemical change, the molecules are broken down and the atoms rearrange in new molecules to give new substances.

We cannot see molecules with the naked eye to see if there is a physical or chemical change.

Instead, there are some clues that can help us determine if there is a chemical change present.The purpose of this experiment will be to observe the different reactions and describe if it is a physical or chemical change.

5 hints indicating that there is a chemical change present:

1. Effervescence 2. Unexpected colour change (formation of bubbles without using heat)

4. a new odour

3. precipitation (2 liquids forming a solide)

5. light or heat is produced

Mat erials : - test tubes -test tube bench - graduated cylinders

- test tube cleaners -latex gloves

-chemical products: chalk, vinegar, water, salt, oil, detergent, bleach

Procedure: Write your hypothesis first for each of the reactions in the box. Then mix together the indicated products in a test tube. Once you have mixed the products, observe and write the conclusion with the reason. Cleans the station at the end!

SUBSTANCES HYPOTHESIS

(physique ou chimique)

CONCLUSION

(physique ou chimique)

PROOF FOR

CONCLUSION

water + colouring

oil

Hypothesis: Conclusion:

Vinegar

chalk

Hypothesis: Conclusion:

Vinegar

salt

Hypothesis: Conclusion:

Vinegar

milk

Hypothesis: Conclusion:

DEMO (Mme.Siva)

Detergent

bleach

Hypothesis: Conclusion: