dusjagr & nano talk on open tools for agriculture research and learning
Presentation1class10chemistry1chemical.pptx
1.
2. There are two type of changes namely physical and chemical changes.
1.Physical Change
Melting of Ice
2.Chemical Change
• Rusting of Iron
• Formation of Curd
3. • milk is left at room temperature during summers.
• an iron tawa/pan/nail is left exposed to humid
atmosphere.
• grapes get fermented.
• food is cooked.
• food gets digested in our body.
• we respire.
4. Physical change Vs Chemical Change
Physical Change Chemical Change
Change is temporary Change is permanent
No new substance is formed. There is
change only in physical properties.
New substances are formed with
entirely different physical and
chemical properties
Change can be reversed by simple
physical methods
Change cannot be reversed by simple
physical methods
Energy may or may not be released or
absorbed
Energy is released or absorbed during
chemical change
5. Chemical reaction.
• Any change that involves chemical changes is called Chemical
reaction.
• The breaking and making of bonds between different atoms to
produce new substances is called Chemical Reaction.
6.
7. Why should a magnesium ribbon be cleaned before burning in the air?
• Solution:
Magnesium ribbon should be cleaned before burning in air because
Magnesium metal reacts with the atmospheric oxygen and forms
Magnesium Oxide (MgO) layer which is a very stable compound.
In order to prevent further reactions with Oxygen, it is therefore
necessary to clean the ribbon by to remove the layer of MgO.
12. • zinc + dil. sulphuric acid -> zinc sulphate + h2
• zinc + dil.hydrochloric acid -> zinc chloride + h2
Zinc liberates hydrogen gas when reacted with dilute hydrochloric acid, whereas copper does not. Explain why?
Zinc is more reactive than copper as Zinc is placed above Hydrogen and Copper is placed below hydrogen in the
activity series of metals. Because of this Zinc reacts with HCl whereas Copper will not react.
Z
H
C
