5.7Chemical reactions that occur in the presence of light

Azneezal Ar-RashidSmk Sri Aman

95007 Sri Aman, Sarawak

Photosynthesis

Sunlight Breaks the water molecule into

hydrogen and oxygen Chlorophyll

Absorb light energy Carbon dioxide

Absorbed through stomata Changes into carbohydrate

Oxygen Oxygen is released

Water Water is absorbed

Photosynthesis equation Carbon dioxide + water + sunlight (chlorophyll)glucose + Oxygen

About photosynthesis

In photosynthesis, sunlight is absorbed by the chlorophyll in the leaves and a biochemical reaction is carried out

The importance of photosynthesis is : To maintain the percentage composition

of oxygen and carbon dioxide in the atmosphere

To provide food for plants

Decomposition reaction of chemical solution

Chlorine water In the presence of sunlight, chlorine is

decomposed into hydrochloric acid and oxygenwater + chlorine hydrochloric acid + hypochlorous

hypochlorous (light)oxygen

Without sunlight, no reaction will take place

Sodium hypochlorite solution Sodium hypochlorite solution is

decomposed into sodium chloride and oxygen in the presence of sunlight

sodium hypochlorite (light) sodium chloride + oxygen

No reaction will take place with out sunlight

Photographic paper / silver chloride Silver chloride is decomposed into

silver and chlorine gas when exposed to light

silver chloride (light)chlorine