Worksheet 1 Chemical Reaction and Equation

 

Ques 1 How can we say that in a given change a chemical reaction has taken place ?

 Ans 1 Whether a chemical reaction has taken place or not, we get to know when one or more of the following changes are seen:-

 (a)change in state. 

(b)change in colour 

(c)Evolution of gas 

(d)change in temperature .

Ques 2 Identify and write the chemical reaction for the given reaction:

Photosynthesis Boiling of water, Tearing of paper, Conversion of milk into curd.

Ans 2 Photosynthesis, Conversion of milk into curd.

Ques 3 Identify the reactant and product in the chemical equation: 

(i)Magnesium + Oxygen ________Magnesium Oxide  

(ii)Carbon + Oxygen _______ Carbon Dioxide .

Ans 3  (i) Magnesium + Oxygen (Reactants) ___ Magnesium Oxide (product)

(ii)  Carbon + Oxygen (Reactants )_____ Carbon Dioxide (Products).

Ques 4  Write the chemical equation of photosynthesis process and identify the reactants and products.

Ans 4 Reaction taking place during photosynthesis :

6Co² +H²o (Reactants) sunlight/chlorophyll C⁶H¹²O⁶+6O² (Products)

Ques 5 Pooja 's mother forget to keep to dough in refrigerator during summer. In morning some changes were observed in the kneaded dough . Are these changes physical or chemical ?

Ans 5 Chemical Change.