Chemistry
Define the following terms:
(a) Chemical change
(b) Chemical bond
(c) Effervescence
(d) Precipitate
Answer
(a) A chemical change is a permanent change in which the chemical composition of a substance is changed and one or more new substances with different chemical compositions and different properties are formed.
(b) A chemical bond is the force that holds the atoms of a molecule together, as in a compound.
(c) Effervescence is the formation of gas bubbles in a liquid during a reaction.
(d) Certain chemical reactions are characterized by the formation of insoluble solid substances called precipitate.
Related Questions
(a) What is a chemical reaction?
(b) State the conditions necessary for a chemical change or reaction.
Give an example of a reaction where the following are involved:
(a) Heat
(b) Light
(c) Electricity
(d) Close contact
(e) Solution
(f) Pressure
(g) Catalyst
Define :
(a) Photochemical reaction
(b) Electrochemical reaction.
Give one example in each case.
Give an example of each of the following chemical changes.
(a) A photochemical reaction involving 1. silver salt 2. water
(b) A reaction involving 1. blue solution 2. formation of a dirty green precipitate
(c) Two gases combine to form a white solid.
(d) Two solids combine to form a liquid.
(e) A reaction where color change is noticed.