Question

please tell the ans its urgent please solve it out
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Answer 1

Answer:

2)

a)Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions

Answer 2

Answer:

1 a.process that involves rearrangement of the molecular or ionic structure of a substance, as distinct from a change in physical form or a nuclear reaction

b.minimum amount of energy,speed of reaction, rate of reaction etc...

2.i)the substance which change into new substance cannot be reversible.

ii)A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds. The bond may result from the electrostatic force of attraction between oppositely charged ions as in ionic bonds or through the sharing of electrons as in covalent bonds.

iii)Effervescence is the formation of gas bubbles in a liquid by a chemical reaction.

iv)the action or process of precipitating a substance from a solution.

3.a bulb

b.sunlight

c.wire

d.disease

e.salt in water

f.a truck fitted with 8 tyre

nickel, platinum