Which reaction is a decomposition reaction? a. 2kclo3 → 2kcl + 3o2 b. 4na + o2 → 2na2o c. zns + 3o2 → 2zno + 2so2 d. 2nabr + caf2 → 2naf + cabr2

Answer : The decomposition reaction will be, (A)

Explanation :

Decomposition reaction : It is defined as the reaction in which a single larger compound decomposes to produce two or more smaller molecules as a product.

The general representation of decomposition reaction is :

From the given options,

(A) this reaction a decomposition reaction in which a potassium chlorate decomposes to give potassium chloride and oxygen gas as a product.

While the other reactions,

(B) this reaction is a combination reaction in which the two or more molecules combine to form a larger single molecule as a product.

(C) this is a double displacement reaction in which the cation and the anion of the two reactant exchange their places to give two another compounds as a product.

(D) this is a double displacement reaction in which the cation and the anion of the two reactant exchange their places to give two another compounds as a product.

Hence, the decomposition reaction will be,

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o