Which of the following are considered pure substances?
2 answers:
Answer: A. Element and B. Compound
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Copper
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water
Heterogeneous mixture : It is a mixture that has non-uniform composition throughout the solution and the particle size or shapes are also different.There is a physical boundary between the dispersed phase and dispersion medium.
Homogeneous mixture: It is a mixture that has uniform composition throughout the solution and the particle size or shapes are not different.There is no physical boundary between the dispersed phase and dispersion medium.
Thus element and compound are pure substances.
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Answer: A. The reaction takes place in one step.
Explanation:
Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.
Molecularity of the reaction is defined as the number of atoms, ions or molecules that must colloid with one another simultaneously so as to result into a chemical reaction.
Order of the reaction is defined as the sum of the concentration of terms on which the rate of the reaction actually depends. It is the sum of the exponents of the molar concentration in the rate law expression.
Elementary reactions are defined as the reactions for which the order of the reaction is same as its molecularity and order with respect to each reactant is equal to its stoichiometric coefficient as represented in the balanced chemical reaction.
k= rate constant
a= order with respect to A
b = order with respect to B