The balanced chemical reactions follow the Law of mass conservation. The answer of question 1, 2, 3, 4, and 5 is D, C, B, C, and B respectively.
Balanced Equation:
A chemical equation is called balanced when the number of element in reactant and product is equal.
Hence, For first reaction:
[tex]\rm \bold{4Al + 3O_2 \rightarrow 2Al_2O_3}[/tex] is correct.
For second reaction:
[tex]\rm \bold{2C_2H_6 + 7O_2 \rightarrow4CO_2 + 6H_2O}[/tex] is correct.
Combination Reaction:
In this two or more molecule combine to a single molecule.
[tex]\rm \bold{2CO(g) + O_2(g) \rightarrow CO_2(g) }[/tex]
Decomposition Reaction:
In this a substance is broken down into smaller molecules.
[tex]\rm \bold { CaCO_3 \rightarrow CaO + CO_2}[/tex]
Single replacement:
In this one element is replaced by another one.
[tex]\rm \bold{Mg + H_2SO_4 \rightarrow MgSO_4 + H_2}[/tex]
Double replacement:
In this two ionic compounds exchange their ions.
Example: [tex]\rm \bold{ BaCl_2 + K_2CO_3 \rightarrow BaCO_3 + 2KCl}[/tex]
Therefore we can can conclude that the chemical reactions follow the Law of mass conservation.
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