When two intermediate chemical equations are combined, the same substance that appears in the same phase can be canceled out, provided that it is a reactant in one intermediate reaction and a product in the other reaction.

For example,

$2Al(s) + 2KOH(aq) + 6H_{2}O\rightarrow 2KAl(OH)_{4}(aq)+ 3H_{2}(g)$ ....(1)

$2KAl(OH)_{4}(aq) + 4H_{2}SO_{4}(aq) + 6H_{2}O(l)\rightarrow 2KAl(SO_{4})_{2}(aq)+ 12H_{2}O(s)$ .........(2)

Cancelling the common species in both the equations as follows.

$2Al(s) + 2KOH(aq) + 6H_{2}O\rightarrow \not{2KAl(OH)_{4}(aq)}+ 3H_{2}(g)$

$\not{2KAl(OH)_{4}(aq)}+ 4H_{2}SO_{4}(aq) + 6H_{2}O(l)\rightarrow 2KAl(SO_{4})_{2}(aq)+ 12H_{2}O(s)$

Therefore, on addition we get the equation as follows.

$2Al(s)+ 2KOH(aq) + 4H_{2}SO_{4}(aq) + 22H_{2}O(l)\rightarrow 3H_{2}(g)+ 2KAl(SO_{4})_{2} + 12H_{2}O(s)$

3 0

4 years ago

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What is always conserved in a chemical reaction?

Vaselesa [24]

The answer is b. Mass of the atoms

This is because of the law of conservation of mass. This means the mass in a system (in this case the reaction) can't change, so the quantity can't be added or removed

3 0

3 years ago