Why is the melting of ice a physical change? It changes the chemical composition of water. It does not change the chemical compo
2 answers:
Answer: It does not change the chemical composition of water.
Explanation:
A physical reaction is defined as the reaction in which a change in shape, size takes place. No new substance gets formed in these reactions.
There is no change in chemical composition.
Example : melting of ice
A chemical reaction is defined as the reaction in which a change in chemical composition takes place. A new substance is formed in these reactions by breaking of old and making of new bonds.
Example: Oxidation of magnesium leads to formation of white magnesium oxide and is a chemical change.
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The question is incomplete, here is the complete question:
How many grams of zinc would be required to produce 9.65g of zinc hydroxide
Zn+2MnO₂+H₂O→Zn(OH)₂+Mn₂O₃
<u>Answer:</u> The mass of zinc required is 6.35 grams
<u>Explanation:</u>
To calculate the number of moles, we use the equation:
.....(1)
Given mass of zinc hydroxide = 9.65 g
Molar mass of zinc hydroxide = 99.4 g/mol
Putting values in equation 1, we get:
The given chemical equation follows:
By Stoichiometry of the reaction:
1 mole of zinc hydroxide is produced from 1 mole of zinc
So, 0.0971 moles of zinc hydroxide will be produced from = of zinc
Now, calculating the mass of zinc from equation 1, we get:
Molar mass of zinc = 65.4 g/mol
Moles of zinc = 0.0971 moles
Putting values in equation 1, we get:
Hence, the mass of zinc required is 6.35 grams