Question

In a reaction, 25 g of reactant AB breaks down into 10 g of product A and an unknown amount of product B. Using the law of conservation of mass, how much does product B weigh?​

Answer 1

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$\large\underline{\underline{\red{\sf Question:-}}}$

In a reaction, 25 g of reactant AB breaks down into 10 g of product A and an unknown amount of product B. Using the law of conservation of mass, how much does product B weigh?

$\large\underline{\underline{\red{\sf Before\:we\:procced\:we\:must\:know:-}}}$

$\underline{\pink{\sf Law\:of\: Conservation\:of\:Mass:}}$

This was given by Antoine van Lavosier . It states that in a chemical reaction the mass of Reactants is equal to the mass of products. Or in other words in a chemical reaction mass is nether created nor destroyed.

$\boxed{\green{\bf Mass\:of\: Reactants=Mass\:of\: Products}}$

$\large\underline{\underline{\red{\sf Required\:Answer:-}}}$

Given that in a reaction , 25 g of reactant AB breaks down into 10 g of product A and an unknown amount of product B. That is ;

$\boxed{\green{\bf \pink{\dag}\:\:\underset{25g}{AB}\:\:\:\xrightarrow{Decomposition} \:\:\underset{10g}{A} \:\:+\:\:B}}$

$\underline{\sf \blue{By\:Law\:of\: Conservation\:of\:Mass:}}$

$\tt:\implies Mass\:of\; Reactants=Mass\:of\:Products$

$\tt:\implies 25g = 10g + x$

$\tt:\implies x = 25g - 10g$

$\underline{\boxed{\red{\tt\longmapsto Mass\:of\:B \:=\:15g}}}$

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Answer 2

Product B will weigh 15 grams.

• Law of conservation of mass states that matter can neither be created nor destroyed. This further states that mass will remain same on both sides.
• Hence, mass of 25 gram on reactant side will remain conserved as mass of 25 gram on product side.
• Let the mass of product B be x.

So, 25 = 10 + x

x = 25 - 10

x = 15 gram

• Hence, the mass of product B will be 15 gram.