Tag: law of multiple proportion

Questions Related to law of multiple proportion

A chemical equation is balanced according to the law of: 

chemistry basic concepts of chemistry law of multiple proportion law of multiple proportions laws of chemical combination

  1. multiple proportions

  2. constant proportions

  3. reciprocal proportions

  4. conservation of mass

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Correct Option: D
Explanation:
When we balance an equation, we determine the ratio of reactants to products which allows for the total number of atoms of reactants to match the number of atoms of the products.

 Since the type of atoms does not change and the number of atoms stays that same, the total mass that goes into the chemical change will match the mass that comes out after the change.

   So, law of conservation of mass is the correct answer.

Carbon and oxygen from two compounds. Carbon content in one of them is 42.9% and in the other is 27.3%. The given data is in agreement with :

chemistry basic concepts of chemistry law of multiple proportion law of multiple proportions laws of chemical combination

  1. law of conservation of mass

  2. law of multiple proportions

  3. law of reciprocal proportions

  4. law of definite proportions.

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Correct Option: B

Law of multiple proportions is illustrated by which one of the  following pairs ?

chemistry basic concepts of chemistry law of multiple proportion law of multiple proportions laws of chemical combination

  1. $H _{2}S$ and $SO _{2}$

  2. $NH _{3}$ and $NO _{2}$

  3. $N _{2}O$ and NO

  4. $N _{2}S$ and $Na _{2}O$

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Correct Option: C
Explanation:
Law of multiple proportions say that if 2 elements form more than one compounds between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers.
In $N _{2}O$ and $NO$, the ratio of weight of $N$ reacting with a constant weight of $O$ is $2:1$

State True or False.
If two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element, are in whole number ratio.

chemistry basic concepts of chemistry law of multiple proportion law of multiple proportions laws of chemical combination

  1. True

  2. False

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Correct Option: A
Explanation:

When two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element, are in whole number ratio. This is the law of multiple proportions.
Consider two elements $C$ and $O$. They combine to form $CO$ and $CO _2$.
The masses of oxygen that combine with $12$ g of carbon to form $CO$ and $CO _2$ are $16$ g and $32$ g respectively. They are in whole number ratio $1:2$.

$P _xO _y$ what will be correct value of $x$ and $y$ if $P$ and $H$ combine in the mass ratio of $3.1 : 0.3$ and in water $H$ and $O$ combine in the mass ratio $0.2 : 1.6$?

chemistry basic concepts of chemistry law of multiple proportion law of multiple proportions laws of chemical combination

  1. $1$ and $1$

  2. $1$ and $2$

  3. $2$ and $3$

  4. $2$ and $5$

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Correct Option: C
Explanation:

 

$P:H = 3.1 : 0.3 = (3.1 \times : 0.30) \times 2 = 6.2 : 0.6$

$H:O = 0.2 : 1.6 = (0.2 \times 3 : 1.6) \times 3 = 0.6 : 4.8$

$P:O = 6.2 : 4.8 = 3.1 : 2.4 $ (ratio by mass) $= 1.29: 1$

$1.29$ mass $P= 1 $ mass $O$

$x$ mass $P= 16 \ g$ mass $O$

$x= 16 \times 1.29 = 20.64 \ g$ Phosphorous

$= \cfrac {20.64}{31}$ moles Phosphorous

$= 0.66$

$1 \ mole \ O(y) = 0.66 \ mole \ P(x) = \cfrac 23$

$\therefore \ x:y = 2:3 $

$x =2 \ ; \ y=3$