Tag: chemistry

Questions Related to chemistry

Hydrogen and oxygen forms two compounds. The hydrogen content in these compounds is 42.9% and 27.3%. These compounds follow which law ?

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

  1. Law of definite proportion

  2. Law of reciprocal proportion

  3. Law of multiple proportion

  4. Law of combining volumes

Show answer
Correct Option: C
Explanation:

The law of multiple proportions state that if two elements form more than one compound 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.

The chloride of a solid metallic element contains 57.89% by mass of the element. The specific heat of the element is $0.0324\, cal\, deg^{-1}\, g^{-1}$. Calculate the exact atomic mass of the clement. 

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

  1. 195.2

  2. 195

  3. 195.9

  4. 194

Show answer
Correct Option: A
Explanation:
% of element is given in this question = 57.89
so %  of chlorine is = 100-57.89 = 42.11

Equivalent wt of metal= $\dfrac{57.89}{42.11} \times 35.5$ = 48.8

specific heat of metal= 0.0324

$\rightarrow $ According to Dulong and Petit's law
Approx atomic wt of metal= $\dfrac{6.4}{ specific heat} = \dfrac{6.4}{0.0324}$ = 197.53

Valency of metal= Approximate atomic wt/ Equivalent wt

 = $\dfrac{197.53}{ 48.8}$ = 4.04  = 4

Exact atomic wt of metal = $ Equivalent wt of metal\times Valency of metal$ = 48.8 x 4
  = 195.2
answer is A

Two different oxides of manganese are compared in the table shown below.

Color % Mn (by mass) % O (by mass)
Oxide # $1$ Black $63.19$ $36.81$
Oxide # $2$ Dk Green $77.50$ $22.50$

When substituted for X and Y in the fraction below, which pair CORRECTLY gives a result that illustrates the Law of Multiple Proportions?
$63.19$
$\overline {X}$
$\overline {77.50}$
$\overline {Y}$

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

  1. $X = 54.94$

    $Y = 54.94$

  2. $X = 36.81$

    $Y = 22.50$

  3. $X = 16.00$

    $Y = 16.00$

  4. $X = 22.50$

    $Y = 36.81$

Show answer
Correct Option: A

Which of the following pairs illustrates the law of multiple proportions?

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

  1. $PH _3$, $HCl$

  2. $PbO$, $PbO _2$

  3. $H _2S$, $SO _2$

  4. $CuCl _2$, $CuSO _4$

Show answer
Correct Option: B
Explanation:

the law of multiple proportions.: two elements combine to form more than one compound and the masses of one element that combine with a fixed mass of the other element is in the ratio of small whole numbers. 

So all elements are same only the mass ratio of reactants varies the product formation.
thus in $PbO$ and $PbO _2$ the reactants are $Pb$ and $O _2$ that combine in different ratio. other options do not have all the elements common.
option B is correct

Which of the following statements illustrates the law of multiple proportions?

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

  1. An element forms two oxides, XO and $XO _2$ containing $50\%$ and $60\%$ oxygen respectively. The ratio of masses of oxygen which combines with 1 g of element is 2:3

  2. Hydrogen sulphide contains $5.89\%$ hydrogen, water contains $11.1\%$ hydrogen and sulphur dioxide contains $50\%$ oxygen.

  3. 3.47 g of $BaCl _2$ reacts with 2.36 g of $Na _2SO _4$ to give 3.88 g of $BaSO _4$ and 1.95 g of NaCl.

  4. 20 mL of ammonia gives 10 volumes of $N _2$ and 30 volumes of $H _2$ at constant temperature and pressure

Show answer
Correct Option: A
Explanation:
Law of multiple proportions states that when two elements combine to form two or more compounds, the masses of one element which combine with the fixed mass of another element, will always be in ratio of whole numbers.
The statement is :
An element forms two oxides $XO$ and ${ XO } _{ 2 }$ containing $50$% and $60$% of oxygen respectively. The ratio of masses of ${ O } _{ 2 }$ which combine with $1g$ of element of $2:3$.

In compound A, 1.0 g nitrogen combines with 0.57 g oxygen. In compound B, 2.0 g nitrogen unite with 2.24 g oxygen and in compound C, 3.0 g nitrogen combine with 5.11 g oxygen. These results obey 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. none of these

Show answer
Correct Option: A
Explanation:

In compound A 1 gm of nitrogen combined with 0.57 gm of oxygen and compound B 1 gm of nitrogen combined with 1.12 gm of oxygen and C 1 gm of nitrogen combined with 1.7 gm of oxygen so the fixed amount of nitrogen is 1: 2 :3 so this follows of multiple proportion rule 

Carbon and oxygen form 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

Show answer
Correct Option: B
Explanation:

The given data is in agreement with Law of multiple proportions.

The Law of multiple proportions states that the masses of one element combine with a fixed mass of the second element are in a ratio of whole numbers.
In $100$ $g$ of the first compound $O:C=$$57$ $/42.9$ $=1.33$  
In $100$ $g$ of the second compound $O:C=$$72.7$ $/27.3$ $=2.66$  
Ratio $=2.66:1.33=2:1$
This whole number ratio is consistent with Law of multiple proportions. 

$12g$ of carbon combines with $64g$ sulphur to form ${CS} _{2}$. $12g$ carbon also combines with $32g$ oxygen to form ${CO} _{2}$. $10g$ sulphur combines with $10g$ oxygen to form ${SO} _{2}$. These data illustrate the

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

  1. Law of multiple proportions

  2. Law of definite proportions

  3. Law of reciprocal proportions

  4. Law of gaseous volumes

Show answer
Correct Option: C
Explanation:

Given,

$12g$ $C$ combines with $64g$ $S$ to give $CS _2$
$12g$ $C$ combines with $32g$ $O$ to give $CO _2$
Also, $10gS$ combines with $10gO$ to give $SO _2$
In $CS _2$ $C:S=12:64=3:16$
In $CO _2$ $C:O=12:32=3:8$
From, $CS _2$ & $CO _2$, $S:O=16:8=2:1$
Also in $SO _2$ $S:O=10:10=1:1$
$\Rightarrow 2:1$ is multiple of $1:1$
$\cfrac {1}{1}\times 2=\cfrac {2}{1}$
$\Rightarrow $ Law of reciprocal proportions is illustrated here.

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

Show answer
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.

Show answer
Correct Option: B