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Questions Related to chemistry

$3.2$ g sulphur combines with $3.2$ g of oxygen to form a compound in one set of conditions. In another set of conditions, $0.8$ g of sulphur combines with $1.2$ g of oxygen to form another compound. State the law illustrated by these chemical combinations.

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

  1. Law of constant composition

  2. Law of reciprocal proportion

  3. Law of multiple proportion

  4. None of the above

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Correct Option: C
Explanation:

First case,
$3.2$ g of S combines with $3.2$ g of $O _2$.
$1$ g of S combines with $1$ g of $O _2$.
Second case,
$0.8$ g of S combines with $1.2$ g of $O _2$
$1$ g of S combines with $\dfrac {1.2}{0.8}=1.5$ g of $O _2$
Thus, the ratio of the $O _2$ in both cases which combines with a fixed mass ($1$ g) of $S=1:1.5$ or $2:3$, which is a simple whole number ratio and hence, the law of multiple proportion is verified.

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

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

  1. $HCl$ and $HNO _{3}$

  2. $KOH$ and $KCl$

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

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

Show answer
Correct Option: C
Explanation:

A fixed mass of nitrogen, say $100$ grams, may react with $57.14$ grams of oxygen to produce one oxide, or with $114.28$ grams of oxygen to produce the other. The ratio of the masses of oxygen that can react with $100$ grams of nitrogen is $57.14:114.28$ or  $2:1$, a ratio of small whole numbers.

Hydrogen peroxide and water contain $5.93$% and $11.2$% of hydrogen respectively. The data illustrates the law of:

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

  1. constant proportions

  2. multiple proportions

  3. reciprocal proportions

  4. conservation of mass

Show answer
Correct Option: B
Explanation:

For hydrogen peroxide, 100 g of sample will contain 5.93 g hydrogen and  $\displaystyle 100 - 5.93 = 94.07$ g oxygen respectively.

The ratio of the mass of oxygen to the mass of hydrogen in hydrogen peroxide is  $\displaystyle \dfrac {94.07}{5.93} = 15.86$

For water, 100 g of sample will contain 11.2 g hydrogen and  $\displaystyle 100 - 11.2 = 88.8$ g oxygen respectively.

The ratio of the mass of oxygen to the mass of hydrogen in hydrogen peroxide is  $\displaystyle \dfrac {88.8}{11.2} = 7.93$

The two ratios are in the proportion $\displaystyle \dfrac {15.86}{7.93} = 2:1$

Hence, this illustrates the Law of multiple proportions. According to this law, if two elements chemically combine with each other forming two or more compounds with different compositions by mass then the ratios of masses of two interacting elements in the two compounds are small whole numbers.

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

Color % Ms (by mass) % O (by mass)
Oxide # $1$Oxide # $2$ BlackDk Green $63.19$$77.50$ $36.81$$22.50$

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

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

The molecules of nitrogen monoxide and nitrogen dioxide differ by a multiple of the mass of one oxygen. The statement can be understood by the concept of :

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

  1. Law of multiple proportion

  2. Nuclear fusion

  3. Van dar Waals forces

  4. Graham's Law of Diffusion(Effusion)

  5. Triple point

Show answer
Correct Option: A
Explanation:

The molecules of nitrogen monoxide and nitrogen dioxide differ by a multiple of the mass of one oxygen. The statement can be understood by the concept of the Law of multiple proportion.

Which of the following pairs of compounds can be used to illustrate Dalton's Law of Multiple Proportions?

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

  1. $NH _{4}$ and $NH _{4}Cl$

  2. $SO _{2}$ and $SO _{3}$

  3. $H _{2}$ and $O _{2}$

  4. $H _{2}O$ and $HCl$

Show answer
Correct Option: B
Explanation:

Law of Multiple proportions states that if two elements form more than one compound between them, then the ratios of masses of second element which combine with a fixed mass of first element ratios of small whole numbers.

$*$ Ex: 1) $CO, CO _2$           2) $SO _2, SO _3$           3)$CuO, Cu _2O$ etc.

$CaCO _3 + 2HCl \rightarrow CaCl _2 + H _2O + CO _2$

The mass of calcium chloride formed when 2.5 g of calcium carbonate is dissolved in excess of hydrochloric acid is:

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

  1. 1.39 g

  2. 2.78 g

  3. 5.18 g

  4. 17.8 g

Show answer
Correct Option: B
Explanation:

CaCO3 + 2HCl -----> CaCl2 + H2O + CO2. 
2.5g? g 
Mass of CaCO3= 40+12+3(16)=52+ 48= 100. 
Molar mass of CaCO3=100g. 
Mass of CaCl2= 40 + 2(35.5)= 40+ 71= 111. 
Molar mass of CaCl2=111g. 
Mass of CaCO3 (g) Mass of CaCl2 (g) 
For 100g of $CaCO _3$, 111g of CaCl_2$ is formed.
let for 2.5g of $CaCO_3$, $x$ g of $CaCl_2$ is formed.
Thus, by cross multiplication,

$x=111\times 2.5/100= 2.775g = 2.78g$.

For describing law of multiple proportions, which among the following pair can be used?

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

  1. NO and $NO _2$

  2. $CH _4$ and $CO _2$

  3. $ZnO _2$ and $ZnCl _2$

  4. $NH _3$ and $NH _4Cl$

  5. $H _2O$ and HCl

Show answer
Correct Option: A
Explanation:

For describing law of multiple proportions, the pair $\displaystyle  NO$ and $\displaystyle  NO _2$ can be used.
According to the law of multiple proportions, if two elements combine to form more than one compound, then the different masses of one element which combine with fixed mass of other element, bear a simple ratio to one another.
In the pair $\displaystyle  NO$ and $\displaystyle  NO _2$, we have two elements N and O that combine to form more than one compound. In all other examples, more than two elements are present.

A metal forms two oxides with first oxide having 1 and second having 3 oxygen atoms and their masses are 74g and 164 g respectively. If the gram atomic mass of oxygen is 16g, do both compounds follow the law of multiple proportions?

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

The law of the multiple proportion was proposed by:

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

  1. Dalton

  2. Dulong

  3. Petit

  4. Lavoisier

Show answer
Correct Option: A
Explanation:

The law of the multiple proportion was proposed by Dalton.
Law of multiple proportions, statement that when two elements combine with each other to form more than one compound, the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.