Tag: chemistry

Questions Related to chemistry

A hybrid rocket propellant uses:

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

  1. a liquid oxidizer and a solid fuel 

  2. a complete solid propellent

  3. a beleqiud propellent

  4. None of the above

Show answer
Correct Option: A
Explanation:
Hybrid propellant engines represent an intermediate group between solid and liquid propellant engines. One of the substances is solid, usually the fuel, while the other, usually the oxidizer, is liquid. 

The liquid is injected into the solid, whose fuel reservoir also serves as the combustion chamber. The main advantage of such engines is that they have high performance, similar to that of solid propellants, but the combustion can be moderated, stopped, or even restarted. It is difficult to make use of this concept for vary large thrusts, and thus, hybrid propellant engines are rarely built.

A hybrid engine burning nitrous oxide as the liquid oxidizer and HTPB rubber as the solid fuel powered the vehicle SpaceShipOne, which won the Ansari X-Prize.

Hence, the correct option is $\text{A}$

Which of the following pairs of compound illustrate law of multiple proportions ?

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

  1. KOH, CsOH

  2. $ H _2O, D _2O $

  3. Ethane , benzene

  4. KCI, KBr

Show answer
Correct Option: C

$i$. Percentage of $Mg$ in $MgO$ and $MgCl _{2}$ 

$ii$. Percentage of $C$ in $CO$ and $CO _{2}$
$iii$. Percentage of $Cr$ in $K _{2} Cr _{2}O _{7}$ and $K _{2}CrO _{4}$ 
$iv$. Percentage of $Cu$ isotopes in $Cu$ metal
The law of multiple proportions may be illustrated by data given by:

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

  1. $ii$

  2. $iv$

  3. $i$ and $ii $

  4. $i,\ ii$ and $iii$

Show answer
Correct Option: A
Explanation:

According to law of multiple proportion, if two elements combine to form more than one compound, then the weight of one element combining with the fixed weight of other, in the two compounds, is in a whole number ratio.

Law of multiple proportions is not applicable for the oxides (s) of __________.

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

  1. carbon

  2. iron

  3. nitrogen

  4. aluminium

Show answer
Correct Option: D
Explanation:
Law of multiple proportions

If two elements chemically combine to give two or more compounds, then the weight of one element which combines with the fixed weight of the other element in those compound bear a simple multiple ratios to one another.

Eg: Nitrogen forms the oxides- $N _2O, NO, N _2O _3, NO _2, N _2O _5$

But aluminium form only 1 type of oxide $Al _2O _3$.

The oxides of a certain (hypothetical) element contain 27.28 %, 42.86% and 52.94% oxygen. What is the ratio of the valances of the element in the 3 oxides? 

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

  1. 2 : 3 : 4

  2. 1 : 3 : 4

  3. 1 : 2 : 4

  4. 1 : 2 : 3

Show answer
Correct Option: D

$CO,CO _2, C _2O _3$ follows :

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 multiple proportion

  3. law of conservation of mass

  4. all of the above

Show answer
Correct Option: B
Explanation:

The Law of Multiple Proportion: It was given by Dalton. When one element combines with the other element to form two or more different compounds, the mass of one elements, which combines with a constant mass of the other, bear a simple ratio to one another.
So, $CO,CO _2, C _2O _3$ follows law of multiple proportion.

The composition (by atoms) of compound A is $40$% X and $60$% Y. The composition (by atoms) of compound B is $25$% X and $75$% Y. According to the law of multiple proportions, the ratio of the weight of element Y in compounds A and B is:

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

  1. $1 : 2$

  2. $2 : 1$

  3. $2 : 3$

  4. $3 : 4$

Show answer
Correct Option: A
Explanation:
The composition of compound A is  $X:Y = 40:60= 2:3$
The composition of compound B is $X:Y= 25:75= 1:3$

According to the law of multiple proportions, 
In compound A $2$ moles of $X$ bind with $3$ moles of $Y$.
In compound B $2$ moles of $X$ bind with 6 moles of $Y$ 

The ratio of the weight of element $Y$, in combining with a fixed number of $X$ atoms, in these two compounds $A$ and $B$ is $ 3:6 = 1 : 2$.

In $SO _{2}$ and $SO _{3}$, the ratio of weight of oxygen that combines with a fixed weight of sulphur is $2 : 3$. This 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. conservation of mass

  3. multiple proportions

  4. reciprocal proportions

Show answer
Correct Option: C
Explanation:

The law of multiple proportions says that If two 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.

Elements A and B combine to form three different compounds:
$0.3$ g of A $+ 0.4$ g of B $\rightarrow$ $0.7$ g of compound X
$18.0$ g of A $+\ 48.0$ g of B $\rightarrow$ $66.0$ g of compound Y
$40.0$ g of A $+\ 159.99$ g of B $\rightarrow$ $199.99$ g of compound Z
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 reciprocal proportion

  2. Law of multiple proportion

  3. Law of constant composition

  4. None of the above

Show answer
Correct Option: B
Explanation:

Weights of B that combine with $1.0$ g of A in the compounds X, Y and Z are, respectively,
$\dfrac{0.4}{0.3}=1.33,\ \dfrac{48.0}{18.0}=2.66$ and $\dfrac{159.99}{40.0}=4.00$
Ratio being $1.33:2.66:4.00$ or $1:2:3$ is the simple ratio and this illustrates the law of multiple proportions.

Different proportions of oxygen in the various oxides of nitrogen prove the law of :

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

  1. equivalent proportion

  2. multiple proportion

  3. constant proportion

  4. conservation of matter

Show answer
Correct Option: B
Explanation:

Different proportions of oxygen in the various oxides of nitrogen prove the law of multiple proportions.
According to the law of multiple proportions,
 "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".

Example.
14 g of nitrogen combine with 16  g of oxygen to form 30 g of $NO$.
The ratio of masses $N:O$ is $14:16$.

14 g of nitrogen combine with 32  g of oxygen to form 46 g of $NO _2$.
The ratio of masses $N:O$ is $14:32$.

The two ratios are in the proportion of $32:16=2:1$.