Laws of Chemical Combination

Q.

According to __________, during a chemical reaction, the total mass of the products remains equal to that of reactants

1. law of multiple proportions

2. law of constant proportions

3. avogadro's law

4. law of conservation of mass

Q.

State the law of constant proportions. Give one example to illustrate this law.

Q.

The law of conservation of mass states that during a chemical reaction the total mass of the reactants must not be equal to the total mass of the products.

1. True
2. False

Q. A : Carbon combines with $\frac{4}{3}$ times its mass of oxygen in carbon monoxide.

A : कार्बन मोनोऑक्साइड में कार्बन अपने द्रव्यमान के $\frac{4}{3}$ गुने ऑक्सीजन के द्रव्यमान के साथ संयोग करता है।

R : 14 g of carbon combines with 13 g of oxygen to form carbon monoxide.

R : 14 g कार्बन 13 g ऑक्सीजन के साथ संयोग करके कार्बन मोनोऑक्साइड बनाता है।

1. Both (A) and (R) are true and (R) is the correct explanation of (A)
   
   (A) तथा (R) दोनों सही हैं तथा (R), (A) का सही स्पष्टीकरण है
2. Both (A) and (R) are true but (R) is not the correct explanation of (A)
   
   (A) तथा (R) दोनों सही हैं लेकिन (R), (A) का सही स्पष्टीकरण नहीं है
3. (A) is true but (R) is false
   
   (A) सही है लेकिन (R) गलत है
4. (A) is false but (R) is true
   
   (A) गलत है लेकिन (R) सही है

Q.

5 grams of compound A reacts with 10 grams of compound B to produce a new compound C. What should be the mass of C according to law of conservation of mass?

1. 5 g

2. 50 g

3. 15 g

4. 10 g

Q.

Why is the weight of product greater than the reactants when the reactants are burnt ??

Q.

During a physical change or chemical change, the total mass of the products remains equal to the total mass of reactants. Which of the following law states that?

1. Gay lussac law.

2. Law of conservation of mass.

3. Avogadro law

4. Law of Multiple proportions.

Q.

State law of constant proportions.

Q. How much amount of hydrogen (in g) is required to react with 36 g of carbon to form methane $\left({\text{CH}}_4\right)$?

1. 12

Q.

_________ is neither created nor destroyed during a chemical reaction.

Q. Which of the following is correct for the 'Law of Conservation of Mass'?

1. Mass can neither be created nor destroyed.
2. The elements are always present in a constant proportion in a chemical substance.
3. The rate of reaction is directly proportional to the active mass of the reactants.
4. Mass can either be created or destroyed in a chemical reaction.

Q.

Law of constant proportion states that:

In a chemical substance the elements are NOT present in a definite proportion by mass.

1. True

2. False

Q.

State and explain the law of constant proportions by giving an example.

Q.

If we rub a plastic comb on dry hair for some time and bring this comb near small pieces of paper, it attracts small pieces of paper. Which of the following can be related to this?

1. Atoms are indivisible

2. Atoms are divisible

3. Atoms repel each other

4. Atoms can attract each other

Q.

In law of constant proportion, the word constant means that the mass ratio of the elements in a chemical compound will always remain same.

1. True

2. False

Q. Assertion :Pure water obtained from different sources such as river, well, spring, sea etc. always contain hydrogen and oxygen combined in the ratio $1:8$ by mass. Reason: A chemical compound always contains elements combined together in same proportion by mass, it was discovered by French chemist, Joseph Proust (1799).

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is incorrect but Reason is correct

Q. Statement 1: In a chemical reaction, the mass of the reactants is equal to the mass of the products.
Statement 2: Chemical reactions involve only the rearrangement of atoms.

Q. Statement 1: In a chemical reaction, the mass of the reactants is equal to the mass of the products.
Statement 2: Chemical reactions involve only the rearrangement of atoms.

1. Both statements 1 and 2 are false
2. Statement 1 is false and statement 2 is true
3. Both statements 1 and 2 are true
4. Statement 1 is true and statement 2 is false

Q.

In a chemical reaction, the total mass of reactants is........................................................................... (equal to/more than) the total mass of the products.

Q. Irrespective of the source, a pure sample of water always yields $88.89\%$ oxygen by mass and $11.11\%$ hydrogen by mass. This is explained by the law of:

1. none of these
2. conservation of mass
3. constant proportion
4. multiple proportion

Q. What is the mass in grams of $6.022\times {10}^{23}$ atoms of oxygen?

1. 16
2. 32
3. 4
4. 8

Q.

Define the law of conservation of mass. How is it applicable to chemical reaction.

Q.

According to the law of conservation of mass, what would be the number of $H_2$ molecule in $N_2+H_2\to N{H}_3$ ?

1. 2

2. 3

3. 4

4. 1

Q.

When $3\mathrm{g}$ of carbon is burnt in $8\mathrm{g}$ of oxygen, $11\mathrm{g}$ of Carbon dioxide is produced. What mass of Carbon dioxide will be formed when $3\mathrm{g}$ of carbon is burnt in $50\mathrm{g}$ of oxygen? Show that the data is in accordance with the law of constant proportion.

Q.

The distinction between atoms and molecules was made by:

1. Laws of chemical combination

2. Avogadro law

3. Gay lussacs law

4. Dalton's atomic theory

Q. g of hydrogen is required to completely react with 36 grams of carbon to form methane (${\text{CH}}_4$).

1. 12
2. 24
3. 72
4. 108

Q. All samples of carbon dioxide contain carbon and oxygen in the mass ratio of $3:8$. This is in agreement with the law of :

1. conservation of mass
2. constant proportion
3. multiple proportions
4. gaseous volumes

Q. What would be the mass of Z formed when, 5 g of X reacts with 6 g of Y?

X+Y→Z

1. 11

Q.

The mass ratio of carbon to hydrogen in methane is 3:1. How much amount of hydrogen is required to react with 36 g of carbon to form methane?

1. 10 gm

2. 12 gm

3. 30 gm

4. 16 gm

Q.

During a physical change or chemical change, the total mass of the products remains equal to the total mass of reactants. Which of the following law states that?

1. Law of conservation of mass

2. Gay lussac law

3. Law of Multiple proportions

4. Avogadro law