Atoms and Molecules Test

Result

Atoms and Molecules Test - 38

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

Hydrogen combines with nitrogen in a 3:14 weight ratio to form ammonia. If every molecule of ammonia contains three atoms of hydrogen and one atom of nitrogen, an atom of nitrogen must weigh :

A
14 times the mass of a hydrogen atom

B
14/3 times the mass of a hydrogen atom

C
3 times the mass of a hydrogen atom

D
3/14 times the mass of a hydrogen atom

Solution

In ammonia, nitrogen and hydrogen are always present in the ratio 14:3 by mass

Let's assume mass of a Nitrogen atom is $$X$$ and that of a Hydrogen atom is $$Y$$.

From the law of constant proportion,

$$3Y:X = 3:14 \Rightarrow X=14 \times Y$$

Mass of a Nitrogen atom $$(X)$$ is 14 times that of a Hydrogen atom ($$Y$$).

Hence Option A is correct.
Question 2
1 / -0

The sum of masses of the atoms in the molecules is known as :

A
Atomic mass

B
Molecular mass

C
Gram molecular weight

D
None of the above

Solution

Molecular mass is the sum of masses of the atoms in the molecules.
Question 3
1 / -0

The weight of one molecule of a compound of molecular formula $$C_{60} H_{122}$$ is:

A
$$1.2\times 10^{-20} g$$

B
$$5.025\times 10^{-23} g$$

C
$$1.4\times 10^{-21} g$$

D
$$6.023\times 10^{-20} g$$

Solution

Weight of 1 mole of $$C_{60}H_{122} = M.W.= 60\times 12 + 122 \times 1=842$$

Number of molecules in 1 mole $$C_{60}H_{122} = 6.023 \times 10^{23}$$

Weight of one molecule $$= \dfrac {842}{6.02\times 10^{23}} gm$$

$$= 140\times 10^{-23} g = 1.4\times 10^{-21} g$$.

Hence, the correct option is $$\text{C}$$
Question 4
1 / -0

Which of the following statement is wrong?

A
An atom is electrically neutral.

B
The size of a cation is smaller than that of the corresponding atom.

C
The size of an anion is bigger than that of the corresponding atom.

D
An atom and its ion have an unequal number of protons.

Solution

An atom and its ion have an equal number of protons. Thus, for example, a chlorine atom and chloride ions have an equal number of protons.
When the chlorine atom is converted into a chloride ion, there is no change in the composition of the nucleus.
A chlorine atom has one electron less than a chloride ion. Chlorine atom gains one electron to form chloride ion.

Hence, option D is correct.
Question 5
1 / -0

Molecular mass of nitric acid is:

A
$$22\ u$$

B
$$12\ u$$

C
$$33\ u$$

D
$$63\ u$$

Solution

Molecular mass of nitric acid $$(HNO_3)$$ $$= (1 \times atomic\ mass\ of\ H) + (1 \times atomic\ mass\ of\ N) + (3 \times atomic\ mass\ of\ O)$$
$$= 1\times (1\ u) + 1\times (14\ u) + 3\times (16\ u)$$
$$= 63\ u$$
Question 6
1 / -0

Hydrogen combines with oxygen in a 1:8 weight ratio to form water. If every molecule of water contains two atoms of hydrogen and one atom of oxygen, an atom of oxygen must weigh:

A
8 times the mass of a hydrogen atom

B
16 times the mass of a hydrogen atom

C
1/16 times the mass of a hydrogen atom

D
1/8 times the mass of a hydrogen atom

Solution

The ratio of the mass of hydrogen to the mass of oxygen is always 1:8.

Let's assume the mass of an Oxygen atom is $$X$$ u and that of a Hydrogen atom is $$Y$$ u.

From the law of constant proportion,

$$2Y:X = 1:8 \Rightarrow X=16 \times Y$$

The mass of an Oxygen atom $$(X)$$ is 16 times that of a Hydrogen atom ($$Y$$).

Hence Option B is correct.
Question 7
1 / -0

1.008 grams of hydrogen combines with 35.453 g of chlorine to form 36.463 g of a pure compound (hydrogen chloride). Dalton's explanation for this experimental fact might be:

A
One atom of hydrogen combines with 35.453 atoms of chlorine in this reaction

B
Hydrogen and chlorine atoms always combine in a 1:35 ratio.

C
Chlorine accepts hydrogen's electron to form polar covalent hydrogen chloride

D
Hydrogen and chlorine atoms aren't created or destroyed in the process so the reactant mass is the same as the product mass.

Solution

Dalton Atomic theory postulates-
All matter is made up of atoms and atoms are indestructible cannot be created or destroyed so the total mass of reactants remains equal to the total mass of products.
Question 8
1 / -0

Which among the following has molecular mass of 36.5 u?

A
Carbon molecules

B
Hydrogen molecules

C
Sulphur molecules

D
Hydrochloric acid

Solution

Molar mass of Hydrochloric acid $$=1\times $$ atomic mass of $$H + 1\times$$ atomic mass of $$Cl$$
$$= 1\times (1) + 1\times (35.5)$$
$$=36.5\ u$$
Question 9
1 / -0

In the procedure shown above, a calcium chloride solution is mixed with a sodium sulfate solution to create the products shown. Which of the following is illustrated by this activity?

A
Law of conservation of mass

B
Law of definite proportions

C
Dalton's law atomic theory

D
Theory of covalent bonding

Solution

In both the diagrams mass of the reactants and products are constant. This goes with the law of conservation of mass.

Hence. option A is correct.
Question 10
1 / -0

Mass can neither be created nor destroyed. This is in agreement with which law of chemical combination?

A
Law of definite proportion

B
Law of multiple proportion

C
Law of conservation of mass

D
Law of conservation of momentum

Solution

The Law of conservation of mass states that when elements and compounds react to form new products, mass cannot be lost or gained.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Atoms and Molecules Test - 38

Result

Atoms and Molecules Test - 38

Score

-

Rank

-

SHARING IS CARING

Question 1

14 times the mass of a hydrogen atom

14/3 times the mass of a hydrogen atom

3 times the mass of a hydrogen atom

3/14 times the mass of a hydrogen atom

Solution

Question 2

Atomic mass

Molecular mass

Gram molecular weight

None of the above

Solution

Question 3

$$1.2\times 10^{-20} g$$

$$5.025\times 10^{-23} g$$

$$1.4\times 10^{-21} g$$

$$6.023\times 10^{-20} g$$

Solution

Question 4

An atom is electrically neutral.

The size of a cation is smaller than that of the corresponding atom.

The size of an anion is bigger than that of the corresponding atom.

An atom and its ion have an unequal number of protons.

Solution

Question 5

$$22\ u$$

$$12\ u$$

$$33\ u$$

$$63\ u$$

Solution

Question 6

8 times the mass of a hydrogen atom

16 times the mass of a hydrogen atom

1/16 times the mass of a hydrogen atom

1/8 times the mass of a hydrogen atom

Solution

Question 7

One atom of hydrogen combines with 35.453 atoms of chlorine in this reaction

Hydrogen and chlorine atoms always combine in a 1:35 ratio.

Chlorine accepts hydrogen's electron to form polar covalent hydrogen chloride

Hydrogen and chlorine atoms aren't created or destroyed in the process so the reactant mass is the same as the product mass.

Solution

Question 8

Carbon molecules

Hydrogen molecules

Sulphur molecules

Hydrochloric acid

Solution

Question 9

Law of conservation of mass

Law of definite proportions

Dalton's law atomic theory

Theory of covalent bonding

Solution

Question 10

Law of definite proportion

Law of multiple proportion

Law of conservation of mass

Law of conservation of momentum

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.