Atoms and Molecules Test

Result

Atoms and Molecules Test - 58

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

In an experiment, $$2.4\ g$$ of iron oxide on reduction with hydrogen gave $$1.68\ g$$ of iron. In another experiment, $$2.69\ g$$ of iron oxide gave $$1.88 \ g$$ of iron on reduction. Which law is illustrated from the above data?

A
Law of constant proportions

B
Law of multiple proportions

C
Law of reciprocal proportions

D
Law of conservation of mass

Solution

In the first experiment,
$$2.4\ g$$ of iron oxide gave $$1.68\ g$$ of iron.
Mass of iron oxide $$=2.4\ g$$
Mass of iron $$=1.68\ g$$

$$\therefore$$ Mass of oxygen $$=2.4-1.68=0.72$$
The ratio of masses of iron and oxygen $$=\dfrac{1.68}{0.72}=7:3$$

In the second experiment,
Mass of iron oxide $$=2.69\ g$$
Mass of iron $$=1.88\ g$$
Mass of oxygen $$=2.69-1.88=0.81$$
The ratio of masses of iron and oxygen $$=\dfrac{1.88}{0.81}=7:3$$
The same ratio confirms that these experiments clarify Law of constant proportion.
Hence, option $$A$$ is correct.
Question 2
1 / -0

Which of the following correctly represents 180 g of water?
(i) 5 moles of water
(ii) 10 moles of water
(iii) $$6.023 \times 10^{23}$$ molecules of water
(iv) $$6.023 \times 10^{24}$$ molecules of water

A
(i)

B
(ii)

C
(iii)

D
(iv)

Solution

$$18\ g$$ of $$H_2O=1$$ mol
$$180\ g$$ of $$H_2O=10$$ mol
$$18\ g$$ of $$H_2O=6.023\times 10^{23}$$ molecules of $$H_2O$$
$$180\ g$$ of $$H_2O=\dfrac {6.023\times 10^{23}}{18}\times 180$$
$$=6.023\times 10^{24}$$ molecules of $$H_2O$$
Question 3
1 / -0

The mass of one mole of a substance in gram is called its:

A
molecular mass

B
molar mass

C
Avogadro's mass

D
formula mass

Solution

The mass of one mole of a substance in a gram is called its molar mass.
Hence, option $$B$$ is correct.
Question 4
1 / -0

If water samples taken from the sea, rivers, lakes or snow-capped mountains, are found to contain hydrogen and oxygen in the ratio of $$1: 8$$. This demonstrates:

A
The law of chemical equilibrium

B
The law of definite proportions

C
Avogadro's law

D
The modern periodic law

Solution

The law of definite proportion states that a given chemical compound always contains its component elements in a fixed ratio (by mass) and this ratio does not change if we change the source or method of preparation. In all the water samples, taken from the sea, rivers, lakes or snow-capped mountains, the hydrogen and oxygen ratio is constant, clearly demonstrating the law of definite proportions.
Question 5
1 / -0

An atom can be smashed and broken into many nuclear particles by the high acceleration (increasing speed) imparted in:

A
a chromatograph

B
a cyclotron

C
an electron microscope

D
acathode-ray tube

Solution

Cyclotron also known as particle accelerator which works on the principle of perpendicular magnetic and electric field.
If can smashed and broken into many nuclear particle.
Question 6
1 / -0

Which of the following statements is incorrect?

A
One gram atom of carbon contains Avogadro's number of atoms.

B
One mole of oxygen gas contains Avogadro's number of molecules.

C
One mole of hydrogen gas contains Avogadro's number of atoms.

D
One mole of electrons stands for $$6.02\times{10}^{23}$$ electrons.

Solution

1 mole of any substance in a monovalent state has Avogadro's number of atoms in it which implies 1 mole of H has $$6.022 \times {10}^{23}$$ of atoms in it.

Since $${H}_{2}$$ gas has 2 hydrogen atoms in it, thus contains twice Avogadro's number of atoms.

Thus, 1 Mole of $${H}_{2} = 2 \times \text{Avogadro's number} = 2 \times 6.022 \times {10}^{23} = 12.044 \times {10}^{23}$$.

One gram atom means 1 mole hence one gram atom of carbon contains one mole of carbon i.e Avogadro's number of atoms.
One molle of oxygen gas contains, Avogadro's number of molecules but twice the number of oxygen atoms as it exists as $$O_2$$.
One mole of electrons means Avogadro's number of electrons or $$6.022 \times 10^{23}$$ electrons.
Question 7
1 / -0

The number of atoms present in $$16g$$ of oxygen is:

A
$$6.02\times { 10 }^{ 15 }$$

B
$$3.01\times { 10 }^{ 23 }$$

C
$$3.01\times { 10 }^{ 15 }$$

D
$$6.02\times { 10 }^{ 23 }$$

Solution

1 mole of oxygen$$=16g$$

1 mole of oxygen contains$$=6.022\times { 10 }^{ 23 }\quad atoms$$

$$\therefore $$ $$16$$ of oxygen$$=6.022\times { 10 }^{ 23 }\quad atoms$$

Answer will be $$\left( D \right) $$
Question 8
1 / -0

The density of a gaseous substance at 1 atm pressure and 773 K is 0.4g/lit. If the molecular weight of the substance is 30 the forces existing among gas molecules are?

A
repulsive

B
attractive

C
both

D
none

Solution

$$PV = ZnRT$$ or $$PM = ZdRT$$ ($$M =$$ molecular weight)

Now put all the given value

$$(1)(30) = z(0.4)(0.082)(773)$$
$$z=0.074 < 1$$, thus forces are attractive.

Hence, option $$B$$ is the correct answer.
Question 9
1 / -0

$$0.1g \ CaCO_3$$ will contain:

A
$$0.1 N_A \ Ca^{2-}\ ion$$

B
$$0.01N_A \ Ca^{2+} \ ion$$

C
$$0.001 N_A \ Ca^{2+}\ ion$$

D
$$N_A\ Ca^{2+}\ ion$$

Solution

$$ CaCO_3 \longrightarrow Ca^{2+} + CO_3^{2-}$$

$$n$$ mole of $$CaCO_3$$ will give $$n$$ mole of $$Ca^{2+}$$ ion.

So Mole of $$CaCO_3$$ = Mole of $$Ca^{2+}$$

$$\Rightarrow\dfrac{Given \ mass}{Molar \ mass} = $$ Moles of $$Ca^{2+}$$

$$\Rightarrow\dfrac{.1}{100} =$$ Mole of $$Ca^{2+}$$

$$\therefore$$ Moles of $$Ca^{2+} = 0.001 \ mole$$

Number of ions = $$N_A\times moles$$
Number of ions = $$N_A\times .001$$
Hence, option $$C$$ is correct.
Question 10
1 / -0

What mass of sodium chloride will react with 34.0 g of silver nitrate to produce 17 g of sodium nitrate and 28.70 g of silver chloride if the law of conservation of mass holds good ?

A
12.35 grams

B
11.70 grams

C
9.32 grams

D
None of these

Solution

$$Nacl + AgNO_{3} \rightarrow NaNO_{3}+Agcl$$
By law of conservation of max
total mass on left
By law of conservation of mass
total mass on right
$$ \Rightarrow x+ 3y = 17+28.7 $$
$$ \boxed{x = 11.70 gm}$$

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Atoms and Molecules Test - 58

Result

Atoms and Molecules Test - 58

Score

-

Rank

-

SHARING IS CARING

Question 1

Law of constant proportions

Law of multiple proportions

Law of reciprocal proportions

Law of conservation of mass

Solution

Question 2

(i)

(ii)

(iii)

(iv)

Solution

Question 3

molecular mass

molar mass

Avogadro's mass

formula mass

Solution

Question 4

The law of chemical equilibrium

The law of definite proportions

Avogadro's law

The modern periodic law

Solution

Question 5

a chromatograph

a cyclotron

an electron microscope

acathode-ray tube

Solution

Question 6

One gram atom of carbon contains Avogadro's number of atoms.

One mole of oxygen gas contains Avogadro's number of molecules.

One mole of hydrogen gas contains Avogadro's number of atoms.

One mole of electrons stands for $$6.02\times{10}^{23}$$ electrons.

Solution

Question 7

$$6.02\times { 10 }^{ 15 }$$

$$3.01\times { 10 }^{ 23 }$$

$$3.01\times { 10 }^{ 15 }$$

$$6.02\times { 10 }^{ 23 }$$

Solution

Question 8

repulsive

attractive

both

none

Solution

Question 9

$$0.1 N_A \ Ca^{2-}\ ion$$

$$0.01N_A \ Ca^{2+} \ ion$$

$$0.001 N_A \ Ca^{2+}\ ion$$

$$N_A\ Ca^{2+}\ ion$$

Solution

Question 10

12.35 grams

11.70 grams

9.32 grams

None of these

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.