Some Basic Concepts of Chemistry Test

Result

Some Basic Concepts of Chemistry Test - 44

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

Who supported the Four Element Concept of Empedocles?

A
Dalton

B
Avogadro

C
Einstein

D
Aristotle

Solution

The four Element concept was supported by Aristotle.
The theory suggests that there were four elements that everything was made up of: earth, water, air and fire.
Question 2
1 / -0

Radioactivity is the caused by the disintegration of:

A
Atom

B
Ion

C
Molecule

D
Nucleus

Solution

Radioactive decay (also known as nuclear decay or radioactivity) is the process by which the nucleus of an unstable atom loses energy by emitting radiation, including alpha particles, beta particles, gamma rays, and conversion electrons. A material that spontaneously emits such radiation is considered radioactive.
Question 3
1 / -0

A compound $$X_2O_3$$ contains 31.58% oxygen by weight. The atomic weight of $$X$$ is:

A
$$344.66 g/mol$$

B
$$52.00 g/mol$$

C
$$45.01 g/mol$$

D
$$104.0 g/mol$$

Solution

Let $$x$$ g/mol be the atomic weight of $$X$$. The atomic weight of $$\displaystyle O = 16$$ g/mol. The molecular weight of $$\displaystyle X_2O_3 = 2(x)+3(16)=2x+48$$ g/mol

Weight percent of $$\displaystyle O = \dfrac {3(16)}{2x+48} \times 100= 31.58$$

$$\displaystyle \dfrac {48}{2x+48} = 0.3158 $$

$$\displaystyle 2x+48 = \dfrac {48}{0.3158} $$

$$\displaystyle 2x+48=151.9$$

$$\displaystyle 2x=103.9$$

$$\displaystyle x=52.00$$ g/mol.

Hence, the atomic weight of $$X$$ is $$52.00 g/mol.$$

So, option (B) is the correct answer.
Question 4
1 / -0

At room temperature and pressure, two flasks of equal volumes are filled with $$H_2$$ and $$SO_2$$ separately. Particles which are equal in number, in the two flasks are:

A
atoms

B
electrons

C
molecules

D
neutrons

Solution

At a given volume at constant temperature and pressure, two gases have equal no. of moles
hence, the no. of molecules will be same in both flasks.
Question 5
1 / -0

What is the mass of one molecule of yellow phosphorus?

[Atomic mass, P = 30]

A
$$1.993 \times 10^{22}$$ mg

B
$$1.993 \times 10^{-19}$$ mg

C
$$4.983 \times 10^{-20}$$ mg

D
$$4.983 \times 10^{-23}$$ mg

Solution

Yellow phosphorus$$ (P_4)$$ exists as molecules made up of four atoms in a tetrahedral structure.

Mass of one mole of yellow phosphorous is $$4\times 30=120\ g$$

1 mole has $$6.032\times 10^{23}$$ molecules.

So mass of one molecule will be $$\dfrac { 120 }{ 6.023\times{ 10 }^{ 23 } } g=19.93\times10^{-23}g=1.993\times10^{-19}mg$$

Hence, option B is correct.
Question 6
1 / -0

$$SO_2$$ gas was prepared by
(i) burning sulphur in oxygen,
(ii) reacting sodium sulphite with dilute $$H_2SO_4$$ and
(iii) heating copper with $$conc. H_2SO_4$$. It was found that in each case sulphur and oxygen combined in the ratio of 1 : 1. The data illustrates the law of :

A
conservation of mass

B
multiple proportions

C
constant proportions

D
reciprocal proportions

Solution

Ratio of sulfur & oxygen $$=1:1.$$
Thus illustrates law of constant proportions because the ratio is a constant.
Question 7
1 / -0

2.0 g mixture of sodium carbonate and sodium bicarbonate on heating to constant mass gave 224 mL of $$CO_2$$ at NTP. The % mass of sodium bicarbonate in the mixture is:

A
50

B
54

C
80

D
84

Solution

Sodium bicarbonate decomposes in
the following manner.
$$ 2NaHCO_{3}\rightarrow Na_{2}CO_{3}+H_{2}O+CO_{2} $$
Sodium Carbonate is stable and
doesn't dissociate upon normal
heating.
Vol. of $$ CO_{2} = 224\,ml $$
$$ 22.4\,Ltr = 1\,mole $$
So moles of $$ CO_{2} = 0.224/22.4 = 0.01\,mole $$
$$ 0.01\,mole = 44\times 0.01\,g = 0.44\,g $$
1 mole $$ CO_{2} $$ is procured by 2 mole $$ NaHCO_{3} $$
$$ \therefore $$ Moles of $$ NaHCO_{3} = 2\times 0.01 = 0.02 $$
$$ = 0.02\times 84 = 1.689 $$
$$\% $$ age $$ = \dfrac{mass}{Total\,mass}\times 100 = \dfrac{1.68}{2}\times 100 = 84\% $$
Question 8
1 / -0

Cations absorb $$6.023\times 10^{22}$$ electrons for their reduction. How many equivalents of the ion are reduced?

A
$$0.1$$

B
$$0.01$$

C
$$0.001$$

D
$$0.0001$$

Solution

1 equivalent of ion absorbs 6. 023 $$\times 10^{23}$$ electrons
No. of equivalents reduced = $$\dfrac{6.023\times 10^{22}}{6.023 \times 10^{23}}$$= 0.1
Question 9
1 / -0

The father of modern chemistry is:

A
Priestley

B
Lavoisier

C
Dalton

D
Mendeleev

Solution

Antoine Lavoisier is known as the father of modern chemistry. Lavoisier wrote the book "Elements of Chemistry" (1787). He compiled the first complete (at that time) list of elements, discovered and named oxygen and hydrogen, helped develop the metric system, helped revise and standardize chemical nomenclature, and discovered that matter retains its mass even when it changes forms.

Hence, the correct option is $$B$$
Question 10
1 / -0

Hydrogen combines with chlorine to form HCI. It also combines with sodium to form NaH. If sodium and chlorine also combine with each other, they will do so in the ratio of their masses as:

A
23 : 35.5

B
35.5 :23

C
1 : 1

D
23 : 1

Solution

Since, mass ratio of $$ H : Cl = 1 : 35.5$$ in HCl and $$Na : H = 23 : 1$$ in NaH.
And since according to law of constant proportion compounds always contains its elements in a fixed ratio by mass.
So, for$$\text{ 1gm of H}$$ we are having$$\text{ 35.5gm Cl and 23gm Na.}$$
Hence, the ratio $$Na : Cl = 23 : 35.5$$.
Hence, the answer is option A.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Some Basic Concepts of Chemistry Test - 44

Result

Some Basic Concepts of Chemistry Test - 44

Score

-

Rank

-

SHARING IS CARING

Question 1

Dalton

Avogadro

Einstein

Aristotle

Solution

Question 2

Atom

Ion

Molecule

Nucleus

Solution

Question 3

$$344.66 g/mol$$

$$52.00 g/mol$$

$$45.01 g/mol$$

$$104.0 g/mol$$

Solution

Question 4

atoms

electrons

molecules

neutrons

Solution

Question 5

$$1.993 \times 10^{22}$$ mg

$$1.993 \times 10^{-19}$$ mg

$$4.983 \times 10^{-20}$$ mg

$$4.983 \times 10^{-23}$$ mg

Solution

Question 6

conservation of mass

multiple proportions

constant proportions

reciprocal proportions

Solution

Question 7

50

54

80

84

Solution

Question 8

$$0.1$$

$$0.01$$

$$0.001$$

$$0.0001$$

Solution

Question 9

Priestley

Lavoisier

Dalton

Mendeleev

Solution

Question 10

23 : 35.5

35.5 :23

1 : 1

23 : 1

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.