Atoms and Molecules Test

Result

Atoms and Molecules Test - 34

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

Which of the following is not a compound?

A
Oxygen

B
Water

C
Sugar

D
Common salt

Solution

Oxygen is an element and not a compound as its molecule is made up of only one kind of atom, $$O_2$$. Whereas, water($$H_2O$$), sugar($$C_{12}H_{22}O_{11}$$) and common salt ($$NaCl$$), are all made up of two more different kinds of atoms, hence they are all known as compounds.
So, option A is correct.
Question 2
1 / -0

.............. is the smallest unit of an element that maintains the properties of that element.

A
electron

B
atom

C
proton

D
ions

Solution

An atom is the smallest particle which consists of electros, protons and neutrons in it.
$$\therefore$$ Option $$B$$ is correct.
Question 3
1 / -0

Calculate the molecular mass of $$H_2O$$ (Water)

A
$$18$$

B
$$36$$

C
$$20$$

D
$$16$$

Solution

Molecular mass of $$H_2O$$ is $${2+16=18}$$
$$\therefore$$ Option $$A$$ is correct.
Question 4
1 / -0

An atom which is deficient of electrons is called a ________ .

A
positive ion

B
proton

C
negative ion

D
none of these

Solution

Basically, an atom is electrically neutral. In case, if the atom loses an electron then there will be an extra proton in comparison to the number of electrons, hence the atom will gain a positive charge, hence will be called a positive ion.
Question 5
1 / -0

Molecules are the components of:

A
Solutions

B
Gases

C
Solids

D
All of the above

Solution

Molecules are the group of atoms bonded together, which make up different matter. Hence, all the above options will have molecules.
Question 6
1 / -0

When hydrogen and oxygen combine to form water, they form:

A
an unstable compound

B
a stable mixture

C
an unstable mixture

D
an extremely stable compound

Solution

When hydrogen and oxygen combine to form water, they form water an extremely stable compound. We can say water is a stable compound because tremendous energy is released is a signal that it is very hard to break water molecules into the original components.

$$2H_2+O_2\longrightarrow 2H_2O$$
Question 7
1 / -0

3 g of a hydrocarbon on combustion in excess of oxygen produces 8.8 g of $$CO_2$$ and 5.4 g of $$H_2O$$.

The data illustrates the law of :

A
Conservation of mass

B
Multiple proportions

C
Constant proportions

D
None of the above

Solution

Mass of carbon in 8.8 g $$CO_2 = \dfrac {12}{44} \times 8.8 = 2.4 \ g$$

Mass of hydrogen in 5.4 g $$H_2O = \dfrac{2}{18} \times5.4 = 0.6 \ g$$

Total mass $$( C + H )= 2.4 + 0.6 = 3.0 \ g$$

Mass of hydrocarbon = 3.0 g (given)

These data illustrate the law of conservation of mass.

Option (A) is correct.
Question 8
1 / -0

The weights of two elements which combines with one another are in the ratio of their:

A
atomic weight

B
molecular weight

C
equivalent weight

D
none of the above

Solution

According to the law of multiple proportions, when two elements combine to form more than one compound, the weight of one element combined with a fixed weight of the other is in a ratio of small whole numbers.
Hence, the weight of two elements that combine is in the ratio of their atomic weight.
So, the correct option is $$A$$.
Question 9
1 / -0

Weight of oxygen in $$32.2$$ g $$\displaystyle Na_{2}SO_{4}$$.$$\displaystyle 10H_{2}O$$ is:

A
20.8 gm

B
22.4 gm

C
2.24 gm

D
2.08 gm

Solution

Moles of the given compound = $$\displaystyle \frac{32.2}{322}=0.1 \ mol$$

Each molecule contains $$14 \ O \ atoms$$

Moles of oxygen $$= 14\times0.1 = 1.4\ moles$$

Weight of oxygen= $$1.4\times16 = 22.4 \ g$$
Question 10
1 / -0

Modern atomic mass scale is based on the mass of:

A
$$H - 1$$

B
$$C - 12$$

C
$$C - 14$$

D
$$C - 16$$

Solution

Modern atomic weight scale is based on $$C - 12$$.
The standard unit for expressing the mass of atom is amu (atomic mass unit).
It is equal to 1/12 of the mass of an atom of carbon-12 equal to $$1.6605 \times 10^{-19} \: g$$.
amu is also called as avogram.
Avogram is a unit of mass and weight equal to one gram divided by the Avogadro's number.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Atoms and Molecules Test - 34

Result

Atoms and Molecules Test - 34

Score

-

Rank

-

SHARING IS CARING

Question 1

Oxygen

Water

Sugar

Common salt

Solution

Question 2

electron

atom

proton

ions

Solution

Question 3

$$18$$

$$36$$

$$20$$

$$16$$

Solution

Question 4

positive ion

proton

negative ion

none of these

Solution

Question 5

Solutions

Gases

Solids

All of the above

Solution

Question 6

an unstable compound

a stable mixture

an unstable mixture

an extremely stable compound

Solution

Question 7

Conservation of mass

Multiple proportions

Constant proportions

None of the above

Solution

Question 8

atomic weight

molecular weight

equivalent weight

none of the above

Solution

Question 9

20.8 gm

22.4 gm

2.24 gm

2.08 gm

Solution

Question 10

$$H - 1$$

$$C - 12$$

$$C - 14$$

$$C - 16$$

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.