Some Basic Concepts of Chemistry Test

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Some Basic Concepts of Chemistry Test - 63

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Weekly Quiz Competition

Question 1
1 / -0

What is the % of acetic acid present in vinegar?

A
6-10%

B
70-80%

C
7-8%

D
90-100%

Solution

$$Vinegar$$ is 6-10 % $$\text{aqueous solution of acetic acid}$$
Question 2
1 / -0

10 grams of a solute is dissolved in 90 grams of a solvent. Its mass percent in solution is

A
0.01

B
11.1

C
10

D
9

Solution

$$\%$$ by wt.$$ = \dfrac {wt. \,of \,the \,solute (g)}{wt. \,of \,the \,solution(g)} \times 100$$

$$\%$$ by wt $$ = \dfrac {10}{90 + 10} \times 100 = 10\%$$
Question 3
1 / -0

1 amu is equal to

A
$$\dfrac{1}{12}$$ of C-12

B
$$\dfrac{1}{14}$$ of O-16

C
$$1\,g$$ of hydrogen

D
$$1.66 \times 10^{-23} kg$$

Solution

One atomic mass unit or amu is a mass unit equal to exactly one-twelfth (1/12th) the mass of one atom of carbon-12.
Question 4
1 / -0

Which of the following reactions is not according to the law of conservation of mass?

A
$$2Mg(s)+O_2(g)\to 2MgO(s)$$

B
$$C_3H_3(g)+O_2(g)\to CO_2(g)+H_2O(g)$$

C
$$P_4(s)+5O_2(g)\to P_4O_{10}(s)$$

D
$$CH_4(g)+2O_2(g)\to CO_2(g)+2H_2O(g)$$

Solution

Number of atoms in the reactant side is not equal to the number of atoms in the product side for the reaction given in option B.
Question 5
1 / -0

The accepted unit of atomic and molecular mass is:

A
kilogram

B
gram

C
pound

D
atomic mass unit

Solution

Accepted as unit of atomic and molecular mass is atomic mass unit (u).
Question 6
1 / -0

What is atomic mass of $$He$$ in amu $$(u)$$ units?

A
$$8$$

B
$$9$$

C
$$2$$

D
$$4$$

Solution

The atomic mass of an element is the average mass of an element measured in an atomic mass unit (amu). The atomic mass of $$He$$ is $$4\ u$$.
Option $$D$$ is correct.
Question 7
1 / -0

Which of the given laws of chemical combination is satisfied by the figure?

A
Law of multiple proportion

B
Gay Lussac's law

C
Avogadro law

D
Law of definite proportion

Solution
Question 8
1 / -0

When $$2.5\,g$$ of a sample of Mohr's salt reacts completely with $$50\,mL $$ of $$ \dfrac{N}{10} KMnO_4 $$ solution. The % purity of the sample of Mohr's salt is:

A
$$78.4 $$

B
$$70$$

C
$$37$$

D
$$40$$

Solution

meq. $$FeSO_4 (NH_4)_2SO_4. 6H_2O $$ = meq. of $$KMnO_4 $$
$$ (n = 1) $$
$$ \dfrac{W}{392} \times 1 \times 1000 = 0.1 \times 50 $$ ;
$$ W = 1.96\,g $$
Hence, $$\%$$ purity of Mohr's salt
$$ = \dfrac{1.96}{2.5} \times 100 = 78.4 \%$$
Question 9
1 / -0

What percentage ox oxygen is present in the compound $$CaCO_3. 3Ca_3(PO_4)_2 $$?

A
$$23.3\% $$

B
$$45.36\%$$

C
$$41.94\%$$

D
$$17.08\%$$

Solution

$$\%$$ of $$O = \dfrac{16 \times 27}{(100 + 3 \times 310)} \times 100 = 41.94\%$$
Question 10
1 / -0

$$2.0\,g$$ sample contain mixture of $$SiO_{2}$$ and $$Fe_{2}O_{3}$$ , on very strong heating leave a residue weighing $$1.96\,g$$ . The reaction responsible for loss of weight is
$$ Fe_{2}O_{3} (s) \rightarrow Fe_{3}O_{4} (s) + O_{2} (g) $$ (unbalanced equation)
what is the percentage of mass of $$SiO_{2}$$ in original sample?

A
$$10\%$$

B
$$20\%$$

C
$$40\%$$

D
$$60\%$$

Solution

$$3Fe_2O_3(s) \longrightarrow 2Fe_3O_4 + \dfrac{1}{2} O_2 $$

$$480\,g \, Fe_2O_3 $$ provide $$16\,g \, O_2 $$.
For loss of $$0.04\,g O_2 \rightarrow 0.04 \times \dfrac{480}{16} = 1.2 \,g \, Fe_2O_3 $$

$$\%$$ of mass of $$SiO_2 = \dfrac{0.8}{2.0} \times 100 = 40\%$$

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Re-Attempt Weekly Quiz Competition

Some Basic Concepts of Chemistry Test - 63

Result

Some Basic Concepts of Chemistry Test - 63

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SHARING IS CARING

Question 1

6-10%

70-80%

7-8%

90-100%

Solution

Question 2

0.01

11.1

10

9

Solution

Question 3

$$\dfrac{1}{12}$$ of C-12

$$\dfrac{1}{14}$$ of O-16

$$1\,g$$ of hydrogen

$$1.66 \times 10^{-23} kg$$

Solution

Question 4

$$2Mg(s)+O_2(g)\to 2MgO(s)$$

$$C_3H_3(g)+O_2(g)\to CO_2(g)+H_2O(g)$$

$$P_4(s)+5O_2(g)\to P_4O_{10}(s)$$

$$CH_4(g)+2O_2(g)\to CO_2(g)+2H_2O(g)$$

Solution

Question 5

kilogram

gram

pound

atomic mass unit

Solution

Question 6

$$8$$

$$9$$

$$2$$

$$4$$

Solution

Question 7

Law of multiple proportion

Gay Lussac's law

Avogadro law

Law of definite proportion

Solution

Question 8

$$78.4 $$

$$70$$

$$37$$

$$40$$

Solution

Question 9

$$23.3\% $$

$$45.36\%$$

$$41.94\%$$

$$17.08\%$$

Solution

Question 10

$$10\%$$

$$20\%$$

$$40\%$$

$$60\%$$

Solution

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