Which of the following has the smallest mass?

(a)

6.023 × 10²³ atoms of He

(b)

1 atom of He

(c)

2 g of He

(d)

1 mole atoms of He

Which of the following represents 1 amu?

(a)

Mass of a C – 12 atom

(b)

Mass of a hydrogen atom

(c)

1/12^th of the mass of a C – 12 atom

(d)

Mass of O – 16 atom

In the nucleus of ₂₀Ca⁴⁰, there are 

(a)

20 protons and 40 neutrons

(b)

20 protons and 20 neutrons

(c)

20 protons and 40 electrons

(d)

40 protons and 20 electrons

Pick out the isotopes among the following pairs

(a)

₆C¹³, ₇N¹⁴

(b)

₁₈Ar⁴, ₂₀Ca⁴

(c)

₆C¹², C₆¹⁴

(d)

₅B¹², ₆C¹³

Mass number is the

(a)

Number of protons

(b)

Sum of protons and electrons

(c)

Number of neutrons

(d)

Sum of protons and neutrons

Mass of an electron is

(a)

9.1083 x 10^-31kg

(b)

9.1083 x 10^-24kg

(c)

1.67262 x 10^-27kg

(d)

1.67 x 10^-24gm

The relative atomic masses of many elements are not whole number because

(a)

they are not determined accurately

(b)

they exist as isotopes

(c)

due to impurities

(d)

atoms ionize

Total number of atoms in 4g of oxygen molecule is

(a)

6.023 x 10²³

(b)

7.52 x 10²²

(c)

1.5055 x 10²³

(d)

0.0752 x 10²³

What mass of hydrogen and oxygen will be produced on complete electrolysis of 18 g of water

(a)

2 g hydrogen and 32 g oxygen

(b)

2 g hydrogen and 16 g oxygen

(c)

4 g hydrogen and 32 g oxygen

(d)

4 g hydrogen and 14 g oxygen

Which of the following has largest number of particles?

(a)

8g of CH₄

(b)

4.4g of CO₂

(c)

34.2g of C₁₂H₂₂P₁₁

(d)

2g of H₂

The formula of a chloride of a metal M is MCl₃ the formula of the phosphate of metal M will be:

(a)

MPO₄

(b)

M₂PO₄

(c)

M₃PO₄

(d)

2 (PO₄)₃

The mass of one C atom is

(a)

6.023 x 10²³g

(b)

1.99 x 10^-23g

(c)

2.00 g

(d)

12 g

The total number of atoms represented by the compound CuSO₄. 5H₂O is

(a)

27

(b)

21

(c)

5

(d)

8

How many molecules are present in one gram of hydrogen?

(a)

6.023 x 10²³

(b)

3.0115 x 10²³

(c)

2.5 x 10²³

(d)

1.5 x 10²³

Isotopes have

(a)

Same physical properties and different chemical properties

(b)

Same chemical properties and different physical properties

(c)

Same physical and chemical properties

(d)

Different physical and chemical properties