Relative Molecular Mass

Q.

What is charge to mass ratio of proton and alpha particles?

Q.

What is the significance of molecular formula?

Q.

The atomic mass of oxygen is 16u.

Considering the above statement, which among the following options can be inferred?

1. The mass is with respect to Carbon -12 atom.

2. The atomic mass of Oxygen is 16 of the mass of carbon 12 atom.

3. The atomic mass of hydrogen is 16 times the mass of Hydrogen.

4. The mass is with respect to Carbon -12 atom and the atomic mass of Oxygen is 16 of the mass of carbon 12 atom.

Q.

Calculate the number of moles in 29.4 g of Sulphuric acid (H₂SO₄).

Q.

Define RMM based on hydrogen as well as carbon-12 scale.

Q.

Why was the mass of an atom initially taken as $\frac{1}{16}th$ of the mass of naturally occurring oxygen as the standard unit?

Q.

The volume of 32 g of oxygen at STP is 224 L.

1. True
2. False

Q.

How many liters of oxygen at STP are required for the combustion of 4g of methane gas? Also, calculate the volume of CO₂ gas produced at STP.

Q.

A gas cylinder of capacity of 20 dm³ is filled with gas X the mass of which is 10 g. When the same cylinder is filled with hydrogen gas at the same temperature and pressure the mass of the hydrogen is 2 g, hence the relative molecular mass of the gas is:

1. 10

2. 5

3. 15

4. 20

Q.

The relative atomic mass of an element has no unit.

1. True
2. False

Q.

The empirical formula of a compound is C₂H₅, and its molecular weight is 58, then its molecular formula is __________.

Q. The vapour density of a gas is twice its relative molecular mass.

1. True
2. False

Q.

What is a molecular formula? Explain its significance using potassium nitrate as an example.

Q.

Assertion- Atomic mass of calcium is 40 u.

Reason- An atom of calcium is 40 times heavier than an atom of carbon with mass 12 u.

1. both assertion and reason are correct and the reason is the correct explanation for assertion.

2. both assertion and reason are correct but reason is not the correct explanation for assertion

3. the assertion is correct but the reason is incorrect

4. the assertion is incorrect but the reason is correct.

Q.

Calculate the volume occupied by 0.01 moles of helium gas at STP.

Q.

What was the need for using relative atomic mass or relative molecular mass?

1. As the mass of atoms or molecules were small
2. To round off every atomic mass as a multiple of 2
3. None of the above
4. To create new terminologies

Q. If the vapour density of the gas is 49.5, find out its molecular weight.

1. 51.5
2. 24.75
3. 49.5
4. 99

Q.

What is a molecular formula?

Q.

Define atomic mass.

Q. Are atomic mass and relative atomic mass exactly the same thing?

Q.

The molecular mass of $H_{2}S{O}_4$ is :

1. 32

2. 64

3. 50

4. 98

Q. The relative molecular masses of hydrogen, nitrogen, oxygen and chlorine are double their relative atomic masses.

1. True
2. False

Q.

The mass of 5.6 ${\mathrm{dm}}^3$ of a certain gas at STP is 12.0 g. Calculate the relative molecular mas of the gas.

Q. A compound of relative molecular mass $34$ and empirical formula $HO$ has the molecular formula $H_2{O}_2$.

1. True
2. False

Q. What is the molar mass of a sulphur molecule.

Q. Calculate the molecular mass of $HN{O}_3$.

Q.

Explain the relation between vapour density and molecular mass.

Q. The relative atomic mass of $Ne$ is $20.$ Its relative molecular mass is:

1. $10$
2. $30$
3. $20$
4. $40$

Q. A volume of gaseous hydrocarbon was exploded with an excess of oxygen. The observed contraction was $2.5V$, and on treatment, with potash, there was a further contraction of $2V$. What is the molecular formula of the hydrocarbon?

1. $C_2{H}_6$
2. $C_3{H}_6$
3. $C_6{H}_{10}$
4. $C_2{H}_4$

Q. Two flasks A and B of equal volumes are kept under similar conditions of temperature and pressure. If flask A holds 16.2 g of gas X while flask B holds 1.012 g of hydrogen, calculate the relative molecular mass of gas X:

1. 20 g
2. 32 g
3. 44 g
4. 28 g