Molar Mass

Q. Choose the option depicting the correct order of molecular mass of
the given compounds.
NaO, NaOH, NaCl

1. NaO < NaCl < NaOH
2. NaO < NaOH < NaCl
3. NaOH < NaO < NaCl
4. NaOH < NaCl < NaO

Q. Mass of a given substance = Number of moles $\times$ gram molecular mass of the substance.

1. True
2. False

Q.

34 g of Ammonia is decomposed to _________ g of Nitrogen and _____ g of Hydrogen, _____ is the ratio of Hydrogen to Nitrogen by mass. The options in blanks are respectively

1. 28, 3 and 28:3

2. 14, 6 and 14:6

3. 28, 6 and 14:3

4. 14, 3 and 14:3

Q.

What is the number of moles of hydrogen atom in 72 g of water?

1. 3

2. 1

3. 2

4. 4

Q.

34 g of $H_{2}O$ decomposes to _______ g of hydrogen and ____ g of oxygen.

1. 30 gm of oxygen and 4 gm of hydrogen

2. 16 gm of oxygen and 18 gm of hydrogen

3. 3.78 gm H₂ and 30.22 gm O_2.

4. 32 gm of oxygen and 2 grams of hydrogen

Q. The mass of 1 mole of an element expressed in grams is called its gram atomic mass.

1. True
2. False

Q. What is the mass of one atom of neon if its gram atomic mass is 20 grams?

1. $3.32\times {10}^{-23}$ grams
2. $5.32\times {10}^{-23}$ grams
3. $4.32\times {10}^{-23}$ grams
4. $2.65\times {10}^{-23}$ grams

Q.

Calculate the molecular mass of Na₂CO_3.

1. 51 u

2. 74 u

3. 130 u

4. 106 u

Q. What is the number of oxygen atoms present in 126 g of ${HNO}_3$?

1. $16.132\times {10}^{23}$
2. $36.132\times {10}^{23}$
3. $9.033\times {10}^{23}$
4. $120.44\times {10}^{23}$

Q.

In an experiment the following reactions takes place:
$X+Y\to Z2g4gug$

$Z+A\to Bug7gcg$

What is the value of u and c respectively?

1. 9.8 gm

2. 1.2 gm

3. 10.8 gm

4. 11.2 gm