A purified pepsin was subjected to amino acid analysis. The amino acid present in the smallest amount was lysine, C₆H₁₄N₂O₂ and the amount of lysine was found to be 0.431g per 100 g of protein. The minimum molecular mass of protein is:

1. 34 u

2. 3400 u

3. 34,000 u

4. 3,400,000 u

Which of the following represents the total number of valence electrons present in 0.53 g of Na₂CO₃?

1. $3.01\times {10}^{23}$

2. $7.22\times {10}^{22}$

3. $12.046\times {10}^{23}$

4. $6.023\times {10}^{23}$

Which of the following values is closest to the density of CCl₄ vapour (in g/L) at STP? 

1.  8.67

2.  6.87

3.  3.67

4.  4.26

If $3.02\times {10}^{19}$ molecules are removed from 98 mg of H₂SO₄, then the number of moles of H₂SO₄ left are -

1. $0.1\times {10}^{-3}$

2. $9.5\times {10}^{-4}$

3. $1.2\times {10}^{-4}$

4. $0.5\times {10}^{-3}$

A chloride of a metal (M) has 65.5% of chlorine. 100 ml of vapor of the chloride of metal at STP weighs 0.72 g. The molecular formula of this metal chloride is:

1. MCl₃ 

2. MCl₄ 

3. M₂Cl₃ 

4. MCl₅ 

The molality of 0.01 M Na₂CO₃ solution is:
(The density of the solution is 1.1 g/ml)

1. $9\times {10}^{-3}$

2. $1.8\times {10}^{-3}$

3. $4.5\times {10}^{-3}$

4. $1.1\times {10}^{-3}$

What is the weight of 1 × 10²³ molecules of CuSO₄·5H₂O?

1. 42.42 g

2. 41.42 g

3. 44.44 g

4. 48.94 g

If Nₐ is Avogadro’s number, what is the total number of valence electrons present in 4.2 g of N³⁻ ions?

Determine the number of significant figures in the final answer of the expression \(\large{\frac{(29.2-20.2)\times(1.79\times10^5)}{1.37}}\):

When 7.3 g of magnesium bicarbonate (Mg(HCO₃)₂) is decomposed by heating, how much carbon dioxide gas (in mL) is released at STP?

1. 1000 mL

2. 1120 mL

3. 2230 mL

4. 3240 mL