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When 0.6g of urea dissolved in 100g of w...

When `0.6g` of urea dissolved in `100g` of water, the water will boil at `(K_(b)` for water `= 0.52kJ. mol^(-1)` and normal boiling point of water `=100^(@)C)`:

A

`373.052 K`

B

`273.52K`

C

`372.48K`

D

`273.052K`

Text Solution

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The correct Answer is:
To solve the problem of determining the boiling point of water when 0.6 g of urea is dissolved in 100 g of water, we will follow these steps: ### Step 1: Calculate the number of moles of urea To find the number of moles of urea, we use the formula: \[ \text{Number of moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} \] The molar mass of urea (NH₂CONH₂) is approximately 60 g/mol. \[ \text{Number of moles of urea} = \frac{0.6 \, \text{g}}{60 \, \text{g/mol}} = 0.01 \, \text{mol} \] ### Step 2: Convert the mass of water to kilograms Since the weight of the solvent (water) needs to be in kilograms for the calculation, we convert 100 g to kg: \[ \text{Weight of water} = 100 \, \text{g} = 0.1 \, \text{kg} \] ### Step 3: Calculate the boiling point elevation (ΔT_b) Using the formula for boiling point elevation: \[ \Delta T_b = K_b \cdot \frac{n}{m} \] Where: - \( K_b = 0.52 \, \text{K kg/mol} \) - \( n = \text{number of moles of solute} = 0.01 \, \text{mol} \) - \( m = \text{mass of solvent in kg} = 0.1 \, \text{kg} \) Substituting the values: \[ \Delta T_b = 0.52 \, \text{K kg/mol} \cdot \frac{0.01 \, \text{mol}}{0.1 \, \text{kg}} = 0.052 \, \text{K} \] ### Step 4: Calculate the new boiling point of the solution The normal boiling point of water (T₀_b) is 100 °C, which is equivalent to 373 K. The boiling point of the solution (T_b) can be calculated as: \[ T_b = T_0_b + \Delta T_b \] Substituting the values: \[ T_b = 373 \, \text{K} + 0.052 \, \text{K} = 373.052 \, \text{K} \] ### Step 5: Convert the boiling point back to Celsius (if needed) Since the question asks for the boiling point in Celsius, we can convert it back: \[ T_b = 373.052 \, \text{K} - 273 = 100.052 \, \text{°C} \] ### Final Answer The boiling point of the solution is approximately **100.052 °C**. ---

To solve the problem of determining the boiling point of water when 0.6 g of urea is dissolved in 100 g of water, we will follow these steps: ### Step 1: Calculate the number of moles of urea To find the number of moles of urea, we use the formula: \[ \text{Number of moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} \] ...
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Knowledge Check

  • Elevation in boiling point was 0.52^(@)C when 6 g of a compound X was dissolved in 100 g of water. Molecular weight of X is ( K_(b) of water is 5.2^(@)C per 100 g of water)

    A
    120
    B
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    D
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  • An aqueous dilute solution containing non- volatile solute boils at 100.052 ""^(@) C what is the molality of solution ? K_(b) = 0.52 kg mol ^(-1) K, Boiling temperature of water =100^(@) C )

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    B
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