Tetragonal crystal system has the following unit cell dimensions `:`

Options

A. (a) cubic
B. (b) tetragonal
C. (c) monoclinic
D. (d) rhombohedral

Answer

To solve the problem regarding the evaporation of water and the calculation of the heat of vaporization (ΔH) using the given parameters, we can follow these steps:

### Step 1: Calculate the Heat Energy (H)
We know that power (P) is equal to heat (H) divided by time (t). Therefore, we can rearrange this formula to find heat:

\[ H = P \times t \]

Given:
- Power (P) = 806 watts
- Time (t) = 100 seconds

Substituting the values:

\[ H = 806 \, \text{W} \times 100 \, \text{s} = 80600 \, \text{J} \]

### Step 2: Calculate the Mass of Water
We can calculate the mass of water using the density and volume. The formula for mass (m) is:

\[ m = \text{Density} \times \text{Volume} \]

Given:
- Density of water = 1 g/cm³
- Volume = 36 ml = 36 cm³ (since 1 ml = 1 cm³)

Substituting the values:

\[ m = 1 \, \text{g/cm}^3 \times 36 \, \text{cm}^3 = 36 \, \text{g} \]

### Step 3: Calculate the Heat of Vaporization (ΔH)
The heat of vaporization can be calculated using the formula:

\[ \Delta H = \frac{H}{m} \times \text{Molar Mass} \]

Where:
- H = 80600 J (calculated in Step 1)
- m = 36 g (calculated in Step 2)
- Molar mass of water = 18 g/mol

Substituting the values:

\[ \Delta H = \frac{80600 \, \text{J}}{36 \, \text{g}} \times 18 \, \text{g/mol} \]

Calculating:

\[ \Delta H = \frac{80600}{36} \times 18 \]

\[ \Delta H = 2233.33 \times 18 \]

\[ \Delta H = 40300 \, \text{J/mol} \]

### Step 4: Convert ΔH to kJ/mol
To convert joules to kilojoules, we divide by 1000:

\[ \Delta H = \frac{40300 \, \text{J/mol}}{1000} = 40.3 \, \text{kJ/mol} \]

### Final Answer
The heat of vaporization (ΔH) of water is **40.3 kJ/mol**.

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