PASSAGE-I :A mole of an atom is a collection of atoms whose total mass is the number of grams equal to the atomic mass. Since equal number of moles of different elements contain an equal number of atoms it becomes convenient to express the amounts of the elements in terms of moles. A mole represents a definite number of particles viz, atoms, molecules, ions or electrons. This definite number is called Avogadro number or Avogadro constant which is equal to `6.022 xx 10^(23)` Hence a mole represents `6.022 xx 10^(23)` particles of the substance. One mole of substance represents one gram-formula of the substance. One mole of a gas at standard temperature and pressure occupies 22.4 litres.
What is the mass in grams of 2.42 mol of zinc? (Atomic mass of Zn = 65.41)

Options

A. 200 g
B. 25 g
C. 85 g
D. 158 g

Explanation

To find the mass in grams of 2.42 moles of zinc (Zn), we can follow these steps:

### Step 1: Understand the relationship between moles and mass
A mole of any substance contains a specific number of particles (Avogadro's number, which is approximately \(6.022 \times 10^{23}\)). The mass of one mole of an element in grams is numerically equal to its atomic mass in atomic mass units (amu).

### Step 2: Identify the atomic mass of zinc
The atomic mass of zinc (Zn) is given as 65.41 g/mol. This means that one mole of zinc weighs 65.41 grams.

### Step 3: Calculate the mass of 2.42 moles of zinc
To find the mass of 2.42 moles of zinc, we can use the formula:
\[ \text{Mass} = \text{Number of moles} \times \text{Molar mass} \]
Substituting the values:
\[ \text{Mass} = 2.42 \, \text{mol} \times 65.41 \, \text{g/mol} \]

### Step 4: Perform the multiplication
Calculating the above expression:
\[ \text{Mass} = 2.42 \times 65.41 = 158.8 \, \text{grams} \]

### Step 5: Round the answer
The final mass of 2.42 moles of zinc is approximately 158.8 grams. Depending on the required precision, we can round it to 159 grams.

### Final Answer
The mass in grams of 2.42 moles of zinc is approximately **158.8 grams**.

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