Calculate the mass of oxygen in grams present in 0.1 mole of `Na_(2)CO_(3).10H_(2)O`

Explanation

To calculate the mass of oxygen in grams present in 0.1 mole of Na₂CO₃·10H₂O, we will follow these steps:

### Step 1: Calculate the molar mass of Na₂CO₃·10H₂O

1. **Identify the components:**
- Sodium (Na): 2 atoms
- Carbon (C): 1 atom
- Oxygen (O) from Na₂CO₃: 3 atoms
- Water (H₂O): 10 molecules

2. **Calculate the molar mass:**
- Molar mass of Na = 23 g/mol
- Molar mass of C = 12 g/mol
- Molar mass of O = 16 g/mol
- Molar mass of H₂O = 18 g/mol

Now calculate:
\[ \text{Molar mass of Na₂CO₃} = (2 \times 23) + (1 \times 12) + (3 \times 16) = 46 + 12 + 48 = 106 \text{ g/mol} \]
\[ \text{Molar mass of 10H₂O} = 10 \times 18 = 180 \text{ g/mol} \]
\[ \text{Total molar mass of Na₂CO₃·10H₂O} = 106 + 180 = 286 \text{ g/mol} \]

### Step 2: Determine the total mass of oxygen in 1 mole of Na₂CO₃·10H₂O

1. **Count the total oxygen atoms:**
- From Na₂CO₃: 3 oxygen atoms
- From 10H₂O: 10 water molecules contribute 10 oxygen atoms

Total oxygen atoms = 3 + 10 = 13 oxygen atoms.

2. **Calculate the mass of oxygen:**
\[ \text{Mass of oxygen in 1 mole} = 13 \times 16 = 208 \text{ g} \]

### Step 3: Calculate the mass of oxygen in 0.1 mole of Na₂CO₃·10H₂O

1. **Use the ratio of moles:**
\[ \text{Mass of oxygen in 0.1 mole} = \left(\frac{208 \text{ g}}{1 \text{ mole}}\right) \times 0.1 \text{ mole} = 20.8 \text{ g} \]

### Final Answer:
The mass of oxygen in grams present in 0.1 mole of Na₂CO₃·10H₂O is **20.8 grams**.

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