Platinum has a molar mass of 195 g/mol. If you have a ring that contains 2.3 g of platinum, how many moles does it contain?

Options

A. 0.012 mol
B. 85 mol
C. 450 mol
D. `72 xx 10^(21) mol`

Answer

To find the number of moles of platinum in the ring, we can use the formula:

\[ \text{Number of moles} = \frac{\text{Mass of substance (g)}}{\text{Molar mass (g/mol)}} \]

### Step-by-step Solution:

1. **Identify the given values**:
- Mass of platinum (m) = 2.3 g
- Molar mass of platinum (M) = 195 g/mol

2. **Use the formula for calculating moles**:
\[ \text{Number of moles} = \frac{m}{M} \]

3. **Substitute the values into the formula**:
\[ \text{Number of moles} = \frac{2.3 \text{ g}}{195 \text{ g/mol}} \]

4. **Perform the division**:
\[ \text{Number of moles} = \frac{2.3}{195} \approx 0.0118 \text{ moles} \]

5. **Round the answer** (if necessary):
- The answer can be rounded to approximately 0.012 moles.

### Final Answer:
The ring contains approximately **0.012 moles** of platinum.

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