Question

Find the number of millimoles for 0.160 g sodium hydroxide.

• A. 0.08
• B. 0.20
• C. 4.00
• D. 40.00

Hint:

$\text{Millimoles} = \frac{\text{Mass in grams}}{\text{Molar mass}} \times 1000$.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
We need to convert a given mass of NaOH into millimoles.
Step 2: Key Formula or Approach:
1. \( \text{Moles} = \frac{\text{Mass}}{\text{Molar Mass}} \)
2. \( \text{Millimoles} = \text{Moles} \times 1000 \)
Step 3: Detailed Explanation:
Molar mass of Sodium Hydroxide (\( NaOH \)):
- Na = 23 g/mol
- O = 16 g/mol
- H = 1 g/mol
Total = \( 23 + 16 + 1 = 40 \text{ g/mol} \).
Calculate moles:
\[ \text{Moles} = \frac{0.160 \text{ g}}{40 \text{ g/mol}} = 0.004 \text{ mol} \]
Calculate millimoles:
\[ \text{Millimoles} = 0.004 \times 1000 = 4.00 \text{ mmol} \]
Step 4: Final Answer:
The number of millimoles is 4.00.