How many grams of NaOH (MW = 40.0) are there in 150.0 mL of a 0.175 M NaOH solution?
0.00219
0.0263
114
14.0
1.05
The correct answer and explanation is :
Solution:
To find the mass of NaOH in the solution, we use the formula:
[
\text{Mass} = \text{Molarity} \times \text{Volume} \times \text{Molar Mass}
]
Step 1: Identify the given values
- Molarity (M) = 0.175 M (moles per liter)
- Volume (V) = 150.0 mL = 0.150 L (convert mL to L)
- Molar Mass of NaOH (MW) = 40.0 g/mol
Step 2: Calculate the number of moles of NaOH
[
\text{Moles of NaOH} = \text{Molarity} \times \text{Volume}
]
[
= 0.175 \times 0.150
]
[
= 0.02625 \text{ moles}
]
Step 3: Convert moles to grams
[
\text{Mass} = \text{Moles} \times \text{Molar Mass}
]
[
= 0.02625 \times 40.0
]
[
= 1.05 \text{ grams}
]
Final Answer:
1.05 g (Correct option: 1.05)
Explanation:
This problem involves a simple molarity to mass conversion. The key steps are:
- Convert mL to L (since molarity is in moles per liter).
- Use Molarity × Volume to find moles of solute.
- Multiply by the molar mass to find the mass in grams.
The most common mistake is forgetting to convert mL to L, which would result in an incorrect answer. Another mistake is misusing the molar mass in calculations.
Thus, 1.05 g of NaOH is present in 150.0 mL of 0.175 M NaOH solution.
Here is an image generated with DALL·E to represent the NaOH solution problem. It features a chemistry beaker with 150.0 mL of clear NaOH solution, a molecular structure of NaOH above it, and a balance scale showing 1.05 grams of NaOH being weighed. The background includes a periodic table and a lab setting.