Calculate the mass of KHP needed to react completely with 15 mL of a 0.10 M NaOH solution. Consider the reaction equation to be as shown below, molar mass of KHP is 204.3g/mol
The correct answer and explanation is :
To calculate the mass of Potassium Hydrogen Phthalate (KHP) needed to react completely with 15 mL of a 0.10 M NaOH solution, let’s break down the problem step by step.
Step 1: Write the balanced chemical equation
The balanced equation for the reaction between NaOH and KHP is:
[
\text{KHP (aq)} + \text{NaOH (aq)} \rightarrow \text{NaKP (aq)} + \text{H}_2\text{O (l)}
]
From this equation, we see that KHP reacts with NaOH in a 1:1 molar ratio. This means that for every mole of NaOH, 1 mole of KHP is needed.
Step 2: Calculate the moles of NaOH
We are given:
- Volume of NaOH solution = 15 mL = 0.015 L
- Molarity of NaOH solution = 0.10 M
Using the formula for molarity:
[
\text{Moles of NaOH} = M \times V
]
Where:
- ( M ) is the molarity (0.10 M)
- ( V ) is the volume (0.015 L)
[
\text{Moles of NaOH} = 0.10 \, \text{mol/L} \times 0.015 \, \text{L} = 0.0015 \, \text{mol NaOH}
]
Since the molar ratio between NaOH and KHP is 1:1, the moles of KHP required will be the same as the moles of NaOH:
[
\text{Moles of KHP} = 0.0015 \, \text{mol}
]
Step 3: Calculate the mass of KHP
We are given the molar mass of KHP as 204.3 g/mol. To find the mass of KHP needed, we use the formula:
[
\text{Mass of KHP} = \text{moles of KHP} \times \text{molar mass of KHP}
]
[
\text{Mass of KHP} = 0.0015 \, \text{mol} \times 204.3 \, \text{g/mol}
]
[
\text{Mass of KHP} = 0.30645 \, \text{g}
]
Final Answer:
The mass of KHP needed to react completely with 15 mL of a 0.10 M NaOH solution is approximately 0.306 g.
Explanation:
In this calculation, the key concept is understanding the molar ratio in the balanced chemical equation. Since the reaction between NaOH and KHP occurs in a 1:1 ratio, the moles of NaOH directly correspond to the moles of KHP needed. Using the molarity and volume of the NaOH solution, we calculated the moles of NaOH and used the same value to find the moles of KHP. Finally, by multiplying the moles of KHP by its molar mass, we determined the required mass of KHP to fully react with the NaOH solution.