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4 years ago

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What is the ph of a solution which is 0.025 m in weak base and 0.037 m in the conjugate weak acid (ka = 7.1 × 10–6)?

1 answer:

Elden [556K]4 years ago

4 0

Hello!

This question can be solved using the Henderson-Hasselbach equation, but first we need to know the value of pKa

pKa= -log(Ka)= -log(7,1*10⁻⁶)=5,15

Now, we apply the equation:

$pH=pKa+log \frac{[A^{-}] }{[HA]} =5,15+log( \frac{0,025M}{0,037M} )=4,98$

So, the pH of this solution would be 4,98

Have a nice day!

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This is an incomplete question, here is a complete question.

Ethanol has a heat of vaporization of 38.56 kJ/mol and a normal boiling point of 78.4 °C. What is the vapor pressure of ethanol at 14 °C?

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$\ln (\frac{P_2}{P_1})=\frac{\Delta H_{vap}}{R}\times (\frac{1}{T_1}-\frac{1}{T_2})$

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Now put all the given values in the above formula, we get:

$\ln (\frac{1atm}{P_1})=\frac{38560J/mole}{8.314J/K.mole}\times (\frac{1}{287K}-\frac{1}{351.4K})$

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