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2 years ago

A buffer is made that is .10M propanoic acid (pKa = 4.9) and .05M sodium propanoate. Calculate the pH.

1 answer:

7 0

PKa= 4.9 therefore ka= 10^-4.9= 1.259x10^-5

$ka= \frac{[H^+][CH3CH2COO^-]}{[CH3CH2COOH]}$

$[CH3CH2COO^-]
$ = 0.05
$[CH3CH2COOH]$ = 0.10

Therefore 1.259x10^-5 = $\frac{[H^+][0.05]}{[0.1]}$
Rearrange the equation to make the concentration of hydrogen the subject.
Therefore $[H^+] = \frac{(1.259*10^-5)(0.1)}{0.05}$

Therefore $[H^+]= 2.513*10^-5$

pH= -log [ $H^+$ ] = -log(2.513*10^-5)= 4.59.

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Lina20 [59]

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3 0

1 year ago

If 3.53 g of CuNO, is dissolved in water to make a 0.330 M solution, what is the volume of the solution in milliliters?

solmaris [256]

Answer:

84.8 mL

Explanation:

From the question given above, the following data were obtained:

Mass of CuNO₃ = 3.53 g

Molarity of CuNO₃ = 0.330 M

Volume of solution =?

Next, we shall determine the number of mole in 3.53 g of CuNO₃. This can be obtained as follow:

Mass of CuNO₃ = 3.53 g

Molar mass of CuNO₃ = 63.5 + 14 + (16×3)

= 63.5 + 14 + 48

= 125.5 g/mol

Mole of CuNO₃ =?

Mole = mass / Molar mass

Mole of CuNO₃ = 3.53 / 125.5

Mole of CuNO₃ = 0.028 moles

Next, we shall determine the volume of the solution. This can be obtained as follow:

Molarity of CuNO₃ = 0.330 M

Mole of CuNO₃ = 0.028 moles

Volume of solution =?

Molarity = mole /Volume

0.330 = 0.028 / Volume

Cross multiply

0.330 × Volume = 0.028

Divide both side by 0.330

Volume = 0.028 / 0.330

Volume = 0.0848 L

Finally, we shall convert 0.0848 L to millilitres (mL). This can be obtained as follow:

1 L = 1000 mL

Therefore,

0.0848 L = 0.0848 L × 1000 mL / 1 L

0.0848 L = 84.8 mL

Therefore, the volume of the solution is 84.8 mL.

8 0

2 years ago

What substance is reduced in the reaction 2Fe 2+ + CI2 = 2Fe 3+ + 2CI- ?

atroni [7]

Answer:

$Cl_{2}$ is reduced in the reaction

Explanation:

The given reaction is

$2Fe^{2+}+Cl_{2} \to 2Fe^{3+}+2Cl^{-}$

The oxidation number of $Fe$ is changed from $+2\, \to \, +3$

$Fe^{2+} \to Fe^{3+}+e^{-}$

And The oxidation number of $Cl$ is changed from $0\, \to \, -1$

$Cl_{2}^{0} + 2e^{-} \to 2Cl^{-}$

Hence, $Fe^{2+}$ is oxidized and $Cl_{2}$ is reduced

5 0

3 years ago

A molecule of acetone and a molecule of propyl aldehyde are both made from 3 carbon atoms, 6 hydrogen atoms, and 1 oxygen atom.

TEA [102]

Explanation:

The structures of both acetone and propanal are shown below:

In the formula of propanal there is -CHO functional group at the end.

In acetone -CO- group is present in the middle that is on the second carbon.

The molecular formula is C3H6O.

Both have same molecular formula but different structural formulas.

7 0

2 years ago

A 52.9g sample of brass, which has a specific heat capacity of 0.375Â·JÂ·g^âˆ’1Â°C^âˆ’1, is put into a calorimeter (see sketch a

vaieri [72.5K]

Answer: 90.04°C

Explanation: <u>Calorimeter</u> is a device measures the amount of heat of a chemical or physical process. An ideal calorimeter is one that is well-insulated, i.e., prevent the transfer of heat between the calorimeter and its surroundings. So, the net heat change inside the calorimeter is zero:

$q_{1}+q_{2}=0$