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4 years ago

What is the ph of a solution that has 0.075 m ch3cooh and 0.050m nach3coo present? ka for acetic acid = 1.80 x 10-5?

1 answer:

7 0

Hello!

For solving this problem we first have to determine the pKa of CH₃COOH.

$pKa=-log(Ka)=-log( 1,80*10^{-5} )=4,74$

Now, we use the Henderson-Hasselbach's equation to determine the pH of the buffer solution:

$pH=pKa+log (\frac{NaCH_3COO}{CH_3COOH} )=4,74+log( \frac{0,050M}{0,075M} )=4,56$

So, the pH of this solution is 4,56

Have a nice day!

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The standard reduction potentials for the Ag+|Ag(s) and Zn2+| Zn(s) half-cell reactions are +0.799 V and -0.762 V, respectively.

mihalych1998 [28]

Answer: The potential of the given cell is 1.551 V

Explanation:

The given chemical cell follows:

$Zn(s)|Zn^{2+}(0.125M)||Ag^{+}(0.240M)|Ag(s)$

Oxidation half reaction: $Zn(s)\rightarrow Zn^{2+}(0.125M)+2e^-;E^o_{Zn^{2+}/Zn}=-0.762V$

Reduction half reaction: $Ag^{+}(0.240M)+e^-\rightarrow Ag(s);E^o_{Ag^{+}/Ag}=0.799V$ ( × 2)

Net cell reaction: $Zn(s)+2Ag^{+}(0.240M)\rightarrow Zn^{2+}(0.125M)+2Ag(s)$

Oxidation reaction occurs at anode and reduction reaction occurs at cathode.

To calculate the $E^o_{cell}$ of the reaction, we use the equation:

$E^o_{cell}=E^o_{cathode}-E^o_{anode}$

Putting values in above equation, we get:

$E^o_{cell}=0.799-(-0.762)=1.561V$

To calculate the EMF of the cell, we use the Nernst equation, which is:

$E_{cell}=E^o_{cell}-\frac{0.059}{n}\log \frac{[Zn^{2+}]}{[Ag^{+}]^2}$

where,

$E_{cell}$ = electrode potential of the cell = ? V

$E^o_{cell}$ = standard electrode potential of the cell = +1.561 V

n = number of electrons exchanged = 2

$[Zn^{2+}]=0.125M$

$[Ag^{+}]=0.240M$

Putting values in above equation, we get:

$E_{cell}=1.561-\frac{0.059}{2}\times \log(\frac{(0.125)}{(0.240)^2})$

$E_{cell}=1.551V$

Hence, the potential of the given cell is 1.551 V

6 0

4 years ago

What mass of fes is formed if 9.42 g of fe reacts with 68.0 g of s8? 8fe(s) + s8(s) â†’ 8fes(s)?

allochka39001 [22]

From the equation, we see that the molar ratio of Fe : S required is:

8 : 1

The moles of Fe present are: 9.42/56 = 0.168
Moles of S = 68/(32 * 8) = 0.265

The molar ratio is:

1 : 1.6

Therefore, iron is the limiting reactant as it is present in a ratio lower than that required. The ratio of

Fe : FeS is
1 : 1

So 0.168 moles of FeS will form. The mass of FeS will be:

Mass = 0.168 * (56 + 32)
Mass = 14.78 grams

14.78 grams of FeS will be formed.

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4 years ago

An atom has atomic number 5 and mass number 11. How many protons does the atom have? 5 6 10 11

spin [16.1K]

Answer:

6 neutrons. The mass number is the number of protons and neutrons in the nucleus of an atom. The atomic number shows how many protons. Subract the atomic number from the mass number to find the number of neutrons.

Explanation:

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Answer:

The correct answer is C.) metallic bonds

Explanation:

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Answer:

All igneous rocks the basis of the rock cycle are formed by plate tectonics. ... The heat from the mantle that fuels plate tectonics causes both igneous and sedimentary rocks to be turned into metamorphic rocks. The metamorphic rocks can be eroded into sedimentary rocks are remelted back into igneous.

Explanation:

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