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3 years ago

How does water's dissolving power support life on Earth?

1 answer:

6 0

The dissolving power of water is very important for life on Earth. Wherever water goes, it carries dissolved chemicals, minerals, and nutrients that are used to support living things. Because of their polarity, water molecules are strongly attracted to one another, which gives water a high surface tension

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Calculate the EMF between copper and silver Ag+e-E=0.89v Cu=E=0.34v

bogdanovich [222]

Answer:

Depending on the $E^\circ$ value of $\rm Ag^{+} + e^{-} \to Ag\; (s)$ , the cell potential would be:

$0.55\; \rm V$ , using data from this particular question; or
approximately $0.46\; \rm V$ , using data from the CRC handbooks.

Explanation:

In this galvanic cell, the following two reactions are going on:

The conversion between $\rm Ag\; (s)$ and $\rm Ag^{+}$ ions, $\rm Ag^{+} + e^{-} \rightleftharpoons Ag\; (s)$ , and
The conversion between $\rm Cu\; (s)$ and $\rm Cu^{2+}$ ions, $\rm Cu^{2+}\; (aq) + 2\, e^{-} \rightleftharpoons \rm Cu\; (s)$ .

Note that the standard reduction potential of $\rm Ag^{+}$ ions to $\rm Ag\; (s)$ is higher than that of $\rm Cu^{2+}$ ions to $\rm Cu\; (s)$ . Alternatively, consider the fact that in the metal activity series, copper is more reactive than silver. Either way, the reaction is this cell will be spontaneous (and will generate a positive EMF) only if $\rm Ag^{+}$ ions are reduced while $\rm Cu\; (s)$ is oxidized.

Therefore:

The reduction reaction at the cathode will be: $\rm Ag^{+} + e^{-} \to Ag\; (s)$ . The standard cell potential of this reaction (according to this question) is $E(\text{cathode}) = 0.89\; \rm V$ . According to the 2012 CRC handbook, that value will be approximately $0.79\; \rm V$ .

The oxidation at the anode will be: $\rm Cu\; (s) \to \rm Cu^{2+} + 2\, e^{-}$ . According to this question, this reaction in the opposite direction ( $\rm Cu^{2+}\; (aq) + 2\, e^{-} \rightleftharpoons \rm Cu\; (s)$ ) has an electrode potential of $0.34\; \rm V$ . When that reaction is inverted, the electrode potential will also be inverted. Therefore, $E(\text{anode}) = -0.34\; \rm V$ .

The cell potential is the sum of the electrode potentials at the cathode and at the anode:

$\begin{aligned}E(\text{cell}) &= E(\text{cathode}) + E(\text{anode}) \\ &= 0.89 \; \rm V + (-0.34\; \rm V) = 0.55\; \rm V\end{aligned}$ .

Using data from the 1985 and 2012 CRC Handbook:

$\begin{aligned}E(\text{cell}) &= E(\text{cathode}) + E(\text{anode}) \\ &\approx 0.7996 \; \rm V + (-0.337\; \rm V) \approx 0.46\; \rm V\end{aligned}$ .

5 0

3 years ago

2p is the correct representation for the sub-shell with n = 2 and l = 1.

boyakko [2]

Explanation:

Principle Quantum Numbers : It describes the size of the orbital and the energy level. It is represented by n. Where, n = 1,2,3,4....

Azimuthal Quantum Number : It describes the shape of the orbital. It is represented as 'l'. The value of l ranges from 0 to (n-1). For l = 0,1,2,3... the orbitals are s, p, d, f...

s = 1 orbital

p = 3 orbitals

d = 5 orbitals

f = 7 orbitals

For n = 4

l = 0 to (n-1) = 0 to 3 = (4s , 4p , 4d , 4f)

Number of subshells = 4

Number of orbitals = 1 + 3 + 5 + 7 = 16

The maximum number of electrons the n = 4 shell can contain:

Each orbital can holds upto two electrons, then 16 orbitals will have :

$16\times 2=32$

32 is the maximum number of electrons the n = 4 shell can contain

6 0

3 years ago

Read 2 more answers

Which statement regarding the second law of thermodynamics is true?

GREYUIT [131]

The Second Law of Thermodynamics says that processes that involve the transfer or conversion of heat energy are irreversible. ... The First Law of Thermodynamics states that energy cannot be created or destroyed; the total quantity of energy in the universe stays the same.

4 0

3 years ago

How can you find a tutor??

yanalaym [24]

Depending on what you are doing, virtual, or in school, you can contact your school and you ask them, or you can have your teacher, based on the subject, tutor you.

7 0

3 years ago

Read 2 more answers

Help me please thanks

Evgesh-ka [11]

Then answer would be D. Answer D is correct because you would need to use a better solvent to see the ink separate on the chromatography paper. Hope that helps. :)

6 0

3 years ago