20 calories equals to 8.368 joules.
4.184 J is needed to raise 1 gram of water.(Heat capacity of water)
for 2 grams of water 8.368 joules.
So the answer is 16 c.
The required mass of argon in given number of atoms of argon is 155.61 grams.
<h3>What is Avogadro's number?</h3>
Avogadro's number is the number of atoms which are present in 1 mole of any substance and it is equal to 6.022×10²³.
Relation between the mass and moles of any substance will be represented as:
- n = W/M, where
- W = given mass
- M = molar mass
So, moles of argon will be calculated by using given number of atoms as:
Moles = 2.4×10²⁴ atoms / 6.022×10²³ atoms per mole
Moles = 3.9 moles
Now mass will be:
W = (3.9mol)(39.9g/mol) = 155.61 g
Hence required mass of argon is 155.6g.
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Answer:
Reduced species and oxidizing agent: sulfur in the form of sulfate.
Oxidized species and reducing agent: chromium in the form of chromous hydroxide.
Explanation:
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In this case, for the reaction:

We can see that the oxidation states of sulfur and chromium change from +6 to +4 and +3 to +6 respectively; in such a way, since the oxidized species is the same reducing agent because it undergoes an increase in the oxidation state, we infer that chromium is it as it goes from +3 to +6.
Moreover, since the reduced species is the same oxidizing agent because it undergoes a decrease in the oxidation state, we infer that sulfur is it as it goes from +6 to +4.
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Mole of electron required by
mole is 
- Faraday law expressed how the change that is been being produced by a current at an electrode-electrolyte interface is related and proportional to the quantity of electricity that is been used.
- There is one mole of electron required for 1 Faraday of electricity.
- Avogadro constant is

- Mole of electron can be calculated by dividing the number of electron by avogadro's constant.
=
= 
Therefore, it requires
Faraday of electricity for the 
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