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Write three complete and balanced pairs of below mention electrochemical half reactions. For each pair of reactions, identify wh

kirza4 [7]

Answer: a) $Cu\rightarrow Cu^{2+}+2e^-$ : anode

b. $2H^++2e^-\rightarrow H_2$ : cathode

c. $O^{2-}\rightarrow \frac{1}{2}O_2+2e^-$ : anode

Explanation:

Electrochemical cell is a device which converts chemical energy into electrical energy. It consist of two electrodes, anode and cathode.

Oxidation i.e. loss of electrons , which results in an increase in oxidation number occurs over anode.

Reduction i.e. gain of electrons, which results in decrease in oxidation number occurs over cathode.

a. $Cu\rightarrow Cu^{2+}+2e^-$ : oxidation : anode

b. $2H^++2e^-\rightarrow H_2$ : reduction : cathode

c. $O^{2-}\rightarrow \frac{1}{2}O_2+2e^-$ : oxidation : anode

6 0

3 years ago

The chemical equation for the formation of ammonia is unbalanced.

ratelena [41]

Balance Chemical equation is as follow,

 3 H₂ (g) + N₂ (g) → 2 NH₃ (g)

According to balanced equation, 3 Molecules (3 moles) of Hydrogen reacts with 1 Molecule of N₂ to produce 2 moles (2 Molecules) of NH₃.

Result:
2 Molecules of Ammonia are produced by reacting 3 molecules of Hydrogen and 1 molecule of Nitrogen.

7 0

3 years ago

How is electron movement related to the bonding in sodium chloride?

stepladder [879]

Cl is highly electronegative and will actually pull away 1 electron from sodium, forming an ionic bond.

5 0

3 years ago

Read 2 more answers

An experiment to measure the enthalpy change for the reaction of aqueous

Komok [63]

Given that, an experiment to measure the enthalpy change for the reaction of aqueous copper(II) sulfate, CuSO4(aq) and zinc, Zn(s) was carried out in a coffee cup calorimeter; the heat of the reaction in the whole system is calculated to be 2218.34 kJ

Heat of reaction (i.e enthalpy of reaction) is the quantity of heat that is required to be added or removed when a chemical reaction is taken place in order to maintain all of the compounds present at the same temperature.

The formula used to calculate the heat of the reaction can be expressed as follows:

Q = mcΔT

where:

Q = quantity of heat transfer
m = mass
c = specific heat of water = 4.18 kJ/g °C (constant)
ΔT = change in temparature

From the information given:

The initial temperature (T₁) = 25° C
The final temperature (T₂) = 91.5° C

∴

The change in temperature i.e. ΔT = T₂ - T₁

ΔT = 91.5° C - 25° C

ΔT = 66.5° C

The number of moles of CuSO₄ = 1.00 mol/dm³ × 50.0 cm³

$\mathbf{= (1 \times \dfrac{50}{1000})\ moles}$

= 0.05 moles

Since the molar mass of CuSO₄ = 159.609 g/mol

Then;

Using the relation:

$\mathbf{number \ of \ moles = \dfrac{mass}{molar \ mass}}}$

By crossing multiplying;

mass of CuSO₄ = number of moles of CuSO₄ × molar mass of CuSO₄

mass of CuSO₄ = 0.05 moles × 159.609 g/moles

mass of CuSO₄ = 7.9805 grams

∴

Using the formula from above:

Q = mcΔT

Q = 7.9805 g × 4.18 kJ/g °C × 66.5° C

Q = 2218.34 kJ

Therefore, we can conclude that the heat of the reaction is 2218.34 kJ

Learn more about the chemical reaction here:

brainly.com/question/20250226?referrer=searchResults

8 0

2 years ago

Which of the following equations does not demonstrate the law of conservation of mass?

enot [183]

The third option does not obey the law of conservation of mass.

Option 3.

Explanation:

The law of conservation of mass states that the sum of the masses of reactants should be equal to the sum of the masses of the products.

For example, if we consider the first option to verify if it obeys law of conservation of mass or not, 2 Na + Cl₂ → 2 NaCl

So one way to verify it is to find the mass of Na, then multiply it with 2, and then add this with 2 times of mass of chlorine. So this sum should be equal to the 2 times mass of NaCl. But it is somewhat lengthy.

Another way to easily determine this is to check if the elements are present equally in both sides. Such as, in reactant side and product side 2 atoms of Na is present . Similarly, the Cl atoms are also present in equal number in both reactant and product side. Thus this obeyed the law of conservation of mass.

Like this, if we see the second option, there also 1 atom of Na is present in reactant and product side and 2 molecules of H is present in reactant and product side, 1 oxygen is present in reactant and product side and 1 Cl is present in reactant and product side. So it also obeys the law of conservation of mass.

But in the third option, P₄ + 5 O₂→ 2 P₄O₁₀, here, there is 4 atoms of P in reactant side but in product side there is (4*2) = 8 atoms of P. Similarly, the number of atoms of oxygen in reactants and product side is also not same. So the third option does not obey the law of conservation of mass.

The fourth option also obeys the law of conservation of mass as the number of atoms of each element is same in both the product and reactant side.

Thus, the third option does not obey the law of conservation of mass.

5 0

3 years ago