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3 years ago

What is the formula unit for a compound made from Fe3+ and oxygen?

Chemistry

2 answers:

Oxana [17]3 years ago

8 0

Answer : The correct option is, $Fe_2O_3$

Explanation :

Formula unit of a compound is defined as the minimum number ratio of ions represented in the compound.

The valency of iron is (+3) and the valency of oxygen is (-2). By the criss-cross method the $Fe^{+3}$ cation combine with the $O^{2-}$ anion, it will give $Fe_2O_3$ .

$Fe^{+3}+O^{2-}\rightarrow Fe_2O_3$

The formula by criss-cross method is shown below.

Alexeev081 [22]3 years ago

6 0

Fe2O3 because O has a -2 charge and Fe and +3, you want the charges to equal each other so if you have 2 Fe with +3 charge the charge becomes 6 if you have 3 O with -2 charge the charge becomes 6.

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4 years ago

With reference to He-4 (or the diagram), explain the term isotopes.

boyakko [2]

Answer:

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3 years ago

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Explanation:

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3 years ago

In which of the following processes is ΔH =ΔE ?

Alecsey [184]

Answer:

c. Two moles of hydrogen iodide gas react to form hydrogen gas and iodine gas in a 40-L container.

Explanation:

The enthalpy (ΔH) is related to the internal energy (ΔE) through the following expressions.

ΔH = ΔE + P.ΔV [1]

ΔH = ΔE + R.T.Δn(gas) [2]

where,

P is the pressure

ΔV is the change in the volume

R is the ideal gas constant

T is the absolute temperature

Δn(gas) is the change in the gaseous moles

When ΔV = 0 or Δn(gas) = 0, ΔH will be equal to ΔE.

In which of the following processes is ΔH = ΔE?

a. Two moles of ammonia gas are cooled from 325 °C to 300 °C at 1.2 atm. NO. When ammonia is cooled, the volume is decreased, that is, ΔV < 0 and ΔH ≠ ΔE.

b. One gram of water is vaporized at 100 °C and 1 atm. NO. The corresponding reaction is: H₂O(l) ⇒ H₂O(g). Δn(gas) = 1 - 0 = 1. Then, ΔH ≠ ΔE.

c. Two moles of hydrogen iodide gas react to form hydrogen gas and iodine gas in a 40-L container. YES. The container has a constant volume (ΔV = 0). Also, the corresponding reaction is: 2 HI(g) ⇄ H₂(g) + I₂(g). Δn(gas) = 2 - 2 = 0. Then, ΔH = ΔE.

d. Calcium carbonate is heated to form calcium oxide and carbon dioxide in a container with variable volume. NO. The corresponding reaction is: CaCO₃(s) ⇒ CaO(s) + CO₂(g). Δn(gas) = 1 - 0 = 1. Then, ΔH ≠ ΔE.

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3 years ago