Which atom, O or N, has the greater atomic radius?

Anna [14]

Considering the Hess's Law, the enthalpy change for the reaction is 221.8 kJ/mol.

Hess's Law indicates that the enthalpy change in a chemical reaction will be the same whether it occurs in a single stage or in several stages. That is, the sum of the ∆H of each stage of the reaction will give us a value equal to the ∆H of the reaction when it occurs in a single stage.

In this case you want to calculate the enthalpy change of:

C₂H₄ (g) + 6 F₂ (g) → 2 CF₄ (g) + 4 HF (g)

which occurs in three stages.

You know the following reactions, with their corresponding enthalpies:

Equation 1: H₂ (g) + F₂ (g) → 2 HF (g) ∆H° = -79.2 kJ/mol

Equation 2: C (s) + 2 F₂ (g) → CF₄ (g) ∆H° = 141.3 kJ/mol

Equation 3: 2 C(s) + 2 H₂ (g) → C₂H₄ (g) ∆H° = -97.6 kJ/mol

Because of the way formation reactions are defined, any chemical reaction can be written as a combination of formation reactions, some going forward and some going back.

<h3 /><h3>FIRST STEP</h3>

First, to obtain the enthalpy of the desired chemical reaction you need one mole of C₂H₄ (g) on reactant side and it is present in first equation. Since this equation has one mole of C₂H₄ (g) on the product side, it is necessary to locate it on the reactant side (invert it).

When an equation is inverted, the sign of ΔH° also changes.

<h3>SECOND STEP</h3>

Now, you need 2 moles of CF₄ (g) on the product side. The second equation has 1 mole of CF₄ (g) on the product side, so it is necessary to multiply it by 2 to obtain 2 moles of CF₄ (g).

Since enthalpy is an extensive property, that is, it depends on the amount of matter present, since the equation is multiply by 2, the variation of enthalpy also.

<h3>THIRD STEP</h3>

Finally, you need 4 moles of HF (g) on the product side. The first equation has 2 moles of HF (g) on the product side, so it is necessary to multiply it by 2 to obtain 4 moles of the compound.

Since the equation is multiply by 2, the variation of enthalpy also is multiplied by 2.

<h3>SUMMARY</h3>

In summary, you know that three equations with their corresponding enthalpies are:

Equation 1: 2 H₂ (g) + 2 F₂ (g) → 4 HF (g) ∆H° = -158.4 kJ/mol

Equation 2: 2 C (s) + 4 F₂ (g) → 2 CF₄ (g) ∆H° = 282.6 kJ/mol

Equation 3: C₂H₄ (g) → 2 C(s) + 2 H₂ (g) ∆H° = 97.6 kJ/mol

Adding or canceling the reactants and products as appropriate, and adding the enthalpies algebraically, you obtain:

C₂H₄ (g) + 6 F₂ (g) → 2 CF₄ (g) + 4 HF (g) ΔH°= 221.8 kJ/mol

Finally, the enthalpy change for the reaction is 221.8 kJ/mol.

Learn more about molar enthalpy:

7 0

1 year ago

The specific heat of ethanol is 2.44 J/g ֯C. How many kJ of energy are required to heat 50.0 grams of ethanol from -20 ֯C to 68

Aliun [14]

Answer:

Heat energy required (Q) = 10.736 KJ

Explanation:

Given:

Specific heat of ethanol (C) = 2.44 J/g °C

Mass of ethanol (M) = 50 gram

Initial temperature (T1) = -20°C

Final temperature (T1) = 68°C

Find:

Heat energy required (Q) = ?

Computation:

Change in temperature (ΔT) = 68°C - (-20°C)

Change in temperature (ΔT) = 88°C

Heat energy required (Q) = mC(ΔT)

Heat energy required (Q) = (50)(2.44)(88)

Heat energy required (Q) = 10,736 J

Heat energy required (Q) = 10.736 KJ

5 0

3 years ago

JJ thomson experiment the atomic theory?

olga nikolaevna [1]

Cathode Ray experiment to figure out electrons exist -> atoms can be broken up into subatomic particles

3 0

2 years ago

Magnesium reacts with Oxygen gas forming Magnesium oxide as shown;

LuckyWell [14K]

Molar mass:

O2 = 16 x 2 = 32.0 g/mol Mg = 24 g/mol

<span>2 Mg(s) + O2(g) --->2 MgO(s)
</span>
2 x 24.0 g Mg -------------> 32 g O2
5.00 g Mg -----------------> ( mass of O2)

mass of O2 = 5.00 x 32 / 2 x 24.0

mass of O2 = 160 / 48

= 3.33 g of O2

hope this helps!

5 0

2 years ago

How were the elements in the first periodic table arranged?

Snezhnost [94]

Based on atomic mass

Explanation:

Elements were arranged on the first periodic table based on their atomic masses.

The mass of an atom is made up of the mass of the nucleus which contains the protons and neutrons.

Dimitri Mendeleev was the first person credited for arranging elements periodically.
He was said to have been inspired while playing his game of solitaire on a train.
On his table, he left spaces for the atomic masses of elements not yet discovered.
Today, the periodic table is based on the atomic numbers of elements. This is the number of protons in an atom.

Learn more:

Periodic table brainly.com/question/2690837

#learnwithBrainly

5 0

3 years ago