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Karolina [17]
2 years ago
13

he standard enthalpies of formation for S (g), F (g), SF4 (g), and SF6 (g) are +278.8, +79.0, -775, and -1209 kJ per mole, respe

ctively. What is the energy of the S--F bond WITHOUT using the dissociation energy bond chart. (Step by step proof is needed)
Chemistry
1 answer:
JulsSmile [24]2 years ago
3 0

Answer:

+60.54 kJ/mol

Explanation:

The enthalpy of formation of a compound is the sum of the enthalpies of the formation of its constituents and the bond of them. To form a compound, energy must be lost, so, they're negative.

For SF4, the enthalpy is formed by the energy of one S, two F, and 4 S-F bond (Hb):

H = - (278.8 + 4*79.0 + 4*Hb)

-775 = -(594.8 + 4Hb)

594.8 + 4Hb = 775

4Hb = 180.2

Hb = +45.05 kJ/mol

For SF6, the enthalpy is formed by the energy of one S, six F, and 6 S--F bonds (Hb):

H = -(278.8 + 6*79.0 + 6*Hb)

-1209 = -(752.8 + 6Hb)

752.8 + 6Hb = 1209

6Hb = 456.2

Hb = +76.03 kJ/mol

Thus, the energy of S--F bond must be the average of these two:

(45.05 + 76.03)/2 = +60.54 kJ/mol

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How does the reactivity of nonmetals change as you move from left to right across the periodic table?
Rudiy27

Answer:

Metallic character refers to the level of reactivity of a metal. Non-metallic character relates to the tendency to accept electrons during chemical reactions. Metallic tendency increases going down a group. Non-metallic tendency increases going from left to right across the periodic table.

Explanation:

I hope this helps :)

4 0
2 years ago
A chemist must dilute 97.1 ml of aqueous magnesium fluoride solution until the concentration falls to 389 microMolarity . He'll
mojhsa [17]

Answer:

0.302L

Explanation:

<em>...97.1mL of 1.21m M aqueous magnesium fluoride solution</em>

<em />

In this problem the chemist is disolving a solution from 1.21mM = 1.21x10⁻³M, to 389μM = 389x10⁻⁶M. That means the solution must be diluted:

1.21x10⁻³M / 389x10⁻⁶M = 3.11 times

As the initial volume of the original concentration is 97.1mL, the final volume must be:

97.1mL * 3.11 = 302.0mL =

0.302L

6 0
2 years ago
What type of molecule is acetylacetone?
Vlada [557]

Answer:

c. ketone

Explanation:

the answer is ketone

6 0
2 years ago
I was wondering what the answer for this question would be ?
mixer [17]

Answer:

C. H2O is the base and H3O+ is the conjugate acid

Explanation:

According to Bronsted-Lowry acid-base theory, an acid is a substance that loses an hydrogen ion or proton (H+) while a base is a substance that gains an hydrogen ion (H+) or proton. Furthermore, this theory states that, the molecule formed when an acid donates its proton is called the CONJUGATE BASE, while the molecule formed when the base accepts proton is called CONJUGATE ACID.

In this question, the following equation is given:

NH4+(aq) + H2O(aq) ⇌NH3(aq) + H3O+ (aq)

Water (H2O) is the base in this equation because according to Bronsted-Lowry acid-base theory, it accepts an hydrogen ion (H+) while hydroxonium ion (H3O+) is the conjugate acid.

7 0
2 years ago
A sample of 9.00 grams of aluminum metal is added to an excess of hydrochloric acid. The volume of hydrogen gas produced at stan
marysya [2.9K]

Answer:

The volumen of hydrogen (H) is 11.22 L

Explanation:

The balanced reaction between the aluminum (Al) and the hydrochloric acid (HCl) is:

2Al(s) + 6HCl(l) --> 2AlCl3(ac) + 3H2(g)

It is a reduction-oxidation reaction.

At the beginning we have 9.00 grams of Al what represents an certain amount of moles. Then, we know the molar mass of Al is 26.9815 g/mol, so the moles content in 9.00 g of Al are :

9.00 g Al * (1 mol Al / 26.9815 g Al)= 0.33356 mol Al

Now, we have to conisdered the molar relation between the Al and H2, according to the balanced reaction performed above. That is 2:3 (Al:H2)

Then,

0.33356 mol Al * (3 mol H2/  2mol Al) = 0.50034 mol H2

In this point, we can considered the H2 like a noble gas, because the question ask for standard temperature and pressure (0° C= 273.15K and 1 atm).

Let us remember the noble gases equation

PV=nRT

P: pressure

V: Volumen

n: number of moles

R: gases constant

T: temperature

For the volumen, the equation is:

V= (nRT/P)

Now: V= (0.50034 mol * 0.0821 (L*atm/K*mol) * 273.15 K)/ (1 atm)

         V= 11.22 L

3 0
3 years ago
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