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romanna [79]
3 years ago
6

Please help asap!! Need help for problem #2.

Chemistry
1 answer:
mel-nik [20]3 years ago
7 0

Answer:

55.56 amu

Explanation:

Let A, B, C and D represent the four isotopes of iron.

The following data were obtained from the question:

Isotope A (Fe-54):

Mass of A = 53.940 amu

Abundance (A%) = 5.82%

Isotope B (Fe-56):

Mass of B = 55.935 amu

Abundance (B%) = 91.66%

Isotope C (Fe-57):

Mass of C = 56.935 amu

Abundance (C%) = 2.19%

Isotope D (Fe-58):

Mass of D = 57.933 amu

Abundance (D%) = 0.33%

Average atomic mass =.?

The average atomic mass of the iron can obtained as follow:

Average atomic mass = [(mass of A × A%)/100] + [(mass of B × B%)/100] + [(mass of C × C%)/100] + [(mass of D × D%)/100]

Average atomic mass = [(53.940 × 5.82)/100] + [(55.935 × 91.66 )/100] + [(56.935 × 2.19)/100] + [(57.933 × 0.33)/100]

= 2.848 + 51.270 + 1.247 + 0.191

= 55.56 amu

Therefore, the average atomic mass of the iron is 55.56 amu

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Write the balanced equation for the equilibrium reaction for the dissociation ofsilver chloride in water, and write the K expres
Marizza181 [45]

Answer:

See explanation

Explanation:

Hello there!

In this case, since the the concentrations are not given, and not even the Ksp, we can solve this problem by setting up the chemical equation, the equilibrium constant expression and the ICE table only:

AgCl(s)\rightleftharpoons Ag^+(aq)+Cl^-(aq)

Next, the equilibrium expression according to the produced aqueous species as the solid silver chloride is not involved in there:

Ksp=[Ag^+][Cl^-]

And therefore, the ICE table, in which x stands for the molar solubility of the silver chloride:

       \ \ \ \ \ \ \ \ \ \ \ \ \ \ AgCl(s)\rightleftharpoons Ag^+(aq)+Cl^-(aq)

I          -                   0             0

C        -                   +x           +x

E        -                    x             x

Which leads to the following modified equilibrium expression:

Ksp=x^2

Unfortunately, values were not given, and they cannot be arbitrarily assigned or assumed.

Regards!

6 0
3 years ago
139%
GaryK [48]

<u>Answer:</u>

The percent composition of this compound is 94%

<u>Explanation:</u>

The reaction can be formed as

2 \mathrm{Fe}+3 \mathrm{Cl}_{2} \rightarrow 2 \mathrm{FeCl}_{3}

\frac{\text { Weight of } \mathrm{Cl}_{2}}{\text { 3* Molar Mass of } \mathrm{Cl}_{2}}=\frac{\text { Weight of } \mathrm{Fe}}{2 * \text { Molar Mass of Fe }}

\frac{\text { Weight of } \mathrm{Cl}_{2}}{3 *(2 * 35.5)}=\frac{3.56}{2 * 55.8}

\text { Weight of } C l_{2}=\frac{3.56 * 3 * 71}{2 * 55.8}=6.79 \mathrm{g}

\mathrm{n}\left(\mathrm{Cl}_{2}\right)=\mathrm{m}\left(\mathrm{Cl}_{2}\right) / \mathrm{M}\left(\mathrm{Cl}_{2}\right)=6.79 / 71=0.1 \mathrm{m}

\mathrm{n}(\mathrm{Fe})=\mathrm{m}(\mathrm{Fe}) / \mathrm{M}(\mathrm{Fe})=3.56 / 55.8=0.06 \mathrm{m}

Based on no. of iron reacted,  

\mathrm{n}(\text { moles of } \mathrm{Fe})=\mathrm{n}\left(\text { moles of } \mathrm{FeCl}_{3}\right)

n = m/M

\mathrm{m}\left(\mathrm{FeCl}_{3}\right)=\mathrm{n}^{*} \mathrm{M}=0.06^{*} 162.5=9.75 \mathrm{g}

% composition ofFeCl_3  

=  (9.75 / 10.39)^{*} 100

= 94%

6 0
3 years ago
An element A combines with element B. The electrons are transferred from the atom A to the atom B. .
Sloan [31]

(a) The nature of bond between A and B is an ionic bond.

(b) The two main properties of the ionic compounds are:

  • Ionic Compounds have high boiling and melting points as they're very strong and require a lot of energy to break.
  • The electrostatic forces of attraction between oppositely charged ions lead to the formation of ions.

(c) If the ionic compound is dissolved in water, the ions in the solid separate and disperse uniformly

<h3>What is an ionic compound?</h3>

Ionic compounds contain ions and are held together by the attractive forces among the oppositely charged ions.

An ionic bond is formed by the complete transfer of some electrons from one atom to another. The atom losing one or more electrons becomes a cation—a positively charged ion.

In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion.

When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution.

Learn more about the ionic bond here:

brainly.com/question/11527546

#SPJ1

6 0
2 years ago
A chemist dissolves 240mg of pure barium hydroxide in enough water to make up of solution. Calculate the pH of the solution. (Th
goblinko [34]

Answer:

pH = 12.22

Explanation:

<em>... To make up 170mL of solution... The temperature is 25°C...</em>

<em />

The dissolution of Barium Hydroxide, Ba(OH)₂ occurs as follows:

Ba(OH)₂ ⇄ Ba²⁺(aq) + 2OH⁻(aq)

<em>Where 1 mole of barium hydroxide produce 2 moles of hydroxide ion.</em>

<em />

To solve this question we need to convert mass of the hydroxide to moles with its molar mass. Twice these moles are moles of hydroxide ion (Based on the chemical equation). With moles of OH⁻ and the volume we can find [OH⁻] and [H⁺] using Kw. As pH = -log[H⁺], we can solve this problem:

<em>Moles Ba(OH)₂ molar mass: 171.34g/mol</em>

0.240g * (1mol / 171.34g) = 1.4x10⁻³ moles * 2 =

2.80x10⁻³ moles of OH⁻

<em>Molarity [OH⁻] and [H⁺]</em>

2.80x10⁻³ moles of OH⁻ / 0.170L = 0.01648M

As Kw at 25°C is 1x10⁻¹⁴:

Kw = 1x10⁻¹⁴ = [OH⁻] [H⁺]

[H⁺] = Kw / [OH⁻] = 1x10⁻¹⁴/0.01648M = 6.068x10⁻¹³M

<em>pH:</em>

pH = -log [H⁺]

pH = -log [6.068x10⁻¹³M]

<h3>pH = 12.22</h3>
8 0
3 years ago
Please answer the question for the points (10)
amid [387]

Answer:

C

Explanation:

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