1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Simora [160]
3 years ago
15

32. A sample of potassium is composed of 23% K-39, 48% K-40 and the remainder K-41. Calculate the average mass

Chemistry
1 answer:
mario62 [17]3 years ago
7 0

Answer:

40.06 amu.

Explanation:

From the question given above, the following data were obtained:

Isotope A (K-39)

Mass of A = 39 amu

Abundance of A = 23%

Isotope B (K-40)

Mass of B = 40 amu

Abundance of B = 48%

Isotope C (K-41)

Mass of C = 41 amu

Abundance of C = 100 – (23 + 48)

Abundance of C = 100 – 71

Abundance of C = 29%

Average mass =?

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

= [(39 × 23)/100] + [(40 × 48)/100] + [(41 × 29)/100]

= 8.97 + 19.2 + 11.89

= 40.06 amu

Thus, the average mass of potassium is 40.06 amu

You might be interested in
Calculate the equilibrium constant for the reaction: 2 Cr + 3 Pb2+ ----> 3 Pb + 2 Cr3+ at 25oC. Eocell = 0.61 V
sattari [20]

Answer:

The value is  K  =  8*10^{61}

Explanation:

From the question we are told that

    The equation is  2 Cr  +  3Pb^{2+} \to 3Pb + 2Cr^{3+}

     The  temperature is  T = 25^oC =  298 K   [room  \ temperature ]

     The  emf at standard condition is  E^o_{cell}  =  0.61 \  V

Generally at the cathode

      3Pb^{2+}(aq) + 6 e- --> 3Pb(s)

  At the anode

      2Cr^{3+} + 6e^- \to  2Cr

Generally for an  electrochemical reaction, at room temperature the Gibbs free energy is mathematically represented as  

       G =  n*  F *  E^o_{cell}

Here  n  is  the no of electron  with value n = 6

       F  is  the Faraday's constant with value 96487 J/V

  =>   G =  6  * 96487 *  0.61

  =>   G = 3.5 *10^{5} \  J

This Gibbs free energy can also be represented mathematically as

       G =  RTlogK

Here  R  is the cell constant with value 8.314J/K

           K is the equilibrium constant

From above

=>  K  =  antilog^{\frac{G}{ RT} }

Generally  antilog =  2.718

=>K  =  2.718^{\frac{3.5 *10^5}{ 8.314* 298} }

=>   K  =  8*10^{61}

       

         

       

         

6 0
3 years ago
Which one is the answer?
nadya68 [22]
I would go with C because that seems like the best answer choice
3 0
3 years ago
A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion. B. If both Assertion &amp
Neporo4naja [7]

Answer:

C. If Assertion is true statement but Reason is false.

Explanation:

The burning of magnesium in air produces magnesium oxide as shown by the equation;

2Mg(s) + O2(g) -----> 2MgO(s)

The magnesium oxide solid is recovered as a white ash. This is a typical example of an oxidation reaction which is also a combustion reaction.

The reason has nothing at all to do with the assertion hence the answer given.

Magnesium oxide is basic just like the oxides of other metals and dissolves in water to yield an alkali.

8 0
3 years ago
Read 2 more answers
which of the following chemical symbol is that of an element with six electrons in the outermost shell a)Ca b)Cl c)Ne d)S​
nydimaria [60]
Hey there!

Sulphur is the element which has 6 electrons in the outermost shell.

WhereasCalcium,Neon have 2 and chlorine has 7.

Hope this explanation helps you :)
Have a good day :)
5 0
2 years ago
Read 2 more answers
Which row in the table shows how many electrons there could be in the outer shell of an atom of V? ​
Amanda [17]

Answer:

Explanation:

The element V forms acidic oxide so it must be non- metal because oxides of non metal forms acidic oxide like sulphur ( s ) or chlorine ( Cl₂ )

sulphur forms SO₂ or SO₃ . Chlorine forms acidic oxide like Cl₂O₇ , Cl₂O₃ etc

These oxides are covalent compounds .

So V may have 6 or 7 electrons in the outermost orbit .

Hence option D is the right answer.

6 0
3 years ago
Other questions:
  • Calculating grams:
    13·1 answer
  • Choose the best option for the precursor to the tosylate intermediate Design a synthesis of cis-2-methylcyclopentyl acetate from
    14·1 answer
  • What is the correct name for the compound with the formula CrPO4 and why
    8·2 answers
  • Hydrogen has an average atomic mass of 1.008 amu and has 3 known isotopes
    11·1 answer
  • Which of these is true for the electrons of an atom? Choose
    5·1 answer
  • 4 Sedimentary rock forms in areas where - A. magma flows freely B.tiny sediments get deposited C.rock matter is cooled​
    10·1 answer
  • every spring has an equilibrium position which statement describe a spring at it equilibruim position?
    12·1 answer
  • Plz help!<br><br> What must change in order to change the amount of power?
    8·1 answer
  • ¿por qué la conducción ocurre más lentamente en los gases que en los sólidos?​
    12·1 answer
  • On this number line, zero represents sea level. Plot the following points based on the description provided by dragging and drop
    15·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!