(a)
Interpretation:
The average oxidation states of copper in the materials having formulas
Concept Introduction:
Oxidation state is also known as oxidation number. It is defined as the numbers which are assign to the elements in a chemical combination and number represents the electrons which an atom can share, lose or gain to form
Therefore, transfer of electrons refers to the oxidation state.
(a)
Answer to Problem 132MP
In
In
In
Explanation of Solution
The given material is
According to the rules of oxidation states, oxygen is assigned as oxidation state of -2, yttrium is assigned as oxidation state of +3 and barium is assigned as oxidation state of +2. Now, oxidation state of copper should be determined, since overall charge on the molecule is zero.
Therefore, let x be the oxidation state of copper.
+6 charge is net charge of per unit cell, which is compensated by three Cu atoms with a net charge of
The given material is
According to the rules of oxidation states, oxygen is assigned as oxidation state of -2, yttrium is assigned as oxidation state of +3 and barium is assigned as oxidation state of +2. Now, oxidation state of copper should be determined, since overall charge on the molecule is zero.
Therefore, let x be the oxidation state of copper.
+7 charge is net charge of per unit cell, which is compensated by three Cu atoms with a net charge of
The given material is
According to the rules of oxidation states, oxygen is assigned as oxidation state of -2, yttrium is assigned as oxidation state of +3 and barium is assigned as oxidation state of +2. Now, oxidation state of copper should be determined, since overall charge on the molecule is zero.
Therefore, let x be the oxidation state of copper.
+9 charge is net charge of per unit cell, which is compensated by three Cu atoms with a net charge of
Thus, the average oxidation state of copper in material
The average oxidation state of copper in material
The average oxidation state of copper in material
(b)
Interpretation:
The equations should be balanced which are involved in copper analysis.
Concept Introduction:
The
A reduction or an oxidation reaction is known as half reaction.
Balance all atoms including oxygen and hydrogen atoms are carried out by addition of water molecule (to balance oxygen) and hydrogen ion (to balance hydrogen) in the half reactions. Number of electrons and charge should be balanced after that makes the number of electrons equal in both
(b)
Answer to Problem 132MP
The formula of superconductor is
Oxidation state of copper is +2.
Explanation of Solution
Given information:
A sample of one superconductor treated directly with
A sample of second superconductor is dissolved in acid which converts all copper to
Now, two reactions which are involved in copper analysis is given as:
For first reaction:
The above reaction is separated (oxidation-reduction reaction) as:
Balance all the atoms other than hydrogen and oxygen.
Balance oxygen atoms.
Balance hydrogen atoms.
Balance charge and number of electrons.
Multiply (1) by 2.
Add both equations:
The balanced equation is written as:
For second reaction:
The above reaction is separated (oxidation-reduction reaction) as:
Balance all the atoms other than hydrogen and oxygen.
Balance oxygen atoms.
Balance hydrogen atoms.
Balance charge and number of electrons.
Add both equations:
The balanced equation is written as:
(c)
Interpretation:
The formula of the superconductor sample should be determined along with the average oxidation state of copper in this material.
Concept Introduction:
Mole is SI unit which is used to measure the quantity of the substance. It is the quantity of a substance which contains same number of atoms as present in accurately 12.00 g of carbon-12 is known as mole.
Number of moles of a compound is defined as the ratio of given mass of the compound to the molar or molecular mass of the compound.
The mathematical expression is given by:
Number of moles =
Molarity is defined as the ratio of number of moles to the volume of solution in L.
The mathematical expression is:
(c)
Answer to Problem 132MP
Molarity of
Explanation of Solution
Given information:
In step i,
Volume of
Molarity of
Mass of sample = 562.5 mg
In step ii,
Volume of
Molarity of
Mass of sample = 504.2 mg
The mathematical expression for calculating molarity is:
Rearrange the above formula in terms of number of moles:
For step (i)
Convert the given volume in mL to L.
Since, 1L=1000 mL
Thus, volume in L =
=
Number of moles of
=
For step (ii)
Convert the given volume in mL to L.
Since, 1L=1000 mL
Thus, volume in L =
=
Number of moles of
=
Now, the balanced reaction between
Now, for step (i)
Number of moles of
Now, for step (ii)
Number of moles of
Balanced equation for step (i):
Number of moles of
Number of moles of
Total number of moles =
=
Since, 1 mole of sample has three moles of copper.
Thus,
Number of moles of copper in sample =
=
Molar mass of
=
=
Number of moles =
Put the values,
Now, for step (ii)
Number of moles of copper=
1 mole of sample contains 3 moles of copper.
Thus, number of moles of copper in sample =
=
Number of moles =
Mass of sample = 504.2 mg
Put the values,
Now,
For step (ii)
Add both equations,
The balance combined equation is written as:
Now,
Equate value of molar mass from step (ii) and molar mass from step (i)
Thus, the formula of superconductor is
Now,
According to the rules of oxidation states, oxygen is assigned as oxidation state of -2, yttrium is assigned as oxidation state of +3 and barium is assigned as oxidation state of +2. Now, oxidation state of copper should be determined, since overall charge on the molecule is zero.
Therefore, let x be the oxidation state of copper.
+7 charge is net charge of per unit cell, which is compensated by three Cu atoms with a net charge of
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Chapter 4 Solutions
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