Potassium dichromate reacts with sulfuric acid to form chromic acid, H₂CrO₄ which is a very strong oxidizing agent. The secondary alcohol, (<em>R</em>)-2-butanol will be oxidized in the presence of chromic acid, but it can only be as oxidized as far as the ketone, which is the product shown, 2-butanone.
Sodium borohydride is a reducing agent that will reduce a ketone or aldehyde to an alcohol. When sodium borohydride reacts with 2-butanone, it reduces it to 2-butanol. However, the alcohol is no longer chiral as it was in the beginning since the sodium borohydride can add a hydride to either face of the carbonyl, which results in a racemic mixture of alcohols. This explains why the product has the same refractive index and boiling point as (<em /><em>R</em>)-2-butanol, however, the product formed would no longer be optically active.
Explanation:
Molar mass
The mass present in one mole of a specific species .
The molar mass of a compound , can easily be calculated as the sum of the all the individual atom multiplied by the number of total atoms .
(a) P₄
Molar mass of of the atoms are -
Phosphorous , P = 31 g/mol
Molecular mass of P₄ = ( 4 * 31 ) = 124 g/mol .
(b) H₂O
Molar mass of of the atoms are -
Hydrogen , H = 1 g/mol
oxygen , O = 16 g/mol.
Molecular mass of H₂O = ( 2 * 1 ) + ( 1 * 16 ) = 18 g/mol
(c) Ca(NO₃)₂
Molar mass of of the atoms are -
calcium , Ca = 40 g/mol
nitrogen, N = 14 g/mol
oxygen , O = 16 g/mol.
Molecular mass of Ca(NO₃)₂ = ( 1 * 40 ) + ( 2 * 14 ) + ( 6 * 16 ) = 164 g/mol.
(d)CH₃CO₂H (acetic acid)
Molar mass of of the atoms are -
Carbon , C = 12 g/mol.
oxygen , O = 16 g/mol.
Hydrogen , H = 1 g/mol
Molecular mass of CH₃CO₂H =( 2 * 12 ) + (2 * 16 ) + (4 * 1 ) = 60 g/mol.
(e) C₁₂H₂₂O₁₁ (sucrose, cane sugar).
Molar mass of of the atoms are -
Carbon , C = 12 g/mol.
oxygen , O = 16 g/mol.
Hydrogen , H = 1 g/mol
Molecular mass of C₁₂H₂₂O₁₁ = (12 * 12 ) + ( 22 * 1 ) + ( 11 * 16 ) = 342 g/mol.
In the given question we need to convert 0.075 meter into centimeter. For this purpose we need to know the relation between meter and centimeter. Then only this problem can be solved and the correct answer reached.
Now we know that
1 meter = 100 centimeter
Then
0.075 meter = [(100/1) * 0.075] centimeter
We know that any number when divided by 1 gives the same number.
So
0.075 meter = (100 * 0.075) centimeter
= (100 * 75/1000) centimeter
= (7500/1000) centimeter
= (75/10) centimeter
= 7.5 centimeter.
So from all the given options the correct answer to the question is 7.5 centimeter.
Answer:
A. 11.1%
B. 0.0291
C. 1.57 M
D. 1.67 m
Explanation:
A.
Mass of KCl (solute): 28.0 g
Mass of water (solvent): 225 g
Mass of solution: 28.0 g + 225 g = 253 g
The mass percent of KCl is:
%KCl = (mass of KCl/mass of solution) × 100%
%KCl = (28.0 g/253 g) × 100%
%KCl = 11.1%
B.
The molar mass of KCl is 74.55 g/mol. The moles of KCl are:
28.0 g × (1 mol/74.55 g) = 0.376 mol
The molar mass of water is 18.02 g/mol. The moles of water are:
225 g × (1 mol/18.02 g) = 12.5 mol
The total number of moles is 0.376 mol + 12.5 mol = 12.9 mol.
The mole fraction of KCl is:
X(KCl) = moles of KCl / total moles
X(KCl) = 0.376 mol / 12.9 mol
X(KCl) = 0.0291
C.
The volume of the solution is 239 mL (0.239 L).
The molarity of KCl is:
M = moles of KCl / liters of solution
M = 0.376 mol / 0.239 L
M = 1.57 M
D.
The molality of KCl is:
m = moles of KCl / kilograms of solvent
m = 0.376 mol / 0.225 kg
m = 1.67 m
