Actual question from source:-
A 3.96x10-4 M solution of compound A exhibited an absorbance of 0.624 at 238 nm in a 1.000 cm cuvette. A blank had an absorbance of 0.029. The absorbance of an unknown solution of compound A was 0.375. Find the concentration of A in the unknown.
Answer:
Molar absorptivity of compound A = 
Explanation:
According to the Lambert's Beer law:-
Where, A is the absorbance
l is the path length
is the molar absorptivity
c is the concentration.
Given that:-
c = 
Path length = 1.000 cm
Absorbance observed = 0.624
Absorbance blank = 0.029
A = 0.624 - 0.029 = 0.595
So, applying the values in the Lambert Beer's law as shown below:-
<u>Molar absorptivity of compound A = </u>
Answer:
The answer to your question is P = 2.13 atm
Explanation:
Data
Pressure = ?
number of moles = 3.54
Temperature = 376 °K
Volume = 51.2 L
R = 0.08205 atm L/mol°K
Formula
PV = nRT
- Solve for P
P = nRT / V
- Substitution
P = (3.54)(0.08205)(376) / 51.2
- Simplification
P = 109.21 / 51.2
Result
P = 2.13 atm
Answer:
A voltaic cell
Explanation:
A voltaic cell is a device which converts chemical energy to electrical energy. The chemical reactions that take place inside the cell causes electrons to flow from anode to cathode hence, electricity is produced. A simple voltaic cell is made by placing two different metals in contact with an electrolyte separated by a salt bridge. The cathode is the negative electrode while the anode is the positive electrode. It is also called a galvanic cell.
In a voltaic cell having a copper/copper solution half cell, reduction occurs at the cathode. Hence, at the cathode copper II ions accept two electrons and become reduced to ordinary metallic copper. This causes the blue colour of the solution to become discharged (fade) as the cell continues to function.
The answer is (4) Add enough solvent to 30.0 g of solute to make 1.0 L solution. The molarity is calculated using volume of the solution. When solute dissolving, the total volume will change. So the final volume of solution need to be 1.0 L.
