Answer:

Explanation:
A = Absorbance of solution
E = Molar absorptivity
l = Length of cuvette = 1 cm
c = Concentration of solution
Beer's law is given by

The equation of a straight line is given by

Comparing the above equations we get
Value on
axis = A = Absorbance of solution = 0.23
= Slope of line = El = Molar absorptivity multiplied with length = 
= Value of x axis = c = Concentration of solution
So we get

The molar concentration of the sample is 
Answer:
2 pairs (4 electrons)
Explanation:
In a molecule of oxygen there are 2 oxygen atoms. There are 6 electrons in the outer shells of oxygen atoms. When 2 oxygen atoms form a covalent bond they share their electrons. In a diagram this would be represented by the overlap of the two circles representing the outer shells of both oxygen atoms. If each oxygen atom 'puts forward' 2 electrons into the centre, then 4 will be shared overall for each atom, making both atoms have full outer shells of 8 electrons each. 4 electrons make 2 pairs, hence the answer.
Answer:

Explanation:
From the question we are told that:
pKa for Acetic Acid 
Therefore
For Equal Concentration of acetic acid and acetatic ion

Generally the Henderson's equation for pH value is mathematically given by



