Aspirin (acetylsalicylic acid, C9H8O4) is a weak monoprotic acid. To determine its acid-dissociation constant, a student dissolved 2.00 g of aspirin in 0.600 L of water and measured the pH.

What was the Ka value calculated by the student if thepH of the solution was 2.62?

A 0.100 M solution of ethylamine (C2H5NH2) has a pH of 11.87.

Calculate the Kb for ethylamine.

1. was the value calculated by the student.

2. was the of ethylamine value calculated by the student.

Explanation:

1.

The value of Aspirin solution = 2.62

Moles of s asprin =

Volume of the solution = 0.600 L

The initial concentration of Aspirin  = c =

initially

c       0    0

At equilibrium

(c-x)      x   x

The expression of dissociation constant :

:

was the value calculated by the student.

2.

The value of ethylamine = 11.87

The initial concentration of ethylamine = c = 0.100 M

initially

c                    0    0

At equilibrium

(c-x)                x   x

The expression of dissociation constant :

:

was the of ethylamine value calculated by the student.

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.

a chemical change results in a new substance being formed; whereas a physical change will result in a different state of matter

explanation: