1.50 g of a weak acid (molar mass 176) is dissolved in 50.0 ml of water, and the resultant solution is titrated with 0.300 m naoh. when 12.5 ml of 0.300 m naoh is added, the ph of the resultant solution is 4.00. calculate ka for this acid.

The dissociation constant of this acid is .

Explanation:

Moles of acid =

Moles of sodium hydroxide:

Moles of sodium hydroxide:

To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:

Initial:        0.008523    0.00375                0

Final:       (0.008523-0.00375)   0              0.00375

Volume of solution = 50.0 mL + 12.5 mL = 62.5 mL = 0.0625 L    (Conversion factor:  1 L = 1000 mL)

To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:

We are given:

= ?

pH = 4.00

Putting values in above equation, we get:

The dissociation constant of this acid is .

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.