A0.500-l sample of h₂so₄ solution was analyzed by taking a 100.0ml aliquot and adding ml of . after the reaction occurred, an excess of ions remained in the solution. the excess base required ml of for neutralization. calculate the molarity of the original sample of h₂so₄. sulfuric acid has two acidic hydrogens.

The molarity of the original sample of H2SO4 is 0.009289 M

Explanation:

Step 1:  The balanced equation

H2SO4 + 2NaOH → Na2SO4 + 2H2O

Step 2: Calculating moles of NaOH

moles of NaOH = Molarity of NaOH * Volume of NaOH

moles of NaOH = 0.213 M * 50*10^-3 L

moles of NaOH = 0.01065 moles

Step 3: Calculating moles of HCL

HCl + NaOH → NaCl + H2O

13.21 mL of 0.103 M HCl

moles of HCl = molarity of HCl * Volume of HCl

moles of HCl = 0.103M * 13.21 *10^-3 L

moles of HCl =0.00136 moles

Step 4: Calculating moles of NaOH in excess

For 1 mole of HCl consumed there is 1 mole of NaOH needed to produce 1 mole of NaCl and 1 mole of H2O

For 0.00136 moles of HCl consumed, there is also 0.00136 moles of NaOH needed. Those are 0.00136 moles NaOH in excess.

Step 5: Calculating moles of NaOH reacted

0.01065 moles - 0.00136 moles = 0.009289 moles of NaOH reacted

Step 6: Calculating moles of H2SO4

There is 2 moles of NaOH consumed per 1 mole of H2SO4 consumed.

For 0.009289 moles of NaOH reacted, there is needed 0.009289/2 moles = 0.0046445 moles of H2SO4

Step 7: Calculating  molarity of H2SO4

Molarity of H2SO4 = moles of H2SO4 / volume of H2SO4

Molarity of H2SO4 = 0.0046445 / 0.5L = 0.009289 M

The molarity of the original sample of H2SO4 is 0.009289 M

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.