What is the percentage by mass of nacl in a saturated solution of sodium chloride at 50 c?

In this solution we are having two components i.e. NaCl and H₂O. So the %age mass of NaCl is calculated by following formula,

%age mass of NaCl  =  (Mass of NaCl / Mass of NaCl + Mass of H₂O) × 100      (1)

Calculating Mass of NaCl at 50°C;

Solubility of NaCl was searched online and was found 36.69 g / 100 mL of water at 50 °C.

Calculating Mass of 100 mL H₂O at 50°C;

Density of H₂O at 50 °C is 0.988 g/ml, so for 100 mL
As,
                           Density  = Mass / Volume

                           Mass  =  Density × Volume

                           Mass  =  0.988 g/mL × 100 mL

                           Mass  =  98.8 g

Putting Masses of NaCl and H₂O in eq. 1,

              %age mass of NaCl  =  (36.69 g / 36.69 g + 98.8 g) × 100

              %age mass of NaCl  =  (36.69 g / 135.49 g) × 100

              %age mass of NaCl  =  27.07 %

The answer is true for your question.

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

explanation

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.