percent by mass=(mass of solute/ mass of solution)*100 %
mass of solute=58.5 g
density (H₂O)=1 g/cm³*(1000 cm³/1dm³)=1000 g/dm³
mass of solvent (H₂O)=0.5 dm³ * (1000 g/dm³)=500 g
mass of solution=mass of solvent + mass of solut
mass of solution=58.5 g+500 g=558.5 g
% mass=(58.5 g/558.5 g) * 100%=10.47% of Na.
solution: 10.47% of Na.
The molarity is the number of moles in 1 L of the solution.
The mass of NH₃ given - 2.35 g
Molar mass of NH₃ - 17 g/mol
The number of NH₃ moles in 2.35 g - 2.35 g / 17 g/mol = 0.138 mol
The number of moles in 0.05 L solution - 0.138 mol
Therefore number of moles in 1 L - 0.138 mol / 0.05 L x 1L = 2.76 mol
Therefore molarity of NH₃ - 2.76 M
Since Kw= [H⁺][OH⁻], and the concentration of both substances are the same, the equation is now Kw=[H⁺]²
So,
3.31x10⁻¹³ = [H⁺]²
Take the square root= 5.75x10⁻⁷
Then take the negative log to find the pH:
-log(5.75x10⁻⁷) = 6.25
Isoelectronic means equal number of electrons.
O+ is formed when the atom of O loses 1 electron.
The number of electrons of neutral O atom equals its number of protons.
Number of protons identifies the atomic number and position of the element in the periodic table.
The positon of O in the periodic table is A = 8, so it has 8 electrons and O+ has 8 - 1 = 7 electrons.
The neutral atom with one electron less than O is of the element to the left of O in the periodic table (A = 7). That element is N.
Therefore, the neutral atom isoelectronic with O+ is N (both have 7 electrons).
