Molarity = 3.9 * 10 ^ -8
pH = - log (3.9 * 10 ^ -8)
pH = - (-7.40893539)
pH = 7.409 = 7.4 ... Ans
The same number of valence electrons exists in the same family of elements in the periodic table. In finding the answer to this problem, we just have to find the pair that belongs to the same family in the periodic table. The same family means same column. Among these, Oxygen and lead (Pb) are in the same family. This pair is the answer.
Answer is: the percent purity of the sodium bicarbonate is 56.83 %.
1. Chemical reaction: 2NaHCO₃ + H₂SO₄ → 2CO₂ + 2H₂O + Na₂SO₄.
2. m(NaHCO₃) = 3.50 g
n(NaHCO₃) = m(NaHCO₃) ÷ M(NaHCO₃).
n(NaHCO₃) = 3.50 g ÷ 84 g/mol.
n(NaHCO₃) = 0.042 mol.
3. From chemical reaction: n(NaHCO₃) : n(CO₂) = 1 : 1.
n(CO₂) = 0.042 mol.
m(CO₂) = 0.042 mol · 44 g/mol.
m(CO₂) = 1.83 g.
4. the percent purity = 1.04 g/1.83 g ·100%.
the percent purity = 56.8 %.
Answer: 
Explanation:
Firstly we need to know that 
, then we cam make the conversion:
This is the height of Mount Everest in feet
However, we can express it using scientific notation by counting to the left the decimal spaces:
Make sure the equation is always balanced first. (It is balanced for this question already) 6.022 x 10^23 is Avogadro’s number. In one mole of anything there is always 6.022 x 10^23 molecules, formula units, atoms. For one mol of an element/ compound use molar mass (grams).
Multiply everything on the top = 8.61x10^47
Multiple everything on bottom= 1.20x10^24
Divide top and bottom = 7.15x10^23
Answer: 7.15x10^23 mol SO2
