Answer:
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Explanation:
The reaction between NaOH and HCl is as follows
NaOH + HCl ---> NaCl + H₂O
for neutralisation, H⁺ ions react with an equivalent amount of OH⁻ ions.
Number of NaOH moles reacted = 0.270 M/1000 mL/L x 37 mL = 0.00999 mol
number of HCl moles reacted = 0.270 M/1000 mL x 27 mL = 0.00729 mol
HCl reacts with NaOH in 1:1 molar ratio
Number of excess NaOH moles remaining - 0.00999 - 0.00729 = 0.0027 mol
total volume of solution = 37 mL + 27 mL = 64 mL = 0.064 L
Since there's excess OH⁻ ions, we can calculate pOH value first
pOH = - log [OH⁻]
[OH⁻] = 0.0027 mol / 0.064 L = 0.042 mol/L
pOH = -log(0.042 M)
pOH = 1.37
by knowing pOH we can calculate pH using the following equation;
pH + pOH = 14
pH = 14 - 1.37
pH = 12.63
The element first discovered in the sun is the element Helium. This noble gas is the second most abundant element<span> in the universe and was </span>discovered<span> on the </span>sun<span> before it was discovered on the earth. Helium is the result of the nuclear fusion of hydrogen creating thus the mass of energy in the sun.</span>
<u>Answer: </u>One isotope has a percentage abundance of 75.75 % and the percentage abundance of another isotope is 24.24%.
<u>Explanation:</u>
We are given the two stable isotopes of chlorine with their respective masses. The average atomic mass of chlorine is also given.
Average atomic mass of chlorine = 35.45 amu.
Let us assume the fractional abundance of one isotope be 'x' and the fractional abundance for another isotope will be (1 - x) because the total fractional abundance is always equal to 1.
Fractional abundance = x
Mass = 34.97 amu
Fractional abundance = 1 - x
Mass = 36.95 amu
The formula for the calculation of average atomic mass is given by:

Putting values in above equation, we get:


Converting these two fractional abundances into percentage abundances by multiplying it with 100.

Hence, one isotope has a percentage abundance of 75.75 % and the percentage abundance of another isotope is 24.24%.