An investigator can collect hairs they observe visually (with tweezers or by hand), and they can also use clear tape to lift non-visible hair from a variety of surfaces, such as clothing. Other methods of hair sample collection include combing and clipping methods.
<u>Answer:</u>
2.07 grams
<u>Explanation:</u>
We know that the molecular mass of
is 138.205 grams.
In order to find out how many grams we need to make 200 mL having a potassium ion concentration of 0.150, we need to find the number of moles first.
M = moles / liters
0.150 = x / 0.200
x = 0.03 moles
Since there are 2 potassium atoms in each molecule of
so we will divide this number by half and multiply it by the molecular mass.
0.03/2 = 0.015 moles
Mass of
needed = 0.015 × 138.205 = 2.07 grams
Question is incomplete, complete question is;
A 34.8 mL solution of
(aq) of an unknown concentration was titrated with 0.15 M of NaOH(aq).

If it takes 20.4 mL of NaOH(aq) to reach the equivalence point of the titration, what is the molarity of
? For your answer, only type in the numerical value with two significant figures. Do NOT include the unit.
Answer:
0.044 M is the molarity of
(aq).
Explanation:
The reaction taking place here is in between acid and base which means that it is a neutralization reaction .
To calculate the concentration of acid, we use the equation given by neutralization reaction:

where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is NaOH.
We are given:

Putting values in above equation, we get:

0.044 M is the molarity of
(aq).
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