Solve these questions. Define the terms molarity, endpoint, and standardization.

Question

Solve these questions. Define the terms molarity, endpoint, and standardization. What is the mole ratio between NaOH and KHP? A student performs a titration using a 25 mL buret. If his initial buret reading is 0.10 mL NaOH and his final reading is 18.50 mL, what is the volume used? The same student used a KMP sample mass of 0.402 g. The molar mass of KHP is 204.2 g/mol. Calculate the following: a. moles KHP used b. moles NaOH used c. Molarity of NaOH How will you know when the reaction is complete?

Explanation / Answer

1.a molarity: numer of moles of solute dissoleved perlitre of solution ia called molarity. M= wt*1000/m.w*volume

b. endpoint: the point at which the reagent and the substance under investigation are chemically equivalent is termed as stoichiometric endpoint or simply" end point"

c. standerdization: it is a process of determining the accurate concentarion of a standard solution by titrating it with with a solution exactly known concentration.

2. moleratio 1:1

3. 18.4 ml is used

4.moles= weight/ molecular weight

= 0.402/ 204.2

=0.002 moles (KHP)

B. moles of NaOH used

mass= volume *density = 18.4*2.13= 39.192 g

moles= 39.192/ 39.997= 0.97 moles (NaOH)

C. CONCENTRATION: 0.97M

5. by using an indicator ( organic dye) , one can identify the colour change of it when reaction is completed

  

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