how many moles of H+ are present in0.002087 moles of HCL? What is the percent di
ID: 486151 • Letter: H
Question
how many moles of H+ are present in0.002087 moles of HCL? What is the percent difference betweeen 0.1105 and 0.1099? dau LAB SECTION show ALL calculations and watch significant figures! Must phenolphthalein in acid? 1. What is the color of cocmess 2. What is the color of phenolphthalein in base? 3. (a) write a balanced equaiton for reaction between HCI and NaoH. Include phases. b) How many moles of NaoH are required to neutralize 0.003452 moles of HCI? Show calculations. c) A student accidentally used 0.003452 moles of H2SO4 (rather than HC) for the titration with NaOH. Will this change the number of moles of NaOH required to neutralize the H2SO4? Yes or No Explain your answer. c) How many moles of NaOH are now needed in situation (c)? (Hint: write a balanced equation, include phases). Show calculations 4. How many moles of H+ are present in 0.002087 moles of HCl? Show calculations. 5. What is the percent difference between 0.1105 and 0.1099? Show calculations. 6. If 0.9724 grams of an unknown acid required o 008833 moles of NaoH to neutralize it, what is its gram equivalent weight? 7. To what numerical precision should a buret be read? INSTRUCTOR'S OKExplanation / Answer
1) Since HCl is a strong acid it will dissociate in to H+ & Cl-
moles of H+ = M of HCl x ion/solute
= M of HCl x 1 M of H+/1 M of HCl
= 0.002087 x 1/1
=0.002087
2) Calculate percentage difference
between V1 = 0.1105 and V2 = 0.1099
|V1V2|/(V1+V2)/2×100
= |0.11050.1099|/(0.1105+0.1099)/2×100
= 0.544465%
6) Since OH- and H+ ions react on a 1:1 stoichiometric basis, this means that unknown acid must have produced 0.008833 moles of H+ ion.
Since the equivalent weight of an acid is the number of grams of the acid required to produced 1 mole of H+ ion, the equivalent weight of the unknown acid is given by
equivalent weight of unknown acid = 0.9724/0.008833
= 110.08 g/mol
7) Most of the volumetric glasswares are accurate to a few hundredths of a milliliter and are designed such that a careful operator can reproduce measurements with higher degree of precision. Therefore, measurements made with volumetric glassware like burette are reported to 0.01 mL of the actual reading. Depending on the volumes used, three or four significant figures can be shown in data tables and carried in calculations.
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