- Questions & Answers
- + Post
- Get Expert Help
- Get Coins
- CourseHero Free
Please explain the correct answer to all three questions. Thank you!
Solution11. The titration curve clearly shows that the monoprotic acid used is a very weak acid, as the rise in pH near end-point is not very sharp. The weaker the acid, the slower it will be in absorbing the OH- ions supplied by the NaOH.
Near the end-point the pH will be greater than 7. The indicator used should be such that is color change occur at above 7.
This is true for Thymol blue as well as phenolphthalein.
However, with thymol blue, the range is between 8.0 to 9.6 ( color change from yellow to blue). This might not give the exact end point. The equivalence point might occur slightly above 8 also. This cannot be detected with thymol blue.
With Phenolphthalein, the range is 8.2 to 10. The color change would be from colorless to red. This would be best indicator in this case. Option a)
Solution 12. Calcium Phosphate would exist in the following equilibrium:
Ca3(PO4)2(s) 3 Ca2+(aq) + 2PO43-(aq)
Now, understand that addition of acid (H+) ions would react with phosphate ions as:
PO43- + H+ HPO42- ... and also other reactions are possible with HPO42-
The main point is that phosphate ions are getting consumed by addition of acid. If the equilibrium of calcium phosphate is thus disturbed, it will try to re-establish itself (Le-Chatelier's principle) by producing more phophate ions. The solubility of Calcium phospahte would therefore increase as the equilibrium shift towards right.
Thus option b) is correct
Solution 13. All the processes (except the last one) mentioned are spontaneous process. It is because they do not need any outside intervention.
For example, you do not need to stir the cup of hot milk to dissolve the sugar.(we do it only to make the process faster!, else, it will happen on its own in some time).
A raw banana left on its own will ripen itself.
In Nitrogen formation, entropy is decreased, but the enthalpy of the reaction, due to very stable nitrogen molecule with three triple bonds, the reaction has negative free energy. Thus it is spontaneous.
Similarly, Lightning is formation of NO from nitrogen and Oxygen at very high temperatures. Note that fortunately, this combination does not take place at normal temperature and pressure.
The last one, that is, Formation of CH4 and O2 from CO2 and H2O however needs energy.
Note that spontaneous does not mean that reaction occur rapidly.
Kindly submit feedback if explanation is satisfactory.
Please explain the correct answer to all three questions. Thank you! Incorrect Question 11 0/1 pts...
Please show all work as need and circle the correct answer. Thanks 6. Maleic acid is a diprotic organic acid with the structure shown below. A titration curve was generated when 75.0 mL of a 0.0125 M maleic acid solution was titrated with NaOH. HOOC COOH PH maleic acid o 80 20 40 60 Volume of NaOH (mL) A. (6 pts) What was the approximate concentration of the NaOH solution? B. (3 pts) What is the approximate pka of maleic...
Please explain the correct answer for both questions. Thank you! Incorrect Question 5 0/1 pts A 25.0 mL sample of 0.723 M HCIO4 is titrated with 0.27 M KOH solution. The H30* concentration after the addition of 80.0 mL of KOH is M. (Cl is chlorine, not carbon and iodine) 0.4 3x10-13 1x107 0.7 4x10-2 Incorrect Question 6 0/1 pts What could be the pKof this weak acid according to the titration curve below? Weak Acid Titration Curve PH 10...
EXP #9:Pre-Lab answer question 3, attached below is page two to reference! Instructor Name: Student Name: 3. An unknown solution gives the following sequential results for color when indicators are added (shown below). Using the corresponding color ranges from the table on page 2, estimate the approximate pH range of this unknown solution. Explain. Bluish purple Bromphenol blue: Yellow Methyl Red: Blue Bromothymol Blue: Colorless Phenolpthalein: For a titration, pure indicators are used because the goal is to use an...
Please explain the correct answer for both questions. Thank you! Incorrect Question 7 0/1 pts The concentration of iodide ions in a saturated solution of lead (11) iodide is_ The solubility product constant of Pblz is 1.4x10-8. 3.5x10-9 3.0x10-3 1.5x103 1.4x10-8 3.8x10-4 Incorrect Question 9 0/1 pts The molar solubility of lead () chloride (PbCl2) is 1.6x102 M. What is the Ksp of PbCl2? 4.1x10-6 5.0x10-4 1.6x10-2 3.1x107 1.6x10-5
Answer all assigned questions and problems, and show all work. Determine the pH of (a) a 0.40 MCH3CO2H solution, (b) a solution that is 0.40 MCH3CO2H and 0.20 MNaCH3CO2. (8 points) (Reference: Chang 16.5) Which of the following solutions can act as a buffer? (a) KCl/HCl, (b) KHSO4/H2SO4, (c) KNO2/HNO2.(5 points) (Reference: Chang 16.9) Calculate the pH of the buffer system made up of 0.15 MNH3/0.35 MNH4Cl. (5 points) (Reference: Chang 16.11) The pH of a bicarbonate-carbonic acid buffer is...
Please explain the correct answer. Thank you! Incorrect Question 2 0/1 pts What change will be caused by addition of a small amount of HCl to a solution containing fluoride ions and hydrogen fluoride? (Cl is chlorine, not carbon and iodine) The concentration of hydrogen fluoride will decrease and the concentration of fluoride ions will increase. The fluoride ions will precipitate out of solution as its acid salt. The concentration of hydronium ions will increase significantly. The concentration of fluoride...
Please explain the correct answer to both questions. Thank you! Incorrect Question 19 0/1 pts The value of A Sº for the catalytic hydrogenation of acetylene to ethene, C2H2(g) + H2(g) →C2H4 (g) is_ J/K.mol. Use the following thermodynamic quantities for selected substances at 298.15 K (25°C). Substance AHºf (kJ/mol) AG°f (kJ/mol) S (J/K-mol) 2.84 Carbon C(s, diamond) 1.88 C(s, graphite) 0 C2H2(g) 226.7 C2H4 (g) 52.30 C2H6 (g) -84.68 CO(g) -110.5 CO2 (g) -393.5 209.2 68.11 -32.89 -137.2 -394.4...
please answer and explain why. Thank You! Incorrect Question 3 0/1 pts • How many turns of the Calvin cycle does it take to feed one molecule of glyceraldehyde-3-phosphate into the biosynthesis of glucose? Six One Two Three None of the other answers given
i need help with all these questions please Question 23 4 pts Which of these liquids is most likely to have the lowest (slowest) rate of evaporation (g/min) and why? Select the single best answer. H H H HH :01 IH terbaru H 11 HHH cnc- 7 H H H ica H 나 Hit 4 c B A ΟΟΟΟΟΟ C, because it has the highest molar mass. A, because this molecule has the lowest molar mass.. B, because it has...
Please help me with ALL of these questions. Thank you so much Question 7 0.3 pts The chloroplast is a membrane-bound organelle very similar to the mitochondrion. Both organelles are thought to have been acquired through an endosymbiotic event where a bacterium was engulfed by an ancestral eukaryotic cell and accidentally retained over evolutionary time and evolved into specialized organelles. Which area of the chloroplast is most similar to the inner membrane of the mitochondria such that both areas in...