Preparation and standardisation of HCL NaOH solutions Essay Example

Preparation and standardisation of HCL NaOH solutions Essay Purpose of this lab was to prepare solutions of acid base and then standardize them by using the titration method. Then use them to determine the unknown concentration of an acid solution. Titration is a procedure that is used to study the stoichiometry of a reaction. Before we start the lab we have to some pre-lab exercises.The first exercise is to calculate the number of grams of NaOH required to make 250 mL of a .1 M solution of NaOH. When we calculate this we get 1g. Then the second exercise was to calculate the number of milliliters of 1.20 M HCL required to make 100.0 mL of a .100 M solutions of HCL. The answer was 8.33 ml.DATA-Standardization of NaOH SolutionSample 1Sample 2Sample 3Mass of KHP.335 g.320 g.307 gInitial Volume NaOH, Vi(mL)0 mL17.2 mL27.3 mLFinal Volume NaOH, Vf (mL)17.2 mL34.6 mL43.4 mLTotal Volume NaOH used (mL)17.2 mL17.4 ml16.1 mLMoles KHP.0016 mL.0016 mL.0015 mLMoles NaOH.0016 mol.0016 mol.0015 molMolarity NaOH.093 M.092 M.093 MAverage Molarity.093 MStandard ization of HCL SolutionSample 1Sample 2Sample 3Volume of HCL12 mL12 mL12 mLInitial Volume NaOH, Vi0 mL11.8 mL22.8 mLFinal Volume NaOH, Vf11.8 mL22.8 mL34.6 mLMolarity NaOH.093 M.093 M.093 mLMoles NaOH.0001 mol.0102 mol.00109 molMoles HCL.0019.0102 mol.00109 molMolarity of HCL.093 M.093 M.092 MAverage Morality.093 MConcentration of Unknown HCL Solution.Unknown 2Sample 1Sample 2Sample 3Volume of HCL12 mL12 mL12 mLInitial Volume NaOH, Vi (mL)Final Volume NaOH used (mL)16 mL21.2 mL26.6 mLTotal Volume NaOH, used (mL)15 mL5.2 mL5.4 mLMolarity NaOH.093 M.093 M.093 MMoles NaOH.000484 mol.000484 mol.000502 molMolarity of HCL.000484 mol.000484 mol.00502 molMolarity of HCL.040 M.040 M.042AVERAGE MOLARITY .041 MConclusion- The titration methods were use to prepare solutions of acid and base and also to determine the unknown concentration of an acid solution. Average Molarity of the unknown solution was .041 M.Supplementary Questions-1. Using the exact mass of NaOH measured and recorded at the b eginning of the experiment, calculate the molarity 250 mL NaOH solution. How does this compare to the NaOH concentration you calculated using the data in part 4? What could be some reasons for this?1g * 1mol/40g * 1L/.25 L= .1 M It is greater then the concentration in part 4.2. Why were the amounts of distilled water added to the acids not precisely recorded and considered to be irrelevant? This might be because distilled water has no effect on the amount of the acid because the acid is stronger.3. Would the calculated molarity of the HCL solutions be higher or lower or not affected if each of the following occurred. Explain your answersA. The buret containing NaOH was rinsed with distilled water but not rinsed with NaOH before being filled.Reduce NaOH concentration, more NaOH would be used. Therefore molarity of HCL would be more.B. The calculated molarity was too highThe moles of NaOH used would be high. Therefore HCL would be highC. The tip of the NaOH buret contained an air bubb le at the beginning of the titration but not at the end.It would seem like more NaOH was used Therefore HCL higher.4. Suppose you used the base Ca(OH)2 instead of NaOH. What changes would need be made to the calculations of the HCL concentrations?It would have to double because twice as more OH ions are used.

29 Improv Opening Lines to Try

29 Improv Opening Lines to Try Here are 29 opening lines- improv starters- to get two-person improvisations jump-started. Each line is created to give the student actors a sense of the characters and setting for an improvised scene. Directions: Print this page and cut the paper into strips- one line per strip.Put the strips into a â€Å"hat†- a container.Assemble student actors into groups of two scene partners.Explain that one student actor per pair will pick a slip that has an opening line printed on it. That student actor will need to read and memorize the opening line, but will not reveal the line to his or her scene partner- yet. This line will be the first line spoken in the pair’s improv.Have one member of each pair pick a line out of the hat and memorize it.Remind student actors of the classroom improvisation guidelines.Have each pair present their improv.Hold a brief reflection on each improv- â€Å"What can you praise?† â€Å"What might they polish?† Opening Lines Excuse me, ma’am. I need to return this shirt for a refund.Miss, I am afraid I did not order a hot dog for dinner.Look, I know you hate this, but we need at least one good photo of you.So, Jordan, please explain why Paul’s homework was in your backpack.Officer, please, no! Don’t give me a speeding ticket!Do you think Mother would like this crown or the silver one?Oh! It is such an honor to meet you! Could I get your autograph for my daughter?Sir, your suitcase will not fit in the overhead bin.I think our cheer needs a better jump and some words that rhyme with team.Ladies and Gentlemen, please welcome today’s guest- Pat Perkins- an expert on how to organize your desk!Look, my muscles are killing me! Can’t we take a break from this workout?Just rip the paper off! I can’t wait for you to see this totally unique gift!Excuse me, ma’am. Is that dinosaur skeleton real or is it just a model?Well, this is what we’ve been training for- t he Olympics! Are you ready to earn that gold medal?I think these shoes make my feet look far too big. Please get me a different pair. Ugh! All the other parents let their kids see PG-13 movies! You’ve just got to let me go!All you have to do is step-kick-step-kick-step-kick. Now try it with me.Behind us is the U.S. Capitol Building, and over there, you’ll see the Washington Monument.It’s just a little tattoo on my arm! Dad has one! I don’t see why you are so upset!Mr. Higgins, please tell our viewers how you plan to spend your lottery winnings!I understand you were an eyewitness to the skateboard theft. Please tell our viewers what you saw.Oh, I am so sorry, but pumpkin spice latte season ended yesterday! What other drink can I get you?Did you honestly think that a trail of breadcrumbs would help us find our way out of the forest and back to our house?Stop right there. You are not leaving this house dressed like that!Halt right there! You are not leaving this palace dressed like that!Your teacher tells me that your classroom behavior is inappropriate. What is your side of the story?I am so sorry, but your credit card has been declined. I’ll need another form of payment. O  woe! O pity! There is no way we shall ever reach the castle by dark!Ew! I thought you said you could cook!