Lab 1 Intro Lab Assignment Fall 2018-1

Describe the results from the neutralisation experiment. Use your knowledge of chemistry to explain the neutralisation of an acid with a base.   (*Note- results are provided in the photo)

Solubility is the ability to dissolve certain substances(solutes) into a solvent. You are a student in Mrs. Bateast's Chemistry class and you were given the assignment to compare solubilities of salt in different solvents at different temperatures. You added salt at a consistent rate and amount until you reached the point of full saturation. The amount added to each solvent at saturation was recorded. The results of the experiment are shown in the tables: Table 1: 20 °C Mass of Salt at Saturation 43 g 38 g 0.01 g 3 g Solvent Water Ethanol Hexane Dichloromethane Table 2: 35 °C Mass of Salt at Saturation 52 g 45 g 0.02 g 4 g Solvent Water Ethanol Нехane Dichloromethane Using CER and your knowledge from data listed above, if the temperature of ethanol solution increased by an additional 10 degrees, what would happen? Construct a line graph is required as well.

Solubility is the ability to dissolve certain substances(solutes) into a solvent. You are a student in Mrs. Bateast's Chemistry class and you were given the assignment to compare solubilities of salt in different solvents at different temperatures. You added salt at a consistent rate and amount until you reached the point of full saturation. The amount added to each solvent at saturation was recorded. The results of the experiment are shown in the tables: Table 1: 20 °C Mass of Salt at Saturation 43 g 38 g 0.01 g 3 g Solvent Water Ethanol Hexane Dichloromethane Table 2: 35 °C Solvent Water Ethanol Mass of Salt at Saturation 52 g 45 g 0.02 g 4g Нехane Dichloromethane Using CER and your knowledge from data listed above, if the temperature of ethanol solution increased by an additional 10 degrees, what would happen? Construct a line graph is required as well.

13. A chemistry student offers a possible improvement to this lab. Since one goal of this lab is to determine the mass of the precipitate produced, wouldn't it be possible to measure the mass of an empty beaker, mix the solutions, and boil off the water until it is entirely evaporated, leaving only solid behind? Then the beaker with the precipitate could be weighed, and the difference between this mass and that of the empty beaker would be the mass of the precipitate. This would eliminate the need for the filtration step. Explain why this is a poor suggestion. Remember to check your reasoning on this question and all other questions with your instructor.

when doing a test to find the molarity of solution of hydrochloric acid, the following results were obtained. The actual molarity of the solution is 1.00 molar.Molarity1.45 1.44 1.46a. both accurate and preciseb. both inaccurate and imprecisec. accurate but imprecised. precise but inaccurate

Suppose a student performed a similar standardization titration experiment using the data in the table here. What is the exact concentration of the NaOH solution? The molar mass of benzoic acid is 122.12 g/mol. mass of NaOH (g) 0.400 volume of NaOH solution (mL) 200.00 mass of benzoic acid (g) 0.158 volume of benzoic acid solution 100.00 (mL) volume of NaOH dispensed (mL) 27.84 Select one: 0.0129 M 0.0465 M 0.1240 M 0.0500 M

A student makes a standard solution of potassium hydroxide by adding 14.555 g to 500.0 mL of water. Answer the following questions, being sure to include units and remember sig figs. Include a picture of your work at the end of this worksheet. What is the concentration of this standard solution? If the student pours out a 15.6 mL sample of this solution, how many moles of potassium hydroxide does the student have in the sample?

3. Solubility data for copper(II) nitrate (Cu(NO3)2) and potassium nitrate (KNO3) at different temperatures is shown below. The values are for grams of compound per 10 milliliters of water. 0°C 20°C 40°C 60°C 80°C 100°C Cu(NO3)2 8.35 12.5 16.3 18.2 20.8 24.7 KNO3 1.3 3.2 6.4 11.0 16.9 24.6 Remember that the solubility of a compound refers the maximum amount of compound that can be dissolved in a particular solvent at a particular temperature. So for example, the maximum amount of copper(II) nitrate that can be dissolved in 10 mL of water at 80°C is 20.8 grams, and the maximum amount of potassium nitrate that can be dissolved in 10 mL of water at 80°C is 16.9 grams. a. How much potassium nitrate could you dissolve in 25 milliliters of water at 60°C based on the data in the table above? (Hint: use the solubility as a conversion factor in the calculation.) b. Could you dissolve 3.0 grams of potassium nitrate in 5 milliliters of water at 60°C? Indicate Yes or No. Explain your answer below.

The equation for the reaction of KHP and NaOH shows a 1:1 ratio for the two reactants. Experimentally, how do you know that the base solution that you delivered from the burette had just as many moles as were in the KHP sample that you weighed out in the beginning of the experiment?

II. Analysis Solubility curves is a graphical relationship between the solubility and temperature. The solubility curve plots the changes of the solubility of a solid at different temperatures in a solvent. On a graph, the variations in temperature are plotted on the X-axis and the solubility is plotted on the Y-axis. The solubility of the solid in a particular solvent is defined as the number of grams of solute needed to saturate 100 g of solvent at a particular temperature. The solubility curves given below describes the solubility of various substance/s at different temperature. Interpret the curves and answer the question that follows. Solubility Curves 150 140 130 120 NANO, KNO 110 100 90 80 HC NH.CI 70 60 KCI NH3 50 40 Naci 30 KCIO, 20 10 So, 10 20 30 40 50 60 70 80 90 100 Temperature °C In general, how does temperature affect solubility? Grams of solute / 100 g H,O

Will the calculated Molarity of NaOH be too high or too low or unaffected if the following happen: When you answer the question, consider how the situation affects the calculation of molarity of NaOH and moles NaOH, which is calculated from the mass of KHP. For each answer, you must supply a clear explanation for your answer. Often times, students will restate the facts rather than explaining why they chose the answer they chose. a) You add the weighed KHP to a flask containing a 60mL of water rather than 50 mL of water. Explain. Your answer must contain a well-thought-out and clearly written explanation. b) The buret is still wet with water on the inside when you add your NaOH solution. Explain c) The KHP is wet when you weigh it. Explain. d) You titrate past the equivalence point by 0.50mL Answer a-d

You dilute the river water 10 times for the analysis of SDS concentration. The instrument measures an average molar concentration of SDS in the diluted river water to be 1.689 10-4 mol/L. The molar mass of SDS is 288.4 g/mol. What is the mass concentration of SDS in the original river water? 4.87 10-1 g/L 4.87 102 g/L 5.86 106 g/L 5.86 10-5 g/L