Prelab Questions Experiment 1

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A student measured the melting point range of an unknown solid to be 81.9 to 82.3 degrees celsius. a) Is the compound pure? b) Can you identify the compound from Table 2.2? c) If yes, what is the compound? Table 2.2: Solid - Melting Point (Celsius) Benzoic Acid - 122 Acentanilide - 114 Acetamide - 82 Biphenyl - 71 p-Dimethoxybenzene - 59 p-Dichlorobenzene - 54 Benzophenone - 48

The literature value for the melting point of your product was 144-146 °C. Below is the data for 4 students, which student had the purest crystals AND the correct product. Student A: melting point range of 141-142 °C Student B: melting point range of 138-146 °C Student C: melting point range of 150-151 °C Student D: melting point range of 139-143 °C O OB O A O с D

Sample A Sample B Sample C Sample D Observations Sample E Sample F white white Fazzy White (Color and Blue appearance) Crstal crstalwnite Powden crstal Klear State at Room Temperature Sold Solid solid Solid solid liquid Solubility in water Yes Yes Yes No yes y es Color of Solution clear clear blue cleor Clear Conductivity Yes No Yes yes yes Analyze: 1) Can a substance be identified as molecular or ionic based on its state at room temperature? Explain. 2) Can a substance be identified as molecular or ionic based on its solubility? Explain. 3) Can a substance be identified as molecular or ionic based on color? Explain. ilth 4) Can a substance be identified as molecular or ionic based on conductivity of a solution? 5) What was the purpose of measuring the conductivity of distilled water before measuring the conductivity of the different solutions?

Highest melting point Lowest melting point Answer Bank MgF, MgO NaF MAR 29 MacBook Ai 80 DI DD F3 F4 F5 F7 F8 F9 F10 23 2$ & 4 6. 7 8. R Y U P D F J K V N エ ト * の

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Answer the following two questions 1,2

Melting Point of Compounds and Mixtures Yes Melting point measurements Table 1. Melting point of pure compounds Complete melted temperature ("C) Start melting temperature (°C) Pure benzoic acid 123 126 Pure mandelic acid 117 124 Table 2. Melting point for mixtures of benzoic and mandelic acid Complete melted temperature (°C) Start melting temperature (°C) 80:20 mixture (benzoic acid:mandelic acid) 113 117 60:40 mixture (benzoic acid:mandelic acid) 100 109 40:60 mixture (benzoic acid:mandelic acid) 96 104 20:80 mixture (benzoic acid:mandelic acid) 107 113 Calculations and Analysis Determine the midpoint of the starting and completed melting temperatures. Use those temperatures to graph the melting points of the pure compounds and the mixtures. Table view List view Table 3. Melting point analysis Start melting temp ('C) Complete melted temp (°C) Midpoint of melting temp range (°C) Pure benzoic acid 123 126 80:20 mixture (benzoic acid:mandelic acid) 113 117 60:40 mixture (benzoic…

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120- 90 60 30 Time (minutes) 90 What is the melting point of the following substances? Temperature ( C)

What unknown solid sample has a melting point range of 78 degrees celcius to 81 degrees celcius? What is the percent error in its melting point?

Classify each of the following as ionic or molecular.Drag the appropriate items to their respective bins.

A group of students performed a melting point experiment to study the physical properties of ionic and covalent solids. The data collected are shown in the table.  Solid Sample Melting Point (oC)  Time Elapsed (min) Table Sugar (sucrose) 186 18 Table Salt (sodium chloride) 500 (not observed) 30  Paraffin Wax 37 4  Vegetable Lard 50 >5 Using the information contained in the table, what is the BEST explanation for the results?A    The melting point of sodium chloride was not observed because ionic solids do not melt, whereas sugar, wax, and lard melted because they are softer than salt.B    The melting points of covalently bonded solids tend to be lower than ionic solids. The melting point of sucrose was greater than the wax or the lard because sucrose has stronger bonds than wax or lard.C    The melting point of sodium chloride was not observed because ionic solids are composed of positive and negative ions that do not melt; whereas, the…

Filtration of samples A, B, and C show no residue left. After letting them dry in different beakers, SAmple A remains no residues. Sample B shows crystal leftovers, and sample C show brown film on the beaker walls. This means that: a. Two or more samples are heterogenous b. Two or more samples are homogenous c. all sample have 2 or more phases d. all samples are pure

Volatile Liquid Unknowns Liquid Molecular Formula Molar mass Boiling point ('C at 1 atm) (g/mol) Pentane CSH12 72.2 36.2 Acetone C3H6O 58.1 56.5 Methanol CH40 32.0 64.7 Hexane C6H14 86.2 69.0 Ethanol CH6O 46.1 78.5 Questions 1. Calculate the % Error in the molar mass you determined. %Error Ical. Molar mass-Theor. Molar mass! • 100 Theor. Molar mass 2. If the outside of the flask is not dried after vaporizing the liquid, will the unknown's calculated molar mass be too high or too low? Explain. m RT PV

27. Pepper and Salt mixture is a great example of a heterogeneous mixture.   Group of answer choices a)  True b)  False

In a simple set-up, a mixture is heated and the component with the lower boiling point vaporizes first, moves through the condenser, condenses chromatography filtration distillation 1 Ne Sign out

Station 2: Density column In the graduated cylinder, you have molasses, water (blue), corn oil, and ethanol (red). They have the following densities: Substance Molasses Water Corn Oil Ethanol Density 1.45 g/mL 1.0 g/mL 0.92 g/mL 0.79 g/mL Polarity Polar Polar Nonpolar Polar Viscosity High Low Low Low 1. Explain why the column is arranged in the order it is according to density.

In a lab investigation, a student is asked to crush and measure 1 g of sulfur from a larger solid block. The student understands that although the mass of the sample is changing, the melting point will remain the same because he/she knows that ___.

Topic: GRANULES ( I ALREADY ANSWER IT BUT I AM NOT SURE WITH MY ANSWERS, I NEED AN EXPERT TO DOUBLE CHECK MY WORK THANK YOU!!!!) 1. Granules are easier to compress than powders. II. Granules occupies greater volume per unit weight than powders. A. If both statements are TRUE B. If the FIRST statement is only TRUE C. If both statements are FALSE D. If the FIRST statement is only FALSE (MY ANSWER IS A)) 2. Granules prevent the aggregation of powders. II. Moisture and heat labile reagents are preferred in granulated preparations. A. If both statements are TRUE B. If the FIRST statement is only TRUE C. If both statements are FALSE D. If the FIRST statement is only FALSE (MY ANSWER IS C) 3. Wet granulation requires the use of 2 points roller compactors. II. Wet granulation is a prerequisite to avoid the damage of active components in the powder. A. If both statements are TRUE B. If the FIRST statement is only TRUE C. If both statements are FALSE D. If the FIRST statement is only FALSE…

A student is asked to prepare 45.0 mg of a sample to be used in a mixed melting point test. The requested composition of the sample is 65.0 % A and 35.0 % B. What is the mass of compound A needed to prepare the sample?

Geddy and Neil are measuring the melting point of their starting material prior to their lab experiment: despite analyzing the exact same sample from the same jar, they both measured rather different values, with one measuring a melting point of 141.3-153.6°C and the other measuring a melting point of 143.4–144.9°C. Propose a reason explaining the discrepancy.

What unknown solid sample has a melting point range between 119 degrees celsius to 122 degrees celsius? What is the percent error of its melting point?

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0/40 answered physical properties 1 Which of the following would you predict to have the highest boiling point? Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. al heptane b. propane ethane d. nonane Unanswered

[answer with correct answer]   Water exists as a solid (ice), a liquid and a gas (steam). Which state of matter will water be when it is easiest to compress?

Question 10 of 10 (1 point)| Question Attempt: 1 of 1 = 1 = 2 = 3 = 4 = 5 = 6 = 7 = 8 = 9 10 For each pair of compounds listed, check the box next to the one with the higher boiling point. compounds higher boiling point C,H4 CS, Xe Не GeH4 CH, O 2022 McGraw Hill LLC. All Rights Reserved. Terms of Use O O o O

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Question 4 Modified True or False. Analyte interacts with UV -Vis radiation UV radiation is between 200-300 nm and Visible light is at 400-800 nm. Both statements are correct. 1st statement is True. 2nd statement is False. 1st statement is False. 2nd statement is True. O Both statements are False.

If the melting point range obtained from the unknown sample is 121-122 degrees Celsius, can we say that the unknown sample has high purity? Explain.

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Moving to another question will save this response. Question 13 Which of the following is an example of a homogenous mixture? O a chocolate chip cookie O the contents of an IV bag O calamine lotion O whole blood F1 F2 F3 F4 F7 F& ! % 1 3 4 4- %24 %23

If the true melting point for lauric acid is 43.2 oC what is the percent error?