What Is The Percent Composition Of The Initial Unknown Mixture

This lab was conducted in order to determine the melting points of five samples: pure urea, pure trans-cinnamic acid, 90% Urea and 10% trans-cinnamic acid, 50% Urea and 50% trans-cinnamic acid, and 10% Urea and 90% trans-cinnamic acid. The melting points of the substances listed above were obtained by placing 1-2mm samples of each substance in a Mel Temp. From the obtained melting points, a binary phase diagram was created.

The results in Table 1 from part 1 of the experiment are accurate in melting point ranges for each compound. The samples went from a powdery white to a clear liquid. Urea is a little bit higher than from its melting point range of 132°C-133°C and trans-cinnamic acid is in its melting point range of 132°C-135°C. They are both pure compounds because they stayed relatively close to their melting point ranges. The 50/50 mixture has a lower melting point and a broader melting point range because each compound acts as an impurity in the other. The results in Table 2 from part 2 of the experiment have higher melting points than their supposed melting point range. The samples went from a powdery white to a clear liquid. The unknown 8 compound was guessed to be maleic acid since its melting point was in the range 137°C-140°C. For the final trial, however, both unknown 8 and maleic acid had higher melting points out of the range and the 50/50 mixture melted first. This was because the maleic acid used was made from two different salts causing the melting point to be slightly off. In this case, maleic acid is the correct compound of unknown 8 and the melting points are fine.

They ended up being strong and weak bases and this was determined through a pH paper test as well as a flame test. The pH test determined what the pH was and if they were acids or bases and the flame test determined the cation of the substance. The strong base was Potassium Hydroxide (KOH) with a pH of 14. The weak base was Sodium Acetate (NaCH3OO) with a pH of 9. The equivalence point of a chemical reaction is when the chemical equivalent amount of acids and bases have been mixed. For this reaction this point was 19.35 mL of titrant for the strong base and 23.5 mL of titrant for the weak base. While the end point is the point at which a titration is complete, indicated by a color change. This occurred around 19.65 mL of titrant for the strong base and around 25.70 for the weak base. Possible errors in this experiment could include misreading the buret, if one is not accurate it can change the results. Also if the pH meter was not calibrated correctly then the readings for the pH would be incorrect because the wrong pH would be given. If this experiment could be redone then making sure the directions are read carefully would be a number one priority because at times it became confusing, as well as going slow on the titrations so that the readings are

The appearance is stated to be monoclinic crystals. When the substances melted completed, it went from solids to liquids.In Part 1, the melting point range of Urea was 132.5-133.5°C. It had a precise melting point in comparison to the given melting points. The melting point range of Trans-Cinnamic Acid had a melting range of 132.5-133.6°C. The Trans-Cinnamic Acid also had a precise melting point in comparison to the given information. The mixture of the two had an ending melting point of 129°C. The starting point of the mixture was not taken because the start of the melting point was missed. The starting temperature in Part 1 was 120°C, the ramp was 2, and the ending temperature was 190°C. In Part A of Part 2, the Unknown #2 had a melting range of 121-128.4°C. In Part A of Part 2, the starting temperature was 60°C, the ramp was 10, and the ending temperature was 170°C. In Part B of Part 2, the Unknown #2 had a melting range of 122-126.8°C. Succinimide had a melting range of

Our lab group’s goal for the experiment was identifying two mystery compounds, labeled “X” and “Y”. Through multiple trials, we first built Compound Y by using hydrochloric acid on compound X. We put Compound X under a small flame using a bunsen burner to test the existence of chlorine. After we created Compound Y, our group then found the melting point on both compounds and examined the pH properties and solubility of them. This is how we discovered the empirical formula of X and Y. We titrated the two compounds and determined their gram equivalent weights, found the molar weight by cooling the compounds at freezing point, and finally examined the mass and Infrared spectra to analyze the structure. During our experiment, we discovered both

Although the amount recovered was high, the crystals still had a yellow color, showing that impurities remained in the sample. However, the melting point was within the range of the acid identified. Conclusion: The experiment determined that the unknown sample was phthalic acid due to the melting point of 208.9 degrees Celsius. The correction of the machine was found to be 0.3 degrees Celsius, and it was machine #5.

First the molalities were determined by using Equation 1. The average freezing point, ΔTf, of unknown 1 solution was -2.4 degrees Celsius and for unknown 2 it was -4.8 degrees Celsius. The kf value was 1.86 °C/m which was a given value. The van’t Hoff factor, i, was 2 because unknown 1 and unknown 2 both disassociate into two ions due to them both being soluble. In the second step, the unknown number of moles of each unknown was determined by using molality.

Using a Digi Melt to find the melting point, then determining an appropriate solvent, the identity of an unknown solid was found, dissolved, gravity filtrated, and recrystallized to produce a pure solid. By preforming a boiling point test with a thermometer, capillary tube, and water bath, the identity of an unknown liquid was discovered

D - #5: What can you say about the relative melting points of the two substances?

The percent yield of the crude product from experiment seven was 77.6%. The melting point of the crude product was 100 ° C – 119.2 ° C. The melting point range was 19.2 ° C. The percent yield of the pure product from experiment seven was 63.2%. The melting point was 100° C – 108.2 °C. The melting point range was 8.2 ° C. The percent yield of benzilic acid from experiment 8 was 66.9%. The melting point was 139.9° C – 143.3 °C. The melting point range was 3.4 °C. According to PubChem, the melting point of benzilic acid is 150 °C. The reason why the experimental melting point of benzilic acid is lower than the literature value is because there might have been some impurities in the benzilic acid. The reason why there might have been impurities in the benzilic acid is because the crystals might not have been rinsed off with enough water or they were not dried under the vacuum long

The purpose or aim of this investigation is to explore and compare the melting points and boiling points of primary, secondary, and

The melting point of a product is an index of its purity. The closer the observed melting point is to the literature value, the more pure the product. Additionally, the range of the observed product

The purpose of this project is to identify an unknown organic acid (X) by conducting various experiments to determine the acid’s unique properties. By determining selected constant properties of the unknown and then comparing these properties to the constant properties of known substances, it is possible to identify an unknown substance. The properties used to identify the unknown must be intensive, or independent of amount. Both chemical properties and physical properties are intensive properties used in determining the identity of an unknown (Maserton, p. 15).

Conclusion: I have determined that Unknown E is Acetanilide. The melting point of the mixtures was very close to the melting point of plain Unknown E. The 2-Chloracetamide and Unknown E’s mixture had to high of a melting point. Based on my results and observations I would conclude that Unknown E is Acetanilide.

First is the recrystallization of methanol. Recrystallization is a purification technique. The properties of the solvent to be used are it must have a low boiling point, must not react with the product, and the product must not be toxic.