Mixed Substances Lab Answers

The materials that were used/needed in this experiment were a penny, water, soap, rubbing alcohol, a pipet, and a beaker.

In the last test, we had to test out a mystery powder (powder A, B, C), in its own separate test tube, in order to solve the Sherlock Holmes Mystery. Our group had powder C. When we mixed water in the mystery powder, it did not dissolve. When the litmus paper was put into the test tube it turned blue. When the vinegar was mixed it bubbled/foamed up. When we mixed the iodine solution, there was no reaction and the solution turned to a dark brown/black color. When we mixed in the baking soda there was no reaction and it turned to an even darker color.

A mixture, unlike a compound, can be separated by physical means. There are multiple ways in which a mixture can be separated; furthermore, the ways it can be separated is based on what the mixture is made up of.

Since we obtain an unknown proportion of a mixture, it’s important to mention that a mixture is a result of a combination of two or more pure substances that do not react chemically. The physical properties of a mixture depend on its composition because the amounts of each substance making up a mixture can vary. By taking advantage of the unique physical properties of individual components within a mixture, it should be possible to separate a mixture into its components. Mixtures have the following fundamental properties:

The objective of this experiment will be to combine various substances, liquids and metals, and to observe their behavior when they are combined. The types of reactions observed shall determine the nature of these reactions: physical or chemical.

In experiment 3.11, we found out whether or not a larger amount of a liquid would get hotter when it boils. To answer this, we heated a specific amount of unknown liquid and recorded the temperature every fifteen seconds. In our scatter plot, we were able to find the boiling point of our liquid. We know that the slope of our graphs is when the liquid molecules were moving around and heating up. The plateau of our graph points is where the liquid started to evaporate and boil. This is were we found our boiling point at. Shantel and I decided that our boiling point was about 98º Celsius. If you had another slope in your graph, that was when you were simply heating the leftover gas. The histogram showed us that there were about equal amounts of data in the higher temperature (about 95º Celsius) bins for both 20mL of liquid and 10mL of liquid. Also, in the lower temperature bins (75º to 80º Celsius) there was about equal amount of data for 20mL of liquid and 10mL of liquid. There was 7 pieces of data for 10mL of liquid in the lower bins, and 6 pieces of data for 20mL of liquid. If a larger amount of liquid did have a higher boiling point, the clusters would be organized by volumes or amount. For example, all of the 20mL pieces of data would be in the higher temperature bins, and all of the 10mL pieces of data would be in the lower temperature bins or flipped. Rather, the bins were clustered by identity. The boiling point is a characteristic property.

They ruled this combination out by comparing its physical and chemical properties to those of the mystery mixture. One of the differences between the mystery mixture and the mixture of MgSO4, C6H8O7, and NaHCO3 is during the chemical reaction. During the reaction of the mystery mixture the bubbles and only about one centimeter high. During the reaction of MgSO4, C6H8O7, and NaHCO3, the bubbles were approximately one inch tall. Another difference during the chemical reaction was the time that the two mixtures fizzed. The mystery mixture fizzed for about 3 minutes and 14 seconds. The combination of MgSO4, C6H8O7, and NaHCO3 fizzed for approximately 5 minutes and 47 seconds. Thirdly, the eighth-grade scientists decided to eliminate MgSO4, C6H8O7, and NaHCO3 as a possibility to be the mystery mixture because during the reaction the mystery mixture's temperature was 16.5oC at the end of the reaction. While the combination of MgSO4, C6H8O7, and NaHCO3 ended up at 17.6oC. Finally, the scientist knew that they could rule out the mixture of MgSO4, C6H8O7, and NaHCO3 is because they noticed that the chunks in the mystery mixture were not shiny, but very dull, and the lumps in the mix of MgSO4, C6H8O7, and NaHCO3

A homogeneous mixture is a mixture whose composition is uniform throughout. A heterogeneous is the opposite - its composition is not uniform throughout.

Identifying the three components of the unknown mixture, a 1.5 g sample was obtained and dissolved in 30 mL of diethyl ether. This solution was then poured into a separatory funnel with a funnel with the stopcock closed, and inverted twice so that there would be a formation of different layers in the mixture. In order to extract the base from the mixture, approximately 14 mL of 10% hydrochloric acid was added into the funnel and mixed. To mix the hydrochloric acid thoroughly the funnel was gently shaken with the pressure released by removing the stopper intermittently. The solution then separated into an aqueous layer at the bottom, and an organic layer at the top (containing the acid).1 The aqueous layer (containing the base) was released into an

The cup got colder, was a endothermic reaction, which used up energy from the environment, sucked the heat out.

The objective of this lab was to separate a mixture that consisted of elements and compounds. There are seven ways to separate a mixture which included paper chromatography, filtration, evaporation, simple distillation, fractional distillation, magnetism, and separating funnel. The only methods used in this lab were filtration, evaporation, magnetism, and separating funnel. The method of magnetism was used when the magnet was moved under the mixture to separate the iron. The process of filtration involved the use of a filter paper placed in a filter funnel. The funnel was placed in a beaker and the mixture of water, sand, and sodium chloride was poured into the funnel. The liquid part drained through the filter paper into the beaker, leaving the solid sand particles trapped on the filter. After the water and sodium chloride were in a beaker, the process of evaporation was used. The compound was boiled on a hot plate, which led to the water

After about an hour of reaction time, the mixture was isolated via vacuum filtration and was then acidified with 6 M HCl during the work up step. The reaction mixture was initially basic because of the sodium bicarbonate added during the beginning of the reaction. This was confirmed by a litmus paper test, with the reaction mixture spot showing up green which correlates to a pH of 8. However, the incorporation of HCl into the reaction mixture greatly acidified the solution. The litmus paper was spotted with the resulting reaction mixture and appeared red, which suggests a pH of about 2.

Out of the trials of the experiment, the hypothesis was predicting that the control would have the shortest time, the red composition (75% Water, 25% Corn starch) would have the second shortest time, the yellow mixture (50% Water and 50% Corn starch) would have the second longest time, and the blue fluid (25% Water and 75% Corn starch) would have the longest time. In trial one, the results did not behave in the predicted way because the red mixture took 0.05 seconds longer than the yellow composition. Trials two and five behaved the way the hypothesis predicted. Similarly to trial one, in trial four the red mixture took 0.11 seconds longer than the yellow. Finally, trial three showed that the control took 0.07 seconds longer than the red composition.

Starting our hypothesis was that it was cornstarch, according to all of the data we collected in table 2(example at bottom of page). When we just looked at the substance it had a powder like appearance with no real specific way of being arranged. Then we started with each test of the powder first the simple close up look test using the microscope this showed us basically what we had seen with our eyes in a little more detail from this we found that it was what we had seen a powder like substance with no real arrangement but the only difference was two crystals within the powder. Next we moved on to the more complex test like the vinegar test in this test when the vinegar was mixed with the substance it did not really mix at all the vinegar

This lab was to see chemical reactions with different liquids. This was important to find the unknown substance. The controlled variable was the unknown powder, since it doesn’t change. The independent variable was the liquids. These liquids were vinegar, iodine, and water. Lastly, the dependent variable is the chemical reactions. The reaction was affected by the different liquids. If the liquids are changed then the chemical reactions will be different, because they have different properties, causing the atoms to bond differently.