Tonicity with gummy bears

pdf

School

University of British Columbia *

*We aren’t endorsed by this school

Course

200

Subject

Chemistry

Date

Feb 20, 2024

Type

pdf

Pages

Uploaded by CorporalMetalRaccoon34

Hypothesis: If the concentration of saline solution is increased then the gummy bear will decrease in mass (g) and the solution’s volume(mL) decrease. This will happen because, in a hypertonic solution, the solution outside the cell is more concentrated than inside and this causes water to leave the cell, and the cell will shrink . Variables: Independent variable: ❖ Independent variables in this experiment are distilled water concentration in each solution and saturated NaCl. The change in tonicity of each solution. Dependent: ❖ The dependent variable is basically the physical change in the gummy bear. ❖ Change in color of the solution ❖ Change in size centimeters, weight grams ❖ The shape of the gummy bear ❖ The tonicity change in each of the gummy bears ❖ Change in volume of each NaCl and water solution Controlled variable: ❖ Temperature of solution (room temperature) ❖ The Same volume of solution which is 50 mL ❖ The Same type of gummy bear is used (size and color and similar weight) ❖ The same type of water used in each solution (distilled water) ❖ The measuring tools were the same. ❖ The air pressure was the same throughout the experiment Experimental control: ❖ The experimental control is the gummy bear that has been not touched and no solution and distilled water have been added to the gummy bear. The experimental control is going to be compared to the rest of the gummy bears in the solution. Materials: ❖ Safety goggles (one pair) ❖ Graduated cylinder (one) ❖ Beaker (50mL)(one used only) ❖ Ruler (one) ❖ Marker (one) ❖ Pieces of type (Five pieces) ❖ Gummy bears of the same color (Red color)(6 pieces) ❖ 0% 50mL of distilled water ❖ 20% 40mL of distilled water, ❖ 10 mL of saline solution ❖ 40% 30 mL of distilled ❖ 20 mL of saline solution ❖ 60% 20mL of distilled water ❖ 30 mL of saline solution

❖ 80% 10 mL of distilled water ❖ 40 mL of saline solution ❖ Electronic balance (one) ❖ Spoon (one) ❖ Pipette (one) ❖ Paper towel Procedure: 1. Measured and weighed each of the six gummy bears. 2. Created before, during, and after observations table of values. 3. Labeled each beaker using tape based on the different concentrations listed in the materials. 4. Placed five of the gummy bears in different concentrations of solutions and left one gummy bear untouched. 5. Measured the volume of each solution and wrote measurements in the table of values. 6. Let each gummy bear sit in each solution for one day. 7. Measured each volume of the solutions once again the next day using a graduated cylinder. 8. Carefully took out each gummy bear not separating it and made sure no water was attached to each one. 9. Measured the weight of each gummy bear to determine the tonicity. 10. Recorded final before and after qualitative and quantitative observations and compared before, during, and after values. Data table:

Each Solution of gummy bears Data mass(g) Length( cm) volume (mL) of the gummy bear before the experiment: Data mass(g) Length( cm) volume (mL) of the gummy bear after the experiment: A (0%: 50 mL of distilled water) Mass =2.28g Length=2.4 cm Volume of beaker =50 mL Mass =7.76 g Length=3.7 cm Volume of beaker= 40 mL B (20%: 40 mL of distilled water, 10 mL of saline solution) Mass =2.28g Length=2.4 cm Volume of beaker =50 mL Mass=2.79g Length=3cm Volume Of beaker =46mL C (40%: 30 mL of distilled water, 20 mL of saline solution) Mass =2.28g Length=2.4 cm Volume of beaker =50 mL Mass=0.5g Length=0.7cm Volume of beaker=48mL D (60%: 20 mL of distilled water, 30 mL of saline solution) Mass =2.28g Length=2.4 cm Volume of beaker =50 mL Mass=0 g Length=0 cm Volume of beaker =49 mL E (80%: 10 mL of distilled water, 40 mL of saline solution) Mass =2.28g Length=2.4 cm Volume of beaker =50 mL Mass=1.46 g Length=2.3 cm Volume of beaker=51.5 mL F) Untouched gummy bears Mass =2.28g Length=2.4 cm Volume of beaker with no gummy bear in it =50 mL Mass=2.28g Length=2.4cm Volume of beaker with no gummy bear in it =49.5mL Observation of the gummy bears in each different solution: Before the experiment After the experiment

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Solution A The red gummy bear used was dried up at first or one can say it was dehydrated. The colour was dark red. The distilled water was colourless. The red gummy bear increased in size and its shape and was flabby. The colour changed to light orange. When the gummy bear is dropped in the water there are bubbles formed around it. The distilled water stayed colourless after one day. Solution B The red gummy bear looked dry and did not look like a normal gummy bear. It looked old and had a hard layer on the surface. The distilled saline solutions were colourless The red gummy bear increased in size but compared to gummy bear A it did not increase as much. In the beaker some parts of the gummy bear fell off. The gummy bear felt like it had more liquid inside of it. The gummy bear's colour was transparent and it had a tawny colour to itself. The distilled water turned an orange colour because of the parts that fell off. Solution C The red gummy bear was red and dry and looked dehydrated. The surface of it was hard. The distilled water and saline solution was colourless. The red gummy bear's size is very small compared to the other two, the red gummy bear lost its texture and its shape and the colour is transparent and very light orange. The liquid part of the solution turned into an orange colour. Solution D The red gummy bear colour was red and it looked dehydrated. The surface of the red gummy bear was hard. The distilled water and saline solution was colourless. The red gummy bear completely dissolved and there was no sign of a physical gummy bear. The distilled water and saline solution turned into orangy color. There are tiny particles of gelatin in the solution and it is barely noticeable. Some very small bubbles were formed around the edge of the beaker. Solution E At first the red gummy bear's colour was red and it looked dry and dehydrated. The surface of the gummy bear was hard. The saline solution and distilled water were colourless The red gummy bear did not increase as much as others. The size of the gummy bear looked the same as before the experiment was done. The colour turned lighter like a pinky colour and it kept its shape but the texture was different and was very slimy. The distilled water and saline solution colour were kept the same. Untouched gummy bear F ( Controlled gummy bear the one that we do not change at all) The red gummy bear was had a dark red colour and it looked dry and dehydrated and had a hard surface No change was done so it was the same Calculations: ● Percentage change in mass= x100% ??−?𝑖 ?𝑖 Percentage change in mass (g) for each gummy bear A solution x 100%= increases 240% 7.76−2.28? 2.28

B solution x100%= increases 22% 2.79?−2.28? 2.28? C solution x100%= decreases 78% 0.5−2.28? 2.28 D solution x100%=decreases 100% 0 ?−2.28? 2.28 ? E solution x100%= decreases 36% 1.46−2.28? 2.28? F solution x100%= It stays the same or 0% change 2.28−2.28 2.28 ● Percentage change in volume in (mL) for each beaker x100% 𝑉?−𝑣𝑖 𝑣𝑖 A solution x100%= decreases 20% 40 𝑚?− 50 𝑚? 50 𝑚? B solution x100%= decreases 8% 46 𝑚?−50𝑚? 50𝑚? C solution x100%= decreases 4% 48𝑚?−50𝑚? 50𝑚? D solution x100%= decreases 2% 49𝑚?−50𝑚? 50𝑚? E solution x100%= increase 3% 51.5𝑚?−50𝑚? 50𝑚? F solution ( Water left with no gummy bear) x100% decreases 1% which is the 49.5𝑚?−50.0𝑚? 50,0𝑚? amount of evaporation. Discussion:

The main goal of this lab was to comprehend the relationship between the salt concentration of a solution and the size of a gummy bear. There were five different solutions that had different amounts of NaCl concentration, and the results of the gummy bear were different in the end. These changes happen through a process called osmosis. It is the movement of water molecules from a solution that has a high concentration of water then molecules go to a solution with a lower concentration of water molecules, through a cell's partially permeable membrane until both sides have the same concentration. The cell in this experiment is the gummy bear. Furthermore, there are three different types of osmosis: hypertonic, Isotonic, and hypotonic. In a hypotonic solution, the low solute concentration and high water concentration are compared inside the cell, which makes water want to come inside the cell. In a hypertonic solution, the outside of the cell is more concentrated than the inside which makes water want to move out of the cell and causes the cell to shrink. Lastly, in an Isotonic solution, the solution concentration is equal on both sides of the membrane and the water moves back and forth trying to establish equilibrium but there is no loss or gain of water. In the hypothesis, “ If the concentration of saline solution is increased then the gummy bear will decrease in mass (g) and the solution’s volume(mL) decrease. This will happen because, in a hypertonic solution, the solution outside the cell is more concentrated than inside and this causes water to leave the cell, and the cell will shrink .” My hypothesis is incorrect as looking at the percentage change in mass and volume this is not true, the only part that is correct is that hypertonic solutions decrease the mass of the gummy bear but by only increasing the concentration of saline solution, it does not become hypertonic. Furthermore, it does not follow this specific pattern since the saline solution was added to solution B but there was an increase in percentage change in mass which

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

shows this hypothesis is wrong. Also in solution “E”10 mL of distilled water, 40 mL of saline solution the percentage change in volume increased instead of decreasing as was mentioned in the hypothesis. The reason the volume increases will be talked about later. Firstly, in “A” solution, no saline solution was added and there was a huge increase in the mass percentage of about 240% and a decrease in volume of about -20% this demonstrates that the distilled water moved into the gummy bear which is hypotonic compared to the gummy bear and the gummy bear was the best out of all the others. Solution B which was 40 mL of distilled water and 10 mL of saline solution is again hypotonic and the percentage change in mass increases and percentage volume change decreases 20% since the water will go inside the gummy bear leaving it with less water in the beaker. Solution C is 30 mL of distilled water, and 20 mL of saline which dissolves some parts of the gummy bear this is very close solution to an isotonic solution since it has a very similar percentage of solute and water concentration the water molecules go back and forth trying to find equilibrium but it is not isotonic because the concentration are not close enough and there was a 78% decrease in the percentage change in mass, and since not fully dissolved it is hypertonic to the gummy bear, and it decreases 4% of the percentage change in volume. One can say since it is hypertonic to the gummy bear the water moves out of the cell causing the solution to have an orange colour. Solution D is 20 mL of distilled water, and 30 mL of saline which fully dissolves this because it is isotonic to the gummy bear and since it is trying to find equilibrium. In an isotonic solution the water goes in both directions and since the gummy bear’s surface layer is different from a cell's cell membrane, it breaks it and slowly dissolves overnight until no more gummy bear parts are left. This explains the 100% decrease in percentage change. Solution E 10 mL of distilled water and 40 mL of saline is hypertonic to the gummy bear since the solution outside the cell is more concentrated than inside, so this makes water move out of the gummy bear and causes it to shrink. In contrast to the controlled gummy bear, the percentage change decreased by 36% which explains why it got smaller than before. Furthermore, the percentage change in volume increases by 3% since water moves out of the cell and this increases the percentage change in volume in a beaker. This can explain the pink colour of the gummy bear after one day. The colour turned bright pink due to the process of osmosis. The Untouched gummy bear F was left out with no change to it and no differences were seen. My prediction for the gummy bears if they stayed for another day is that there would be more percentage change in mass would decrease in all of them since the layer of the gummy bear is not that strong and due to the amount of pressure the water molecules have it would eventually break over time. So, for most gummy bears it would dissolve over 2 days, and in the end, our results would be different. Relevant theory: To take up water from the soil, plants use the osmosis process. Having root hairs that serve as a semipermeable barrier allows water molecules to flow from a high concentration (soil) to a low concentration throughout this process (roots). As a

result, the root hair cells swell and absorb the solvent. The water molecules then travel through tubes (called xylem vessels) to reach the leaves. The process of osmosis makes newer blood cells . When it is put in freshwater, the water travels into the cells travelling, causing the cells to swell. This is due to the fact that ions and other solute particles are more concentrated inside the red blood cell than they are outside. The pressure exerted on the cell's contents by the cell membrane determines how much water can enter the cells. The opposite can also happen when red blood cells are placed in a solution with a higher solute concentration, water moves out of the cell. As a result, cells become smaller The process of osmosis also helps digest food. When you eat or drink something, the food goes down the esophagus, and then into your stomach. Later in your stomach, the food breaks down into even smaller parts that are mixed with stomach liquid. The mixture forms something called chyme. When chyme goes into the small intestine and that is where osmosis takes place. The concentration of intestinal epithelial cells, which make up the lining of the intestines, is lower than that of chyme. Thus, solvent (water) enters these cells through semipermeable membranes in order to reach equilibrium, carrying some nutrients with it. Sources of error: The first source of error was that the electric balance still had the plastic top under it as were measuring the gummy bears that could result in a change in the grams and this could change our mass in grams and could result in a change in percentage change in mass over the five solutions. The second source of error in this experiment can be that when the gummy bears were taken out of the beakers, the amount of the gummy bears was not all collected because they were oozy and some amount could have stayed in the beaker, this source of error could decrease and increase the volume and grams and this causes the percentage change in volume and grams to be different. Another source of error is an instrumental error, this is because we used a graduated cylinder for measuring each amount of NaCl solution, and the person reading the instrument by a person or poorly maintained instruments could cause a change in reading the measurement of each solution and one can say that the accuracy of the measurements decrease and this causes the data to be different. The fourth source of error is an environmental error. When the gummy bear solutions were put in one spot for a whole day. The solutions are sitting in an open container overnight which could cause the solutions to react with the particles in the air since air is not pure and has many different substances this could cause a difference in our solution because it is not a closed container and this could change our numbers and therefore mess up the process of either isotonic/hypotonic/hypertonic solution. The fifth source of error in this lab was that each container had about 0.5 mL of solution evaporated. This was done by only

putting a beaker filled up with water alone overnight with all the other 5 solutions. to see a change and it went from 50 mL to 49.5 mL so 0.5 mL evaporated. This is a source of error since the right amount of volume is not in the experiments and this could cause the data in volume to be less and which could result in different answers in percentage change in volume as well. Conclusion: In conclusion, my hypothesis was “If the concentration of saline solution is increased then the gummy bear will decrease in mass (g) and the solution’s volume(mL) decrease. This will happen because, in a hypertonic solution, the solution outside the cell is more concentrated than inside and this causes water to leave the cell, and the cell will shrink .” It is rejected since the saline solution was increased in the solution “B” but the mass did not increase because it was hypotonic to the gummy bear. One can say that there is no pattern and just increasing only 20% of saline water is not enough to make it hypertonic and decrease its mass and solution’s volume. The hypothesis was written before the experiment and there was a misunderstanding of the concept of osmosis. References: https://www.rankred.com/best-examples-of-osmosis/ https://www.futurelearn.com/info/courses/teaching-biology-inspiring-students-with-plants-in-s cience/0/steps/58750#:~:text=In%20biology%2C%20osmosis%20is%20the,a%20cell's%20p artially%20permeable%20membrane. https://science.umd.edu/classroom/bsci327/Equilibrium.htm

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version