I need an explanation for this Biology question to help me study.
Complete the lab and fill out the document attched with the question.
- select baby powder, baking soda, corn starch, powdered sugar, and zinc oxide. Set the other samples aside for later use.
Note: Zinc oxide is a common ingredient in some sunscreens, diaper ointments and makeup.
- Review Data Table 2–6 which list a series of tests that will be applied later in the experiment to identify unknown substances.
Test for Appearance:
- With scissors and a ruler, cut a 10 x 10 cm piece of paper. Label the paper “baby powder.”
- Open the vial containing baby powder. Transfer all of the contents of the vial to the labeled piece of paper.
- Describe the appearance of the baby powder and record your observations in Data Table 2.
Note: Close visual observation may offer subtle differences among the samples.
- Repeat steps 4–6 for each of the substances in the remaining 4 vials (baking soda, corn starch, powdered sugar, and zinc oxide). Be sure to label each piece of paper appropriately.
Test for Scent:
- Test the scent of the baby powder by using your hand to gently waft the odors toward your nose. Record observed scent in Data Table 3.
Note: Do not directly inhale any of the substances. Waft the odors toward your nose using a circular motion with your hand at a distance of 6-8 inches.
- Repeat step 8 for the four remaining substances.
Test for Mass (g):
- Locate a digital scale. Turn on the scale, and set the scale to grams.
- Using scissors cut a piece of paper that is about 5 x 5 cm2, just big enough to cover the scale. This will be your weigh paper.
- Using scissors cut a piece of paper that is about 10 x 10 cm and label it Baby Powder. This will be the paper you use to pour out the baby powder onto.
- Place the piece of paper on the scale. Notice that the mass of the paper in grams is displayed.
- Press the power button once to tare the scale to read 0.00 g.
Note: The scale will read 0.00 g with the piece of paper on top. The scale is set to automatically turn off after some time. If this occurs, simply press the power button to turn the scale back on. The scale will again read zero.
- Locate a kitchen knife and a ¼-teaspoon.
- Pour the contents of the vial that contains the baby powder onto the 10 x 10 cm2.
- Use the knife and measuring spoon to collect a heaping spoonful of baby powder from the 10 x 10 cm paper.
- Scrape the excess powder from the spoon and back onto the paper labeled baby powder. The sample of baby powder should be perfectly even with the top of the spoon, as shown in Figure 2.
- Reserve the excess baby powder for future steps.
- Ensure that the scale is still on, and gently transfer the baby powder from the measuring spoon to the center of the paper on the scale. Be careful not to spill any powder, as this would result in experimental error. Gently tap the spoon on the paper so that all of the contents are transferred.
- Record the mass of the baby powder in grams in Data Table 4.
- Locate a test tube and a marking pen. Label the test tube BP. It will contain the ¼ tsp baby powder and be used in later steps.
- Gently fold together two opposite corners of the weigh paper containing baby powder. Use the paper as a funnel to slowly and carefully add the baby powder to the test tube. See Figure 3.
- Locate a 24 well plate in your kit. Set the well plate on a solid surface and place the test tube in the well plate.
- Dispose of the weigh paper in a trash bin, as it may hold some residual powder and thus cannot be reused for the other substances.
- Rinse the measuring spoon and knife with copious amounts of tap water and dry thoroughly with a paper towel.
- Repeat steps 10–26 for the four remaining substances. Be sure to create new 5 x 5 cm2 weigh paper and 10 x 10 cm2 paper, and properly clean the equipment between testing each sample.
Test for Behavior in Water:
- Gather a 1-teaspoon and the funnel provided in the kit.
- Securely hold the funnel and test tube containing the substance in one hand. The funnel opening should rest just at the lip of the test tube, as shown in Figure 4.
- While still holding the test tube and funnel, fill the 1-teaspoon to the brim with tap water.
- Add the water to the funnel and allow it to move into the test tube.
- Add a second teaspoon of tap water.
- Set the funnel and the measuring spoon aside.
- Place a gloved thumb over the opening of the test tube and vigorously shake the test tube to completely mix the solid with the water.
- Place the test tube back in the well plate and allow the solution to sit for 1 minute.
- Record observations for the behavior of baby powder in the presence of water in Data Table 5.
Note: Be as specific as possible with your observations. Particles may dissolve, become suspended, precipitate (settle to the bottom of the test tube), or display a combination of behaviors.
- Rinse the measuring spoon with copious amounts of tap water and dry well with paper towels.
- Repeat steps 29–37 for the four remaining substances.
Test for Behavior in Vinegar:
- Locate the bottle of vinegar and remove the cap. Add 10 drops of vinegar to a clean well in the 24 well plate.
- Use a toothpick to scoop up a small amount of baby powder, as shown in Figure 5.
- Add the baby powder to the well containing the vinegar and observe immediately.
- Record observations for the behavior of baby powder in the presence of vinegar in Data Table 6.
- Repeat steps 40–42 for the four remaining substances.