Week 2: Chemistry
All of your Bio 10 lab exercises will be done at home on your own time – sometimes fully online; sometimes using materials or specimens you have access to in real life. If you are having difficulty with any part of an exercise, please let me know so I can help you or figure out a substitute activity. Lab worksheets are due on Canvas on Tuesday at 12:30 PM the week after they are introduced (e.g., this Week 2 lab is due on Tuesday 9/1 at 12:30 PM).
Part 1: The Periodic Table
Fill out the chart below using this interactive periodic table: https://www.ptable.com/
Number of protons
Average number of neutrons
Using the interactive periodic table: https://www.ptable.com/), list two elements that you hadn’t heard of before (or had barely heard of before). Are either of them essential to life?
This time, using your data from Q1, find the difference in electronegativity when carbon and hydrogen are covalently bonded to the other atoms. Less than 0.4 and the bond is nonpolar. Between 0.4 and 1.7 the bond is polar.
Difference in electronegativity
Polar or nonpolar bond?
Carbon – Hydrogen
Carbon – Oxygen
Carbon – Nitrogen
Carbon – Phosphorus
Carbon – Sulfur
Hydrogen – Oxygen
Hydrogen – Nitrogen
Part 2: Solutes and solutions
For this, you’ll need four cups (at least 8 oz each), tap water, a microwave, a 1-cup measuring cup, salt, sugar, a teaspoon, and a stopwatch. 1 cup = 8 fluid oz. 1 tsp = 4.9 mL.
Microwave 16 fl. oz. (2 cups) of water until it is boiling, then divide it into 2 teacups (8 fl. oz. each). Take 16 fl. oz. of cold water, and fill the other 2 teacups with 8 fl. oz of cold water each. It is OK if the cups are bigger than 8 fl. oz. and therefore are not completely full.
One at a time, for each hot and cold pair of teacups, dissolve 1 tsp of either white table sugar (sucrose) or salt (sodium chloride) in each cup. Gently stir with a spoon and use a stopwatch to time the process. The solute is dissolved when you can no longer see any grains swirling, nor crunch them with a spoon on the bottom of the cup. Report your results below.
Hot water, 1 tsp sugar: How long to dissolve?
Cold water, 1 tsp sugar: How long to dissolve?
Hot water, 1 tsp salt: How long to dissolve?
Cold water, 1 tsp salt: How long to dissolve?
Interpret your results below! Which of these substances was an ionic solid: salt, sugar, or neither? Which was a polar molecule: salt, sugar (sucrose), or neither? Did the temperature of the water affect the rate at which the substance dissolved, and if so, how and why?