Biology lab/ Chemistry-DUE TODAY IN 5 HRS
Lab 2: The Chemistry of Life
INSTRUCTIONS:
· On your own and without assistance, complete this Lab 2 Answer Form
· Save your Lab2AnswerForm in the following format: LastName_Lab2 (e.g., Smith_Lab2)
Experiment 1: What Household Substances are Acidic or Basic?
Table 1: pH values of common household substances
|
Substance |
pH Guess |
pH Paper |
|
Vinegar |
|
|
|
Sodium bicarbonate solution |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Questions
1. Compare and contrast acids and bases in terms of their H+ ion and OH– ion concentrations.
2. Name two acids and two bases you often use.
Lab 2: Chemistry of Life
Basic properties of the chemistry that underlies biology are explored in this lab. Students will investigate how common household chemicals can influence everyday life.
Time: 1 hour (plus 24 hours preparation time)
Concepts to explore: Atoms, Elements, Compounds, Chemical bonds, Molecules/Macromolecules, Energy and metabolism, Acids and bases, The effects of surface area and volume
Experiments:
Experiment 1: What Household Substances are Acidic or Basic?
• Students use pH paper to test a variety of household substances to determine their acidity. Vinegar and sodium bicarbonate are provided as controls.
Experiment 2: The Effect of Surface Area and Volume
• Students prepare agar blocks stained with an acid indicator, place various size/shape blocks into a beaker of vinegar, and examine the effects of surface area to volume ratios on the diffusion of vinegar into the block.
Experiment 2: The Effect of Surface Area and Volume
Table 2: Results from surface area to volume experiment
|
Cube Dimensions |
Surface Area (cm2) |
Volume (cm3) |
Surface Area : Volume |
Time Require for Complete Color Change |
Distance of Diffusion |
|
1 cm x 1 cm x 1 cm |
|
|
|||
|
1 cm x 2 cm x 2 cm |
|
|
|||
|
1 cm x 1 cm x 6 cm |
|
|
Questions
1. How did the surface area affect the diffusion of the cube? What about the volume? What about the surface area to volume ratio? Which of these had the greatest effect on the diffusion into the cube?
2. How does this experiment demonstrate the need for larger cells to divide?
3. For the three cubes shown below, determine their surface area, volume and surface area to volume ratio. Then, circle the one you believe would be the most efficient and write a summary stating why.
