A hand sanitizer was advertised to be more effective at killing bacteria than any antibacterial soap. Students were split evenly into 4 groups to test this claim. Groups 1-3 washed their hands using the assigned hand sanitizer or soap (see table) and warm water for two minutes, and then dried their hands with a paper towel. Group 4 rubbed their hands vigorously for 2 minutes in warm water, without any soap or sanitizer, and then dried their hands with a paper towel. After washing, each student’s hands were swabbed and the swab was applied to a culture plate and incubated. Finally, the bacterial cultures were counted. what is the independent variable?

Group 4

Explanation:

The control group in this case would be those students in group 4.

The control group during an experiment is a group that does not receive the treatment administered to other groups and as such used as a standard for measuring the effects of the treatment on other groups. Whatever differences that exist between the control group and the various treatment groups is attributed to be as a result of the treatment administered to the groups.

In this case, group 4 only used warm water for washing their hands instead of the hand sanitizer/soap used by the other groups. Whatever differences found out in the bacterial count in their respective culture swabs can be attributed to the effects of the hand sanitizer/soap.

hydroxyl -oh

alcohols, always polar, can form hydrogen bonds with h2o molecules

carboxyl -cooh  

cargoxylic acids, has acidic properties which is a source of hydrogen ions, found in cells in ionized for with a charge of oh-1

carbonyl > co

ketone if within skeleton, aldehyde if group is at the end of skeleton, k & a may be structural isomers, it determines 2 sugars (ketose & aldose)

amino -nh2

amines, acts as a base, it can pick up h+ ions from surrounding solution, ionized with charge of 1+

methyl ch2

addition to rna/dna affects and gene expression

phosphate -opo3 ²⁻

organic phosphates, contributes to negative charge to, molecule that it is a part of, and potential to react with h20

sulfhydryl -sh

thiols, cross-linking stabilize the protein, and it is structure