Elisabeth Haller. 8:20 AM Due Tomorrow
4 points
An experiment is described below.
A student was interested in comparing sunblock lotions, which contain chemicals that protect the skin from sunburn.
The student purchased three different brands of lotion at three different prices and performed an experiment to see
which one best protected the skin. The lotions cost $3, $5, and $7 for an 8-ounce bottle. The sun protection factor
(SPF) was 30 for all three lotions. The student applied equal amounts of each lotion next to each other on one of her
arms. The three areas covered by the lotions were the same size. The student observed the three areas for color
change after two hours of sun exposure
Identify two conditions that were held constant (kept the SAME) in this experiment.
Class comments

Asolution of sodium hydroxide was titrated against a solution of sulfuric acid. how many moles of sodium hydroxide would react with 1 mole of sulfuric acid?

Write the empirical chemical formula of calcium with a mass percent of 38.8, phosphorus with a mass percent of 20.0, and oxygen with a mass percent of 41.3.

Oxidation-reduction reactions (often called "redox" for short) are reactions that involve the transfer of electrons from one species to another. oxidation states, or oxidation numbers, allow chemists to keep track of these electron transfers. in general, one element will lose electrons (oxidation), with the result that it will increase in oxidation number, and another element will gain electrons (reduction), thereby decreasing in oxidation number. the species that is oxidized is called the reducing agent or reductant. the species that is reduced is called the oxidizing agent or oxidant. to sum up: oxidation = increase in oxidation state = loss of electrons = reducing agent reduction = decrease in oxidation state = gain of electrons = oxidizing agent part a which element is oxidized in this reaction? fe2o3+3co→2fe+3co2 enter the elemental symbol. view available hint(s) is oxidized part b which element is reduced in this reaction? 2hcl+2kmno4+3h2c2o4→6co2+2mno2+2kcl+4h2o enter the elemental symbol. view available hint(s) is reduced