Sarah goes to the beach to conduct an experiment. Her testable question is: “What effect does the time of day have on the temperature of water 10 ft below the surface?” which condition should be kept as constants (controlled variables) in her experiment? -weather
-time of day
-where she collects the water
-the clothes and shoes she wears
-if there is a crab nearby
-Temperature of the water
-Type of thermometer she uses
-What she collects the water in
-Amount of water collected

(Multiple Choice question)

1. suppose a reaction mixture, when diluted with water, afforded 300 ml of an aqueous solution of 30 g of the reaction product malononitrile [ch2(cn)2], which is to be isolated by extraction with ether. the solubility of malononitrile in ether at room temperature is 20.0 g/100 ml, and in water is 13.3 g/100 ml. what weight of malononitrile would be recovered by extraction with (a) three 100-ml portions of ether and (b) one 300-ml portion of ether? suggestion: for each extraction, let x equal the weight extracted into the ether layer. in part (a), the concentration in the ether layer is x/100 and in the water layer is (30 x)/300; the ratio of these quantities is equal to k 20/13.3.

How many moles of carbon dioxide will form if 2.5 moles of c3h8 is burned

There is one girl i like and i don't know how to tell her that, i have a feeling she knows but if she doesn't i don't want to make a fool out of myself how is one way to boost my confidence on asking her out