If water's temperature decreases from 90° C to 80°C, what is the sign of entropy of the system and the surroundings? Does increasing a system's temperature decrease the surrounding's temperature?

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 no2 will form when 3.3 moles of cu are reacted with excess hno3?

Which statement justifies that hydrogen peroxide (h2o2) is a polar molecule? the o – h bond is nonpolar and the molecule is asymmetric. the o – h bond is nonpolar and the molecule is symmetric. the o – h bond is polar and the molecule is asymmetric. the o – h bond is polar and the molecule is symmetric.