Which of these elements has an electron configuration of [kr]5s2?
barium

calcium

rubidium

strontium

What is the equilibrium constant of aa+bb=cc+dd

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.

Which of these is an example of pseudoscience? a) predicting the time of sunrise based on data on position of earth b) predicting the date of the moon phases based on data on position of earth c) predicting eclipses based on the position of the sun and the moon d) predicting future events in a person's life based on the position of the moon