Alex has a type of rock called calcite, that sometimes glows. He puts the calcite under a desk lamp but the calcite does not glow. Then he puts it under an ultraviolet lamp and the calcite glows. Why does ultraviolet light make the calcite glow when light from the desk lamp does not? *
1 point

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.

If 22.5 liters of oxygen reacted with excess of hydrogen, how many liters of water vapor could be produced?

Does the number of ions in solution increase, decrease, or remain constant? it continuously decreases. it continuously increases. it decreases at first, then increases. it increases at first, then decreases.