-. A student is investigating the volume of hydrogen gas produced when various metals react with hydrochloric acid. The student uses an electronic balance to
determine that the mass of a sample of zinc metal is 16.35 g. How many moles
of zinc are in this sample?

Identifying limitations of kinetic-molecular theorya chemist is studying the properties of a gas under various conditions. he observes that when the gas is at room temperature and low pressure, it behaves as an ideal gas. when the gas is cooled to 10 kelvin and is placed under high pressure, however, it deviates significantly from an ideal .

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 a solution had a ph of 7 what is the solution