November 25, 2014

Posts by Chemistry

Total # Posts: 205

A certain mine produces 2.5 108 kg of copper from chalcopyrite (CuFeS2) each year. The ore contains only 0.80% Cu by mass. (a) If the density of the ore is 2.0 g/cm3, calculate the volume of ore removed each year. (b) Calculate the mass of SO2 produced by roasting (assume ...
April 13, 2007

I asked this question yesterday and it was answered, but I still have a question on it. Standard entropies for substances are defined at a pressure of exactly 1 bar in some books or exactly 1 atm(760 torr) in different books. For gases, this correction factor would be..... in ...
April 4, 2007

I need some help with calculating percent yield and percent purity of aspirin. Here's my data (questions follow): SYNTHESIS Mass of salicylic acid.., 2.0 g Volume of acetic anhydride.., 5 mL Mass of watch glass.., 22.10 g Mass of aspirin and watch glass.., 28.01 g Mass of ...
March 24, 2007

Which of the following does form a Group II cation? lead iron cobalt nickel How do you figure this one out? You must know what is in group II. Fe, Co, and Ni are in group III. Pb is in both group I and group II. Pb ppts as the chloride in group I and as the sulfide in group II.
February 20, 2007

Al3+ and Pb2+ act as acids or bases in acidic or alkaline environment. True or False? I think this is true because they are amphoteric, but I am not sure. yes. They are amphoteric.
February 20, 2007

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