A 0.45g sample of mineral ore is analyzed for chromium and found to contain 0.560mg Cr2O4. Express the concentration of Cr2O3 in sample as a. Percent
b. Parts per thousand
c. Parts per million
d. Parts per billion

In 2002, the rare earth elements mine in mountain pass, california was closed because

For a research project, a student decided to test the effect of the lead(ii) ion (pb2+) on the ability of salmon eggs to hatch. this ion was obtainable from the water‐soluble salt, lead(ii) nitrate, which the student decided to make by the following reaction. pbo(s) + 2 hno3(aq) → pb(no3)2(aq) + h2o losses of product for various reasons were expected, and a yield of 86.0% was expected. in order to have 5.00 g of product at this yield, how many grams of pbo should be reacted? (assume that sufficient nitric acid, hno3, would be used.)

What are several ways to reduce the effect of friction