Name two useful materials obtained from fractional distillation of petroleum

Which class of molecules functions as chemical signals? hormones water carbohydrates proteins

Which statement correctly identifies the scientific question and describes why the question is scientific? question 1 refers to the supernatural. question 2 reflects a moral or social value. question 3 refers to something that can be measured. question 4 reflects a question that can’t be observed.

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.)