What is the first step when calculating the molar mass of a compound ? a. multiply the total number of atoms in the compound by the compound by the combined molar mass. b.add the total number of atoms for each element of the compound together. c.add the molar mass for each element of the compound together to find the total. d.multiply the number of atoms for each element in the compound by the molar mass.

Which of the following pairs of elements belong to the same groupa. h and he b. li and bec. c and pb d. ga and ge

Some liquids can be distilled, but only at temperatures that are so high that it is impractical, or so high the compound decomposes. explain why distillation such compounds at significantly less than atmospheric pressure (some degree of vacuum) would solve this problem.

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.)