The convex lens of a magnifying glass is used to focus sunlight, as shown. Which of the lettered parts of the lens diagram represents the focal point?
Part A - the imaginary vertical line that divides the lens in half
Part B - the point at which the light converges on the other side of the lens
Part C - the distance between the optical center and where light converges
Part D - the point in the center of the lens

What is avogadro’s number, and why is it useful

You have a sample of a gas that occupies a volume of 17ml at -111 degrees celsius. what volume does the sample occupy at 88 degrees celsius? show all work asap

A3.37-mg sample of protein was chemically digested to convert its nitrogen into ammonia and then diluted to 100.0 ml. then 10.0 ml of this solution was placed in a 50-ml volumetric flask and treated with 5 ml of phenol solution plus 2 ml of sodium hypochlorite solution. the sample was diluted to 50.0 ml, and the absorbance at 625 nm was measured in a 1.00-cm cuvette and found to be 0.486. for reference, a standard solution was prepared from 10.0 mg of nh4cl (molar mass = 53.49 grams/mole) dissolved in 1.00 l of water. then 10.0 ml of this standard was placed in a 50-ml volumetric flask, treated in the same manner as the unknown, and the absorbance found to be 0.323. finally, a reagent blank was prepared using distilled water in place of unknown, it was treated in the same manner as the unknown, and the absorbance found to be 0.076. calculate the weight percent of nitrogen in the protein.