Calculate the concentration (m) of sodium ions in a solution made by diluting 50. 0 ml of a 0. 874 m solution of sodium sulfide to a total volume of 250. 0 ml.

Two technicians are discussing how to test a car's exhaust by holding a small piece of paper within an inch of the tailpipe mouth. technician a says that if the paper is vibrating due to a "puffing" output from the tailpipe, this signals a smoothly running engine. technician b says that if the paper is being drawn toward the tailpipe, this could indicate burned exhaust valves. who is correct? a. technician b b. both technicians a and b c. technician a d. neither technicians a or b

Essay questions may also be referred to as a. talk questions c. hard questions b. explain questions d. think questions

A24-n net force acts on a 8-kg rock.what is the acceleration of the rock?