Q 2.1: There are 92 naturally occurring elements on Earth. How many of these elements are normally found in the human body?

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.

Give a real-world example of an energy transformation that uses two of the following forms of energy: chemical, mechanical, nuclear, gravitational, radiant, electrical, thermal (heat), and/or sound.

In chemistry, the type of an atom (what element it is) is determined by: a) the number of protons it contains in its nucleus. b) the number of neutrons it contains in its nucleus. c) the number of protons it has in a cloud around the nucleus. d) the number of neutrons it has in a cloud around the nucleus. e) the number of electrons it exchanges with its neighbors.