Astandard schedule 40, 2-in. steel pipe (inside diameter 2.067 in., and wall thickness 0.154 in.) carrying steam is insulated with 2 in. of 85% magnesia covered in turn with 2 in. of cork.
estimate the heat loss per hour per foot of pipe if the inner surface of the pipe is at 250°f and the outer surface of the cork is at 90°f. the thermal conductivities (in btu∕hr * ft * °f) of the substances concerned are:
steel, 26.1; 85% magnesia, 0.04; cork, 0.03

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.  

answer; talc and gypsum;

a