Which describes how the sodium ion is formed?

a.
sodium loses an electron to become a positive ion.

b.
sodium loses a proton to become a negative ion.

c.
sodium gains an electron to become a positive ion.

d.
sodium gains a proton to become a positive ion.

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.