3(NH4)2CO3 what does the 3 in front mean?​

An air-standard stirling cycle operates with a maximum pressure of 600 psia and a minimum pressure of 10 psia. the maximum volume of the air is 10 times the minimum volume. the temperature during the heat rejection process is 100°f. calculate the specific heat added to and rejected by this cycle, as well as the net specific work produced by the cycle. use constant specific heats at room temperature. the properties of air at room temperature are r

Which is not a source of noise pollution? a)airplanes b)acid rain c)machines d)cars

How does the amount of energy required to hold each proton and neutron in the nucleus compare to the energy released when they are removed?