Hydrogen is a pure substance represented by the chemical symbol h. which of the following best describes hydrogen?

a-hydrogen is a compound made of two or more kinds of atoms.
b-hydrogen is an element made of only one kind of atom.
c-hydrogen is a compound made of only one kind of atom.
d-hydrogen is an element made of two or more kinds of atoms.

What is a carrier wave and how does it affect what you hear on the radio

Aboy with a mass 25 kg climbs into a small tree. he sits on a branch that is 2.o m above to the ground.what is his gravitational potential energy above the ground?

4r-134a enters the condenser of a residential heat pump at 800 kpa and 50°c at a rate of 0.022 kg/s and leaves at 750 kpa subcooled by 3°c. the refrigerant enters the compressor at 200 kpa superheated by 4°c determine (a) the isentropic efficiency of the compressor, (b) the rate of heat supplied to the heated room, and (c) the cop of the heat pump. also, determine (d) the cop and rate of heat supplied to the heated room if this heat pump operated on the ideal vapor-compression cycle between the pressure limits of 200 and 800 kpa. (0.757, 4.37 kw, 5.12, 6.18, 3.91 kw)