How did ancient astronomers classify stars?
on the basis of their absolute magnitude
on the basis of their apparent magnitude
O on the basis of brightness
on the basis of their distance from Earth

State two physical properties of ionic compound

Calculate the expected ph values of the buffer systems from the experiments (a,b,c,d), using the henderson- hasselbalch equation, ph-pka+log[a-]/[ha]. use for pka values carbonic acid= 6.37, and acetic acid= 4.75.

What is the mass defect of a mole of nuclei with 1.8 x 10^15 j/mol binding energy?