When utilizing a transmission electron microscope, why is it necessary to stain the specimen with heavy metal salts?

A32 year old immigrant from a patriarchal country is giving birth. as she is delivering the baby, she tearfully confesses to her doctor that this is her 4th child and she simply cannot handle any more children. she tells the doctor that her husband refuses to use contraception or allow her to, and she begs her doctor to tie her tubes and not tell her husband. the doctor complies. was hipaa violated? why or why not?

Which type of bond is present in hydrogen sulfide (h2s)? the table of electronegativities is given. a. hydrogen b. ionic c. nonpolar covalent d. polar covalent

How many moles of lead are in 1.50 x 10^12 atoms of lead? could you explain the answer as well and not just give it to me i am refreshing for finals and i need to know how to do it