Why can’t astronomers take a picture of a black hole?

Which of these will change if the air in aclosed bottle is heated? abcdthe mass of the airthe composition of the airthe air pressure in the bottlethe number of air molecules in the bottle

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

13. a covalent bond between two atoms is likely to be polar if: a. one of the atoms is much more electronegative than the other. b. the two atoms are equally electronegative. c. the two atoms are of the same element. d. the bond is part of a tetrahedrally shaped molecule. e. one atom is an anion.