What is the mass of 2.23 × 10^23 atoms of aluminum?

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

Why is the bond angle in a water molecule less than the bond angle of methane? a. the central oxygen atom in water has two lone pairs of electrons, whereas the central carbon atom in methane has no lone pairs. b. the central hydrogen atom in water has one lone pair of electrons, whereas the central carbon atom in methane has two lone pairs. c. the central oxygen atom in water has four lone pairs of electrons, whereas the central carbon atom in methane has only one lone pair. d. the central oxygen atom exerts more repulsive force on surrounding atoms than the central carbon atom in methane does. reset next

Drug abuse will not lead to physical and psychological dependence. true or false ?