Aradioactive sample contains 1.55 g of an isotope with a halflife of 3.8 days. what mass of the isotope remains after 5.5 days?

Why is the vapor pressure of a warm lake higher than the vapor pressure of a cold lake? o a. warm water has a greater heat of vaporization. ob. warm water evaporates more quickly. cool water evaporates more quickly. od. cool water has a greater heat of vaporization.

Neils bohr believed that electrons orbited the nucleus in different energy levels, based on strong support from

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