Stronitum-90 has a half-life of 29 years. if a site held 2000 kg of this isotope, approximately what mass of strontium-90 would be left after 116 years?

What is the mass of sodium in 3 moles of sodium chloride

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

Why are pipes bursting in the in extremely cold weather?