All of the elements in Group 2, of the Periodic Table, give away 2 electrons; this results in them having a valence charge of...?

A50.0g sample of liquid water at 0.0 c ends up as ice at -20.0 c. how much energy is involved in this change?

Mary is conducting an experiment on how pollution affects plant growth. how can she ensure that her data are reliable?

Calculate the estimated density of each ball. use the formula d = m/v where d is the density, m is the mass, and v is the volume. record your calculations in table a of your student guide. given that the density of water is 1.0 g/cm3, make a prediction about whether each ball will float in water. record your prediction in table a. what is the estimated density of the table tennis ball? record your answer to the nearest hundredth