2. Phosphorus has an atomic number of 15, atomic mass of 31 and has a charge of -3. How many protons does Phosphorus has

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?

Ariver current has a velocity of 5km/h relative to the shore, and a boat moves in the same direction as the current at 5 km/h relative to the river. how can the velocity of the boat relative to the shore be calculated?

How many moles are in 7.2 x 10^23 carbon molecules?