Which reactions are exothermic?

How many atoms of phosphorus are in 2.50 million of copper (II) phosphate

Why are ionic crystals soluble in water?

A sample of barium nitrate is placed into a jar containing water. The mass of the barium nitrate sample is 27g. Assume the water is at 20 degrees C and the resulting barium nitrate solution is saturated. What mass of water is present in the jar?

A balloon is filled with helium at sea level. The volume was measured to be 3.1 liters at a pressure of 0.97 atm. If the balloon is released, it drifts upward. At a height of 4 kilometers, the pressure is measured to be 0.61 atm.

1. If 22.5 L of nitrogen at 1.25 atm are compressed to 2.10 atm at constant temperature. What is the new volume?

What is limiting reajent?

What elements react the most? Like have the most reactivity.

A neutral atom has an atomic number of 20 and a mass number of 42. How many electrons does the atom have?

A rock is placed into water and the volume of water increase 15ml. what is the density of the rock if it had a mass of 24.3 grams.

Suppose a student did not fully redissolve the Al (OH) 3 that initially formed upon the addition of H2SO4. Predict and explain how this would impact the apparent percent yield this student determines.