How many moles of ions are in 2.90 mol of K2SO4

The atoms of a solid aluminum can are close together, vibrating in a rigid structure. if the can is warmed up on a hot plate, what happens to the atoms?

How many moles of oxygen gas are produced from the decomposition of six moles of potassium chlorate

Structure of the atoms: discovery of the nucleus in 1909i need answering all of these questions