Aqueous solutions of lead nitrate and potassium iodide are combined in a test tube. the best proof that a chemical reactions has occurred would be that

What are the percent by mass of copper in penny lab

Schrodinger and heisenberg developed an alternate theory about atomic nature that contradicted some of bohr's model of the atom. how do changes resulting from new technology and evidence affect the reputation of the atomic theory?

In a reaction (at equilibrium) that makes more moles of gas than it consumes, what is the effect of increasing the pressure?