During chemical reactions, elements come together to form different compounds. Which of the following is true of van der Waals forces?
1. They are repulsive forces between covalent bonds
2. It is a force between molecules that may be repulsive or attractive.
3. They are attractive forces between ionic bonds.
4. It is a force that causes the sharing of electrons between atoms.

Calculate the mass of silver needed to react with chlorine to produce 126g if silver chloride?

Compare and contrast the bohr model and the electron cloud models of the atom.

For a research project, a student decided to test the effect of the lead(ii) ion (pb2+) on the ability of salmon eggs to hatch. this ion was obtainable from the water‐soluble salt, lead(ii) nitrate, which the student decided to make by the following reaction. pbo(s) + 2 hno3(aq) → pb(no3)2(aq) + h2o losses of product for various reasons were expected, and a yield of 86.0% was expected. in order to have 5.00 g of product at this yield, how many grams of pbo should be reacted? (assume that sufficient nitric acid, hno3, would be used.)