In bohr's atomic theory when electron moves from one energy level to another energy level closer to the nucleus:

A. Energy is emitted

B. Energy is absorbed

C. No change in energy occurs

D. Light is emitted

E. More than one of these might occur

What is the meaning of Meniscus?

Which statement is true of a catalyst? A. It behaves as a reactant in a chemical reaction. B. It increases the temperature of a reaction. C. It decreases the concentration of the products. D. It accelerates the reaction rates of a mixture.

if 5.00mL of 6.00 M HCI is added to 95.00 mL of pure water, the final volume of the solution is 100.00 mL. What is the pH of the solution?

If you start with 163 g of water at 29◦C, how much heat must you add to convert all the liquid into vapor at 100◦C? Assume no heat is lost to the surroundings. Answer in units of kJ.

What makes an atom an isotope

Assuming that air contains 78 percent N2, 21 percent O2 and 1 percent Ar, all by volume. How many molecules of each type of gas are present in 1.0 L of air at STP?

Two children are playing tag. Child A who is doing the chasing can run 100m in 24 seconds Child B is running away from child A and can run 64m in 21 seconds.

What ion does a base increase

What is the definition of Amplitude?

An excess of NiCO3, 12 g, was added to 40cm cube of sulpheric acid, 2.0 mol/dm cube. The unreacted nickel carbonate was filtered out and the filtrate evaporated to optain the crystals.