Given the following list from the activity series of metals (from most active to least active) k, na, al, mn, cr, cd, co, pb, hg which reaction would you not expect to occur?
1. co²⁺(aq) + al(s) → al³⁺(aq) + co(s) 2. cd(s) + pb²⁺(aq) → pb(s) + cd²⁺(aq) 3. all of the listed reactions will occur. 4. na(s) + mn²⁺(aq) → na⁺(aq) + mn(s) 5. al³⁺(aq) + cr(s) → cr³⁺(aq) + al(s)

In a laboratory experiment, a fermenting aqueous solution of glucose and yeast produces carbon dioxide gas and ethanol. the solution was heated by burning natural gas in a bunsen burner to distill the ethanol that formed in the flask. during the distillation, the ethanol evaporated and then condensed in the receiving flask. the flame of the burner was kept too close to the bottom of the flask and some of the glucose decomposed into a black carbon deposit on the inside of the flask. during this experiment the following changes occurred. which of these changes involved a physical change and not a chemical change? check all that apply. 1-condensation of ethanol 2-evaporation of ethanol 3- formation of carbon dioxide gas from glucose burning of natural gas 4-formation of ethanol from glucose by yeast 5-formation of a carbon deposit inside the flask

Compared with the freezing-point depression of a 0.01 m c6h12o6 solution, the freezing-point depression of a 0.01 m nacl solution is

The bond energy for the van der waals bond between two helium atoms is 7.9×10−4ev. assuming that the average kinetic energy of a helium atom is (3/2)kbt, at what temperature is the average kinetic energy equal to the bond energy between two helium atoms