Potassium has three naturally occurring isotopes. According to one source of data, Potassium-39 (mass 38.9637 AMU) makes up 93.26%, potassium-40 (mass 39.9640 AMU) makes up just 0.01%, and potassium-41 (mass 40.9618 AMU) makes up 6.73%. What is the average atomic mass of potassium based on these relative abundances? Show all your work for credit, and express your final answer to 2 decimal places, and include the unit.

Spontaneity tell us the direction of the reaction, but not how fast it goes. gibbs free energy brings together enthalpy, entropy and temperature in one easy formula. g = h - ts. and, finally the sign of delta g is always negative for a spontaneous reaction.

Where is the graph ?

Vander waals forces are inter molecular bonds that exist within molecules of the same substance. a water molecule is made up of oxygen and hydrogen atoms which share electrons between each other. the vander waals forces are forces that exist between multitude of different  molecules of water. dipole dipole forces is the type of vander waals force that exist in water. the oxygen atom which is more electronegative pulls the shared electron closer to itself thus generating a partial negative charge while the hydrogen acquire a partial positive charge. these two different charges causes attraction to occur in water molecules.