A45-g aluminum spoon (specific heat 0.88 j/g °c) at 24 °c is placed in 180 ml (180 g) of coffee at 85 °c andthe temperature of the two become equal.(a) what is the final temperature when the two become equal? assume that coffee has the same specific heat aswater.

When Heat lost by coffee -q= m( coffee) * C (coffee) * ΔT

and Heat gained by spoon q = m (spoon) * C (spoon) * ΔT

when q = -q 
∴ m(coff)* C(coff) * ΔT (coff) = m(sp)* C(sp)*ΔT(sp)
when the final tempreature of both will be the same so,
m(coff) * C(coff) * ( Tf - Ti(coff)) = m(sp) * C(sp) * (Tf- Ti(sp)

by substitution:
note: as the coffe will reduce heat so, ΔT = (85-Tf)
and the spoon will gain heat so ΔT = (Tf-24)
180 g * 4.186 * (85-Tf) = 45 * 0.88 * (Tf- 24)
∴Tf = 81 °C 

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.