How many moles are in 20g of potassium (K)?

Explanation:

Hi for this one u just need to remember and use the equation.

then u find mr of potassium which is 39.1.

then u do

you get the answer as 0.5115 write ur answer to 3 significant figures which will be 0.512 moles .

hope this helps :)

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.