The macroscopic properties of a pure sample of an unknown solid were examined in order to determine the type of bonding within the particles. The solid is soft and can be cut with a knife. It starts melting at 35 C. It does not dissolve in water - instead it floats on the surface. Make a prediction about of bonding in this compound. Justify your answer.

no, the red giant is the hottest with 2.00.000.000 degrees celsius. while the white dwarf only 25,000 degrees celsius.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.

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.