A10 cm thick brick wall is initially at a uniform temperature of 240 °c. at time t = 0, both the surface of the wall are subjected to convective cooling into an ambient at temperature 40 °c with a heat transfer coefficient of 60 w/m2 .k. the following physical properties of the brick are available: k = 0.69 w/m. k; ρ = 2300 kg/m3 and cp = 0.6 j/g. k i. determine the time require to reach the midplane temperature 64 °c. ii. after 2 hours what will be the temperature of the plane 1 cm from the outer surfaces.

the answer is definitely c.

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.

in chemistry, adhesion and cohesion are attractive forces that exist between molecules. they hold the molecules together from each other. they are different in that adhesive force exists between molecules of different substance while cohesive force happens between molecules of same substance.

adhesion between water and glass causes water molecules at the edge of water and glass interface to climb up the wall in a narrow glass tube. this is called capillary action. cohesion is what gives glass its shape and causes water to form a droplet.