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 scheme below is from a series of reactions that are part of a synthesis of vitamin a. answer the following questions with reference to this scheme. (i) what is "reagent a"? (ii) draw a step-by-step mechanism which explains the formation of compound c from compound b (iii) which reagents would you use to form compound e from compounds c and d (reagents b and c)? for each reagent suggested above in (ii) explain the role of the reagent in the reaction to (iv) form compound e. you may wish to do this by drawing a mechanism. 1. addition of reagent a но reagent a 2. н,о" thо oh нон-с compound a. compound b. compound c .ch-оh 1. reagent b "сно 2. reagent c сh oh compound e. compound d.

In which situation can a mixture always be called a solution

What happens to isotopes that are unstable?