Cho biết các năng lượng liên kết sau đây: EC-C = 343,4 kJ/mol, EC=C = 597,7 kJ/mol; EC-H = 418,4 kJ/ mol
a) Hãy tính năng lượng nguyên tử hóa của benzen ứng với công thức cổ điển của Kekule
b) B) So sánh với giá trị thực nghiệm EA = 5496,7 kJ/mol và giải thích

2points why do scientists need governmental funding? o a. government politicians ask all the important scientific questions. o b. scientists have to pay taxes to the government on the money they make. o c. the cost of doing scientific research can be very high. o d. the government is controlled by scientists. submit

Straightforward questions answered in the powerpoint slidesreaction: heating the starting materials under refluxwhat does it mean to heat under reflux? why do we choose water as the reflux solvent? what are boiling chips used for? why do we put a condenser on top of the reaction? why do we add heat and let the reaction stir for 30 minutes? why do we add sulfuric acid to the reaction after it cools as opposed to when it’s still hot? separation: filtration of precipitatewhy don’t we do an aqueous and organic extraction in the separatory funnel? why do you rinse the salicylic acid on the filter with ice cold water? purification: recrystallization of salicylic acid (no hot filtration needed)what is the difference in the amount of room temperature water vs. boiling water needed to dissolve the salicylic acid (assume a 1.2 gram yield of salicylic acid)? remember, in the lab if you need x ml of boiling water to dissolve a solid, then you should add a little more (definitely no more than 1.5 times the theoretical amount) to ensure it doesn’t recrystallize prematurely. analysis: melting point of salicylic acidwhat can you conclude if the melting point of the salicylic acid you just synthesized is 152-155oc and the 1: 1 mix of your product and “synthetic” salicylic acid is 151-154oc?

What is the molar mass of potassium nitrate, kno3