Calcium oxide, CaO, reacts with carbon in the form of graphite. Calcium carbide, CaC2, and carbon monoxide, CO, are produced in an endothermic reaction. CaO(s) + 3C(s) + 462.3 kJ → CaC2(s) + CO(g)

If 1.38 × 1024 molecules of calcium oxide react with excess graphite. How much energy is needed?

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

i don't see a text, but i am gonna assume this *orbit* the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.

b.

the accuracy of the data.