Given reactions:
(A) 6CO2(g) + 6H2O(l) + sunlight → C6H12O6(aq) + 6O2(g)
(B) 2H2(g) + O2(g) → 2H2O(g) + energy
Exothermic reactions are those which proceed with the release of heat/energy. In contrast, endothermic reactions proceed with the absorption of energy in the form of heat or light.
Since reaction A required sunlight, it is endothermic. Reaction B releases energy, hence exothermic
Ans: (B)
A is endothermic
B is exothermic
Answer:
The number of atoms in the gemstones of that tiara is
.
Explanation:
Number of diamonds ion tiara = 888
Mass of each diamond = 1.0 carat = 0.200 g (given)
Mass of 888 diamonds in tiara:

Given that diamond is a form of carbon.
Atomic mass of carbon atom = 12 g/mol
Moles of 77.600 g of carbon =
Number of atoms of carbon 14.800 moles:

The number of atoms in the gemstones of that tiara is
.