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
Silicon must have 4 single covalent bond, every single bond has 2 electrons (one pair), so 4·2=8 electrons (octet).
This is a problem involving heat transfer through radiation. The solution to this problem would be to use the formula for heat flux.
ΔQ/Δt = (1000 W/m²)∈Acosθ
A is the total surface area:
A = (1 m²) + 4(1.8 cm)(1m/100 cm)(√(1 m²))
A = 1.072 m²
ΔQ is the heat of melting ice.
ΔQ = mΔHfus
Let's find its mass knowing that the density of ice is 916.7 kg/m³.
ΔQ = (916.7 kg/m³)(1 m²)(1.8 cm)(1m/100 cm)(<span>333,550 J/kg)
</span>ΔQ = 5,503,780 J
5,503,780 J/Δt = (1000 W/m²)(0.05)(1.072 m²)(cos 33°)
<em>Δt = 122,434.691 s or 34 hours</em>
Answer:
is an explanation of an aspect of the natural world that can be repeatedly tested and verified in accordance with the scientific method, using accepted protocols of observation, measurement, and evaluation of results
