Answer:
Radiation
Explanation:
A sun transfers energy by radiation. However, there are three different modes of heat energy transfer -
a) Radiation
b) Conduction
c) Convection
Since sun is a at a very far distance from earth, it cannot transfer its heat energy by conduction as for this mode of heat transfer two bodies need to be in touch with each other.
For convection mode of heat transfer a medium is required but for transfer of sun's energy (which is electromagnetic radiation) no medium is required.
Hence, Sun will transfer energy by radiation only.
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Answer:
43.05 moles of Al needed to react with 28.7 moles of FeO.
Explanation:
Given data:
Moles of FeO = 28.7 mol
Moles of Al needed to react with FeO = ?
Solution:
Chemical equation:
2Al + 3FeO → 3Fe + Al₂O₃
Now we will compare the moles of Al with FeO.
FeO : Al
2 : 3
28.7 : 3/2×28.7 = 43.05 mol
Thus 43.05 moles of Al needed to react with 28.7 moles of FeO.
The reaction between Na2S and CuSO4 will give us the balanced chemical reaction of,
Na2S + CUSO4 --> Na2SO4 + CuS
This means that for every 78g of Na2S, there needs to be 159.6 g of CuSO4. The ratio is equal to 0.4887 of Na2S: 1 of CuSO4. Thus, for every 12.1g of CuSO4, we need only 5.91 g of Na2S. Thus, there is an excess of 9.58 g of Na2S. The answer is letter C.