Answer:
I am pretty sure the answer is B. Hope this helps
Explanation:
You'll want to add three amounts of heat.
(1) Specific heat of lowering the temperature from -135°C to the melting point -114°C
(2) Latent heat of fusion/melting
(3) Specific heat of elevating the temperature from -114°C to -50°C
(1) E = mCΔT = (25 g)(0.97 J/g·°C)(1 kJ/1000 J)(-114 - -135) = 0.509 kJ
(2) E = mΔH = (25 g)(5.02 kJ/mol)(1 mol/46.07 g ethanol) = 2.724 kJ
(3) E = mCΔT = (25 g)(2.3 J/g·°C)(1 kJ/1000 J)(-50 - -114) = 3.68 kJ
<em>Summing up all energies, the answer is 6.913 kJ.</em>
We would need 0.037 mol. We know that because of a formula we can use and some data from the problem. The formula would be:
n= Number of heat in kj x 2 moles
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5460 kJ
The number of Kj of heat is provided(100 kJ). The standard enthalpy of combustion is -5460.0 kj. so we multiply 100 kj and 2 moles and then we divide on 5460 kj and the answer is 0.037 moles.
Mesosphere is not one of the compositional layers of earth
The moles of silicon is 4.651 moles
<u><em>calculation</em></u>
The moles of silicon is calculated using Avogadro's constant
that is according to Avogadro's law
1 mole = 6.02 x 10^23 atoms
? moles = 2.80 x 10 ^24 atoms of silicon
by cross multiplication
= [ ( 1 mole x 2.80 x 10^24 atoms) / ( 6.02 x 10 ^23 atoms)]
= 4.651 moles