50 points- chemistry
some thermodynamic properties of ethanol are listed in the table.

thermodynamic properties

property value
c (solid) 0.5 j/g °c
c (liquid) 1.0 j/g °c
c (gas) 2.0 j/g °c
melting point −114 °c
boiling point 78 °c

how much heat is released when 50.0 g of ethanol cools from 90 °c to 79 °c?

1,200 j
1,100 j
600 j
550 j

1,100 J.

Explanation:

Q = m.c.ΔT.

where, Q is the amount of heat released from ethanol cooling,

m is the mass of ethanol (m = 50.0 g),

c is the specific heat of ethanol in the gas phase, since the T is cooled above the boiling point (c = 2.0 J/g °C),

ΔT is the temperature difference (final T - initial T) (ΔT = 79.0 °C – 90.0 °C = - 11.0 °C).

∴ Q = m.c.ΔT = (50.0 g)(2.0 J/g °C)(- 11.0 °C) = - 1100 J.

The system releases 1,100 J.

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.