Respuesta :
Hello there! Your answer is A. 640 J
You can get this by subtracting the temperatures (-136-120= -256.) Then, you divide this answer by 40.0 g to get 6.4.
Answer: a. 640 J
Explanation:
[tex]Q= m\times c\times \Delta T[/tex]
Q= heat gained or released
m= mass of the substance = 40 g
c = heat capacity of solid ethanol= 1.0 J/g ° C
[tex]\Delta T={\text{Change in temperature}}=(-136-(-120)^oC=-16^0C[/tex]
[tex]Q=40g\times 1.0J/g^oC\times -16^oC[/tex]
[tex]Q=-640J[/tex]
Thus heat released when 40.0 g of ethanol cools from −120 °C to −136°C is 640 Joules.
