Copper has a hfus = 13.0 kj/mol. what mass of copper releases 112.4 kj of heat as it freezes? 9.42 g 6.75 g 549 g 1590 g

Answer is: mass of copper is 549 g.

Hfus(Cu) = 13.0 kJ/mol; the heat of fusion of copper..

Q = 112.4 kJ; heat released.

Q = n(Cu) · Hfus(Cu).

n(Cu) = Q ÷ Hfus(Cu).

n(Cu) = 112.4 kJ ÷ 13.0 kJ/mol.

n(Cu) = 8.65 mol; amount of copper.

m(Cu) = m(Cu) · M(Cu).

m(Cu) = 8.65 mol · 63.546 g/mol.

m(Cu) = 549.428 g; mass of copper.

while cooking a piece of 1/2 pound beef steak, a cast iron pan (2.4kg in weight) was heated 260 celsius.

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.