The air in an inflated balloon (defined as the system) is warmed over a toaster and absorbs 130 j of heat. as it expands, it does 78 kj of work. what is the change in internal energy for the system?

-77870 J is the change in internal energy for the system.

Explanation:

According to the first law of thermodynamics:-

Where,  

U is the internal energy

q is the heat

w is the work done

From the question,

q = + 130 J  (+ sign as the heat is being absorbed)

(negative sign as work is done by the system)

So,

-77870 J is the change in internal energy for the system.

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.