If a system has 425 kcal of work done to it, and releases 5.00 × 102 kj of heat into its surroundings, what is the change in internal energy of the system?

The change in the internal energy of the system is .

Further explanation:

Thermodynamics:

The branch of chemistry that deals with heat, temperature and its connection with work is known as thermodynamics. It has wide uses in pyrometallurgy, gas-phase reaction gas-solid reaction, and ATP generation.

First law of Thermodynamics:

It is based on the law of energy conservation that states total energy of system to be constant. According to this law, internal energy change is determined by sum of work done on the system and heat supplied. Its mathematical expression is as follows:

      …… (1)                                                            

Here,

is the change in internal energy of the system.

q is the heat released by the system.

W is the work done to the system.

The value of W is 425 kcal.

The value of q is .

Substitute these values in equation (1).

Therefore the change in internal energy of the system is -1278200 J.

Learn more:

1. What is the final temperature of copper? link

2. Calculate the specific heat of gold: link

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Thermodynamics

Keywords: internal energy, heat, work, q, W, P, -1278200 J, thermodynamics, first law of thermodynamics, law of conservation of energy, total energy, isolated system, change in internal energy.

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"

the answer is 303.15 or 303