1st Thermodynamics Law

The 1st law of Thermodynamics

• Energy can not be created or destroyed. It just changes forms.

• Energy can only be created by the sun

• Some energy is lost to the environment.

1200 J of heat are added to a sample of gas while 400 J of work is done by the gas. What is the change in internal energy of the gas?

• 800 J

• 1600 J

• -800 J

• -1600 J

500 J of energy is applied to a gas, if 200J of work is done by the gas. What is the change of internal energy in calories?

• 300cal

• 71.7cal

• 700cal

• 167.4cal

The internal energy of a system decreases by 40cal. What work is done by the gas, if the system absorbs 150J of heat?

• 317.2J

• 17.2J

• 190J

• 110J

The internal energy of a system increases by 50cal while 350J of work is done by a gas. Determine the change in heat .

• 559J

• 400J

• 141J

• 300J

if 600J of heat is needed to increase the internal energy from 15cal to 45cal. What work will the system produce?

• 474.6J

• 570J

• 535.4J

• 630J

40J of work is done by a gas when the system has an increase in internal energy of 125J. What energy is needed to do so?

• 165J

• 85J

• Can´t be possible

• 165Cal

The first law of thermodynamics states that energy is

• created
• destroyed
• conserved
• created and destroyed

What is absolute zero?

• 0 K
• 273 K
• 0^oC

Heat is _____ if heat is removed from a system

• Positive

• Negative

• Neutral