A-LEVEL PHYSICS: 11.2.1: the First Law of Thermodynamics (SaveMyExams)

Question 1

the first law of thermodynamics is based of the principle of…

Answer 1

conservation of energy

Question 2

first law of thermodynamics:

Answer 2

ΔU = Q - W

change in internal energy = heat added - work done by system

Question 3

ΔU:

Answer 3

change in internal energy

Question 4

Q:

Answer 4

heat added

Question 5

W:

Answer 5

work done by system

Question 6

open system:

Answer 6

gas can flow in & out of the region

Question 7

closed system:

Answer 7

gas can only remain within the region boundary

Question 8

an ___ system is where gas can flow in and out, whilst in a ___ system, gas can only remain within the boundary

Answer 8

open, closed

Question 9

in both open and closed systems, work can ‘cross’ the ___

Answer 9

boundary

Question 10

amount of heat transfer Q is:

Answer 10

-positive if heat energy is added

-negative is heat energy is removed

Question 11

change in internal energy ΔU is:

Answer 11

-positive if internal energy increases

-negative if internal energy decreases

Question 12

work done W is:

Answer 12

-positive if work is done by the gas (expansion)

-negative if work is done on the gas (compression)