Particulate Nature of Matter 1: Temperature & Heat, Intro into Uncertainty, Temperature Scales

Question 1

When can we say that thermal equilibrium has been reached?

Answer 1

When there is no net transfer of heat between 2 touching objects (due to the 2 objects both having the same temperature).

Question 2

What is heat?

Answer 2

The total internal kinetic energy of all the particles of in object AND a form of energy which flows as a result of temperature difference.

Question 3

What is internal energy?

Answer 3

The total kinetic & potential energy of particles in an object. It is randomly distributed throughout the particles of an object.

Question 4

What is the resolution of measuring instruments?

Answer 4

The smallest increment.

Question 5

What is the absolute uncertainty of measuring instruments in relation to resolution?

Answer 5

+/- resolution/2

Question 6

What is standard atmospheric pressure?

Answer 6

100kPa

Question 7

What is the triple point of pure water?

Answer 7

0.61kPa & 0.01 degrees Celsius

Question 8

How is the absolute scale of temperature determined?

Answer 8

It is determined relative to two fixed points: absolute zero and the triple point of water.

Question 9

How is the Celsius scale determined?

Answer 9

It is determined relative to two fixed points: the freezing and boiling points of water (defined as 0 and 100 degrees Celsius respectively) at standard atmospheric pressure. (A lower atmospheric pressure would mean there’s not much holding the particles together, and therefore the melting and boiling points would be lower.)

Question 10

What is 0K in degrees Celsius?

Answer 10

0K = -273.15 degrees Celsius

Question 11

What temperature scale is considered a SI base unit?

Answer 11

Kelvin

Question 12

Can you define temperature?

Answer 12

The average kinetic energy of all the particles in an object AND a property of a body which determines the direction of heat transfer.

Question 13

When do the units go after the uncertainty?

Answer 13

When there is absolute uncertainty.

Question 14

When do the units go before the uncertainty?

Answer 14

When there is fractional/percentage uncertainty.

Question 15

What is the formula for converting from Kelvin to degrees Celsius?

Answer 15

T(K) = θ(°C) + 273 OR θ(°C) = T(K) - 273

Question 16

How are the Celsius and absolute scales related?

Answer 16

An increase in temperature by 1K is the same as an increase in temperature by 1 degrees Celsius.

Question 17

Why do dust particles move with a constant random jiggling movement?

Answer 17

The smaller molecules in the surrounding fluid constantly hit the dust particles. When they do this, they transfer momentum to the dust particle. This causes its direction and speed (velocity) to change.

Question 18

Describe the internal energies of gases, relative to the other states of matter.

Answer 18

Maximum internal KE and maximum PE. Maximum internal PE is equal to 0.

Question 19

Describe the internal energies of liquids, relative to the other states of matter.

Answer 19

Less internal KE than a gas but more internal KE than a solid. Internal PE is negative but not as negative as a solid.

Question 20

What does potential energy denote?

Answer 20

It denotes how much energy is needed to get the particles of an object to 0 J of PE - usually the PE at which the particles are completely separate. PE is measured with negative numbers.

Question 21

Describe the internal energies of solids, relative to other states of matter.

Answer 21

Lower internal KE than liquid and gas; very negative internal PE.

Question 22

Describe the internal energies of matter at absolute zero, relative to other states of matter.

Answer 22

KE is almost zero, and therefore the PE is at its lowest.

Question 23

How can we tell that particles in a solid have potential energy?

Answer 23

They are held in fixed positions due to electrostatic attraction between the particles.

Question 24

What is the difference between nuclear fission and nuclear decay?

Answer 24

Nuclear fission is when a large, unstable nucleus splits into two daughter nuclei and some neutrons (usually after a neutron is shot into it).

Nuclear decay is when an unstable nucleus undergoes alpha, beta, gamma, or neutron decay.