Lecture 5 Formulas

Question 1

Specific Heat Capacity of Water

Answer 1

4.18 kJ/(kg x C) or 1 kcal/(kg x C)

Question 2

Human Tissue Heat Capacity

Answer 2

3.5 kJ/(kg x C)

Capacity is approximately 0.85 of water

Question 3

Specific Heat of Blood

Answer 3

0.86 kcal/(kg x C)

Question 4

Heat Capacity of the Body

Answer 4

3.5 kJ/(kg x C) x 70 kg = 245 kJ/C

Question 5

Heat Required

Answer 5

Weight (kg) x Specific Heat x Temp Change (C)
MCT
When warming blood, specific heat is 3.6 kj/(kgxC) which is 4.18 (water) x 0.86 (blood products)

Question 6

Latent heat of water at 100C

Answer 6

2.26 MJ/kg

Takes 2.26MJ of energy to convert 1kg water to 1kg steam at 100C

Question 7

Latent heat of water at 37C

Answer 7

2.42MJ/kg

Takes 2.42 MJ of energy to convert 1kg of water to 1kg of water vapor at 37C

Question 8

SI units of heat capacity

Answer 8

Amount of heat required to raise the temperature of a given object by 1 kelvin
J/K

Question 9

Change in MBT

Answer 9

2L at 4C brings temp down 1C
2L at 21C brings temp down 0.5C
4L at 4C brings temp down 2C
4L at 21C brings temp down1C

Question 10

Heat Loss Warming Gas

Answer 10

Heat loss = Flow x Specific Heat x Temperature Change

Question 11

Specific Heat Air

Answer 11

0. 29 cal/(LxC)

1. 2 J/(LxC)

Question 12

Temperature Measurement Methods

Answer 12

Conductivity Change = Thermistor
Resistivity Change = Heated Wire
Volume Expansion = Bimetallic Strip, Mercury/alcohol thermometer
Emissivity =  IR detector, Thermocouple
Index of Refraction = Liquid Crystals