Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT...

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Temperature Definition Instrument Scales

Transcript of Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT...

Page 1: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

• Temperature • Definition• Instrument• Scales

Page 2: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

TEMPERATURE

• Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!!

• ( Heat is)

• Review: What is KINETIC ENERGY?

Page 3: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

KINETIC ENERGY (KE)

• Is associated with movement. • If an object is moving fast has high KE• If an object is moving slowly it has low KE

Page 4: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Temperature• In scientific

measurements, the Celsius and Kelvin scales are most often used.

• The Celsius scale is based on the properties of water.□ 0C is the freezing point of

water.□ 100C is the boiling point

of water.

Page 5: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Temperature:

A measure of the average kinetic energy of the particles in a sample.

If an object is at HIGH temperature its particles are moving FAST

At LOW temperature particles move SLOWLY

Page 6: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Instrument to measure temperature

THERMOMETER

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FIXED POINTS OF A THERMOMETER

• BOILING POINT OF WATER

• FREEZING POINT OF WATER

Page 8: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Temperature

• The Kelvin is the SI unit of temperature.

• It is based on the properties of gases.

• There are no negative Kelvin temperatures.

• K = C + 273.15

Page 9: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Temperature

• The Fahrenheit scale is not used in scientific measurements.

• F = 9/5(C) + 32• C = 5/9(F − 32)

Page 10: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

2. SI unit for temp. is the Kelvin

a. K = C + 273 (10C = 283K)

b. C = K – 273 (10K = -263C)

Page 11: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

DO NOW

1. What is 35ºC in Kelvin?

2. What is 10 K in ºC?

Page 12: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

What is the temperature of the beakers?

• Which one needs more heat to boil?

• What is the difference between heat and temperature?

Page 13: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

• What is the relationship between heat and temperature?

Page 14: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

1. Temperature is the average kinetic energy of the particles in a substance.

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Heat and Temperature

• The temperature of an object tells us how HOT the object is. It is measured in degrees Celsius - °C, with a thermometer.

• Temperature is NOT a form of energy.• HEAT IS A FORM OF ENERGY!!!

Page 16: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

So how temperature and heat are related?

• Temperature is NOT the same as HEAT ENERGY although the two quantities are related.

Page 17: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

They are both a the same temperature. Which contains more

heat?

Page 18: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

• Types of energy

• POTENTIAL ENERGY :

STORED ENERGY. The energy inside the substance.

• KINETIC ENERGY : Associated with motion.

Average KE = TEMPERATURE

Page 19: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

HEAT

• The form of ENERGY that flows between two samples of matter due to their difference in temperature.

• It is measured in Joules. Other units are calories and kJ.

• It cannot be measured directly!

Page 20: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Heat

Heat always flows from warmer (HIGH T) to cooler(LOW T) objects.

Ice gets warmer while hand gets cooler

Cup gets cooler while hand gets warmer

Page 21: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Energy

• The ability to do work.• Energy is measured in Joules (J)• Any change re quires energy. Changes can

be Exothermic or Endothermic• Exothermic changes- release or give off

heat while they occur. (condensation, freezing)

• Endothermic changes Absorb heat as they occur (melting, boiling)

Page 22: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

ENERGY AND CHEMICAL REACTIONS

• EXOTHERMIC REACTIONS: reactions that RELEASE heat as they occur. Example: any combustion.

• ENDOTHERMIC REACTIONS: reactions that ABSORB heat energy as they occur.

Page 23: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Heating and Cooling

• If an object has become hotter, it means that it has gained heat energy.

• If an object cools down, it means it has lost energy

Page 24: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

6. Specific Heat

a. Some things heat up or cool down faster than others.

Land heats up and cools down faster than water

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HEAT CAPACITY

• The amount of heat needed to increase the temperature of a material by 1oC. It depends on the MASS and the CHEMICAL COMPOSITION of the material.

 

 

Page 26: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

SPECIFIC HEAT CAPACITY

• The amount of heat needed to increase the temperature of 1 g of substance by 1 C.

• Depends only on the chemical composition.

 

Page 27: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

SPECIFIC HEAT CAPACITY

MATERIAL SPECIFIC HEAT J/g C

Water 4.18

Alcohol 2.43

Aluminum 0.90

Iron 0.45

Lead 0.13

Sand 0.83

Page 28: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Why does water have such a high specific heat?

Water molecules form strong bonds with each other; therefore it takes more heat energy to break them. Metals have weak bonds

and do not need as much energy to break them.

water metal

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How to calculate changes in HEAT

The heat absorbed or released in a chemical reaction

Q = m x T x CpQ = HEAT

m = mass of substance

T = change in temperature (Tf – Ti)

Cp = specific heat of substance

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Calorimeter

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Bomb Calorimetry

A more sophisticated model is the bomb calorimeter, it has a chamber where a chemical reaction takes place and a device to start the reaction.

Page 32: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

HW answers• 1) 42000 J• 2) 6300J• 3) 5 C• 4) 20 C• 5) 336 g• 6) 14700 J =14.7 kJ• 7) 14.24 %• 8) b • 9)b 10 7J (d)

1) 1

2) 4

3) 3

4) 4

5) 3

6) 3

7) 2

8) 2

9) 4

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Aim: How to determine the melting point of a substance?

Challenge: To determine the melting point of water.

Your write up should include the following components: I. TITLE

II. PURPOSE

III. MATERIALS-

IV. PROCEDURE

V. DATA

VI. CALCULATIONS/GRAPH

VII.CONCLUSION (including a discussion of sources of error.)

 

Page 34: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

What is the freezing point of water?

• How would the mass of the sample affect the melting point? Explain.

• Describe the steps needed to determine the boiling point of water.

• Describe the phase changes that take place as water melts and as water boils.

Page 35: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Vocabulary

• condensation• deposition• freezing• fusion• gaseous phase• heat• heat of fusion• heat of vaporization• kinetic molecular theory

• sublimation• temperature• vaporization• solidification• melt• solid phase• liquid phase

Page 36: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

October 17

• Objective: What are the characteristics of each state of matter?

• How to determine the amount of heat needed to change state?

Page 37: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Phases of Matter

• The structure and arrangement of particles and their interactions determine the physical state of a substance at a given temperature and pressure.

• The three phases of matter (solids, liquids, and gases) have different properties.

Page 38: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

States of Matter

Page 39: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

States of Matter.

Page 40: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Particle diagrams

Page 41: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Phase Change

• DURING A PHASE CHANGE TEMPERATURE REMAINS CONSTANT

• Phase changes• Melting or Fusion: Phase change from

solid to liquid. Endothermic.• Vaporization – Phase change from liquid to

gas. It occurs during boiling. Endothermic.

Page 42: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Phase Changes

• Evaporation: from liquid to gas. It occurs at all temperatures and ONLY at the surface of the liquid. Endothermic.

• Condensation: From gas to liquid. Exothermic.

• Freezing, solidification or crystallization: from liquid to gas. Exothermic.

Page 43: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Special Phase Changes

• Sublimation: from solid directly to gas without changing to liquid first.

• Dry Ice CO2 (s) --> CO2 (g)

• Iodine I2 (s) --> I2 (g)

Page 44: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Special Phase Changes

• Deposition: From gas to solid without going to liquid state.

Page 45: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Special Phase Changes

Page 46: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

HEAT OF FUSION FOR WATER (TABLE B)

• Amount of heat needed to completely melt 1g of water (ice!).

• 334 J/g• 334 Joules of heat are necessary to

completely melt 1 g of water.• HOW MUCH HEAT IS NEEDED TO

MELT 10 g OF WATER?

Page 47: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

HEAT OF VAPORIZATION FOR WATER (TABLE T)

• The amount of heat needed to completely vaporize one g of water at its boiling point.

• 2260 J/g

• Water needs 2260 J of heat per gram to convert to gas!

Page 48: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Summarizing

When there is a change in temperature use

Q = m x C x T

While the substance is melting/freezing use

Q = m x H f

While the substance is boiling/condensing use

Q = m x H vap

Page 49: Temperature Definition Instrument Scales TEMPERATURE Is associated with heat but it is NOT HEAT. IT IS NOT A FORM OF ENERGY!!!! ( Heat is) Review: What.

Do now!

• How much heat is needed to completely melt 10 g of ice at 0 0 C ?

• How much heat is needed to vaporize 10 g of water at 100 0 C ?