Gas Mass & Conservation of MassGas Mass & Conservation of Mass

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Solid

Atomic view

Fixed shapeFixed volume No volume change under pressure

Gas Mass & Conservation of MassGas Mass & Conservation of Mass

Particles fixed in placein regular array

Liquid

Gas Mass & Conservation of MassGas Mass & Conservation of Mass

Takes shape of container(not necessarily filled)Defined volumeSlight volume change under pressure

Particles arranged randomly Free to move while maintaining contact with neighbors

Atomic view

Gas

Gas Mass & Conservation of MassGas Mass & Conservation of Mass

Takes shape and volume of its containerLarge volume changes with pressure

Atomic view

Particles widely separatedMoving fast and independently

Mass MeasurementMass Measurement

Standard Kilogram

http://en.wikipedia.org/wiki/Kilogram

Balances

Independent of location

Mass is the quantity of matter in an object (traditional)

WeightWeight

F = ma

Weight = m x g where g is the gravitational accelerationW = mg

Depends on location as g varies

from place to place

Spring Balance

http://en.wikipedia.org/wiki/MGal

Gas Mass & Conservation of MassGas Mass & Conservation of Mass

Does a gas have mass??

Gas Mass & Conservation of MassGas Mass & Conservation of Mass  Item Measured

MassMass Difference

Identity

A Bag Clip      B Balloon      C Baking Soda + container      D Balloon containing Baking Soda   D-B = Mass of baking

sodaE Bottle + Vinegar      F Bottle + Vinegar + Balloon + Baking

Soda(before addition)

  D+E =  

G Bottle + Vinegar + Balloon + Baking Soda(after addition)

  Is there a difference between F and G?

 

H Balloon + Clip   H-B-A =   

Mass of gas!  

I Bottle + Vinegar + Baking Soda   E+(D-B)= Mass conserved?

J Bottle + Lime + water      

K Balloon + Bottle + Lime + clip(before addition)

  H+J=  

L Balloon + Bottle + Lime + clip (after reaction)

  H+J= Was mass conserved??

         

  VOLUMES MeasuredVolume(mL)

   

M Vinegar used      

N Vinegar + baking soda   N-M =  

O Vinegar + baking soda + sand   O-N =  

Gas Mass & Conservation of MassGas Mass & Conservation of Mass

When 1 ton of Indiana coal (Carbon) is burned to generate electricity,

the amount of carbon dioxide formed is

A. Less than 1 ton

B. Equal to 1 ton

C. More than 1 ton

D. Can’t tell without more information

Gas Mass & Conservation of MassGas Mass & Conservation of Mass

When 1 ton of Indiana coal (Carbon) is burned to generate electricity,

the amount of carbon dioxide formed is

A. Less than 1 ton

B. Equal to 1 ton

C. More than 1 ton

D. Can’t tell without more information

C + O2 → CO2

Gas Mass & Conservation of MassGas Mass & Conservation of Mass

Reactions

NaHCO3 + CH3COOH NaCO3 + H2O + CO2

Sodium bicarbonate + Acetic acid Sodium carbonate + Water + Carbon dioxide

Baking Soda + Vinegar

CaO + CO2 CaCO3

Lime + Carbon dioxide Limestone

Calcium oxide + Carbon dioxide Calcium Carbonate + Heat

+ Heat

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Gas Mass & Conservation of MassGas Mass & Conservation of Mass

Combustion

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Gas Mass & Conservation of MassGas Mass & Conservation of Mass

Gas Mass & Conservation of MassGas Mass & Conservation of Mass

Buoyancy correction

http://en.wikipedia.org/wiki/Buoyancy

In the experiment we expected that the mass would not change as reaction took place according to the principle of conservation of mass.However we observed that the mass of the balloon, bottle, vinegar and baking soda combination decreased as the carbon dioxide was formed and blew up the balloon. The apparent loss of mass was because we did not employ a buoyancy correction.The expanding balloon displaced an equal volume of air

Gas Mass & Conservation of MassGas Mass & Conservation of Mass

Volume of balloon = volume of air displacedMass of air displaced = Volume of balloon x density of airApparent mass loss = Mass of air displaced Mass lost = 4/3 ∏ = 3.8 g

for r = 3.5” = 8.89 cm