Term
| Atomic and molecular masses are measured in what unit? |
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Definition
unified atomic mass units (u).
carbon-12 atom has a mass of exactly 12.0000 u. |
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Term
| Express unified atomic mass units (u). in kilograms |
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Definition
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Term
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Definition
| the jittery motion of tiny flecks in water; these are the result of collisions with individual water molecules. |
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Term
Most materials _____ when they are heated
Most materials _____ when they are cooled down |
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Definition
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Term
| The freezing point of water is (F & C) |
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Definition
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Term
the boiling point of water is
C & F |
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Definition
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Term
| Describe the concept of Thermal Equilibrium |
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Definition
| When 2 objects placed in thermal contact will eventually come to the same temperature. |
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Term
| What is the Zeroth Law of Thermodynamics |
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Definition
| The zeroth law of thermodynamics says that if two objects are each in equilibrium with a third object, they are also in thermal equilibrium with each other |
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Term
| An object can expand linearly when |
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Definition
| when an object is heated. |
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Term
| If you heat a thin circular ring in the oven, does the hole's ring get smaller or bigger? |
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Definition
| Yes, when the ring is heated , the ENTIRE circle will expand with the rest of the material. |
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Term
Volume expansion:β is the coefficient of volume expansion.
For uniform solids β is approximatly equal to
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Definition
3a
(B is 3x bigger than alpha which is for linear expansion) |
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Term
Thermal Expansion & Water
what is the lowest temp that water can maintain its minimum volume?
what happens if the temp falls lower than that? |
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Definition
1. 4C
2.As it cools further, it expands, as anyone who has left a bottle in the freezer to cool and then forgets about it can testify. |
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Term
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Definition
If a material is fixed at its ends and therefore isunable to expand when the temperature changes. It will then experience large compressive or tensilestress |
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Term
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Definition
the volume of a given amount of gas is inversely proportional to the pressure as long as the temperature is constant.
↑P, ↓V |
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Term
| The volume is linearly proportional to the temperature,as longs as.... |
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Definition
| the temperature is somewhat above the condensation point and the pressure is constant |
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Term
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Definition
| the volume becomes zero at −273.15°C |
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Term
| The concept of absolute zero allows us to define a third temperature scale – the absolute , or ------ scale |
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Definition
Kelvin
(This scale starts with 0 K at absolute zero, but otherwise is the same as the Celsius scale) |
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Term
The kelvin sclae:
1. freezing point of water
2.the boiling point is |
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Definition
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Term
| Finally, when the volume is constant, the pressure is |
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Definition
directly proportional to the temperature
(p=T) |
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Term
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Definition
as the number of grams of a substance that is numerically equal to the molecular mass of the substance
1 mol H2 has a mass of 2 g |
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Term
How to calc the number of moles in a certain mass of material
(formula) |
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Definition
| n (mol)= mass (grams)/molecular mass g/mol |
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Term
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Definition
PV=nRT
n :# of moles
R : universal gas constant
8.315 J/ (mol•K)
0.0821 (L• atm)/ (mol•K)
1.99 calories/(mol•K) |
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Term
Ideal Gas Law:
Standard temperature and pressure (STP) |
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Definition
T=273 K (O°C)
P=1.00 atm
=1.013 x103 N/m2 (Pa)
=101.3 kPa |
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Term
| Volume of 1 mol of an ideal gas is |
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Definition
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Term
The Ideal Gas Law:
If the amount of gas does not change
write the formula |
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Definition
P1V1/T1= P2V2/T2
Always measure T in Kelvins
Pressure must be in absolute pressure:
(in atm)
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Term
the number of molecules in 1 mole is the same for all gases. That number is called Avogadro’s number
(write it) |
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Definition
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Term
Ideal Gas Law:
in Terms of Molecules Avogadro’s Number |
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Definition
PV=NkT
where:
N:# number of moles of a gas x Avogadro’s number
k : Boltzmann’s constant.
k:R/NA = 8.315 J /mol• K /6.02 x 1023/mol
= 1.38 x10-23 J/K |
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Term
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Definition
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Term
| The solid-liquid transition is |
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Definition
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Term
| the liquid-vapor transition is |
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Definition
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Term
| solid-vapor transition is |
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Definition
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Term
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Definition
point where all three phases can coexist in equilibrium. |
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Term
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Definition
| occurs when the fastest moving molecules escape from the surface of a liquid |
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Term
| The inverse process of evaporation is called |
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Definition
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Term
When the evaporation and condensation processes are in _______, the vapor just above the liquid is said to be ________, and its pressure is the _________. |
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Definition
1.equilibrium
2.saturated
3.saturated vapor pressure |
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Term
| The saturated vapor pressure ______ with temperature. |
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Definition
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Term
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Definition
| its saturated vapor pressure equals the external pressure |
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Term
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Definition
| is the pressure each component of a mixture of gases would exert if it were the only gas present. The partial pressure of water in the air can be as low as zero, and as high as the saturated vapor pressure at that temperature. |
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Term
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Definition
is a measure of the saturation of the air. |
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Term
When the humidity is _____, it feels muggy; it is hard for any more water to evaporate. |
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Definition
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Term
The ___ is the temperature at which the air would be saturated with water.
If the temperature goes ____ the dew point, then _______ may occur |
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Definition
1.dew point
2. below
3.dew, fog, rain |
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Term
1.Diffusion occurs from a region of :
Diffusion is the process whereby the concentration of a substance becomes uniform |
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Definition
| 2.high concentration towards a region of lower concentration |
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