Ch. 7/ Solids Liquids and Gases Flashcards
What are the 3 states of matter?
Gases
Solids
Liquids
What is the shape and volume of a gas, solid, and liquid?
• a gas expands to fill its container
• a liquid has a fixed volume that takes the shape of the container and occupies
• a solid has a definite shape and volume
What is the arrangement of particles of a gas, liquid, and solid?
• a gas is randomly arranged, disorganized, and far apart
• a liquid is randomly arranged, but close
• a solid has a fixed arrangement of very close particles
What is the density, particle movement, and interaction between particles of a gas, liquid, and solid?
•Gas
- Low density (<0.01 g/mL)
-particle movement is very fast
- there is no interaction between particles
•Liquid
- High density (~ 1 g/mL)^a
- Particle movement is moderate
- interaction between particles is strong
•Solid
- High density (1-10 g/mL)
- Particle movement is slow
- Interaction between particles is very strong
Existing as a gas, liquid, or solid, depends on:
- The balance between the kinetic energy of its particles.
- The strength of the interactions between the particles.
PROPERTIES OF GASES 📍
What is the kinetic molecular theory of gases?
- A gas consist of particles that move randomly and rapidly.
- The size of gas particles is small compared to the space between the particles.
- Particles exert no attractive forces on each other.
- The kinetic energy of gas particles increases with increasing temperature.
- When particles collide with each other, they rebound and travel in new directions.
- When gas particles collide with the walls of a container, they exert a pressure.
- Pressure (P) is the force (F) exerted per unit area (A).
Pressure = Force/ Area = F/A
1 atmosphere (atm)=
760. mmHG
760. torr
14.7 psi
101,325 Pa
GAS LAWS 📍
What is Boyle’s law? What does it State?
Boyles law: for a fixed amount of gas at constant temperature, the pressure and volume of gas are inversely related.
• if one quantity increases, the other decreases
• the product of the two quantities is a constant, K.
Pressure • volume = constant
P x V = k
GAS LAWS
BOYLE’S LAW
If the volume of a cylinder of gas is halved, the pressure of the gas inside the cylinder doubles.
What equation can explain this behavior ?
Pg 7
P1V1 = P2V2
Initial New
Conditions Conditions
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To learn how to use Boyle’s Law to calculate a new gas, volume, or pressure see slides 8-10.
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GAS LAWS
CHARLES’S LAW
What is Charles’s law?
Charles is law: for a fixed amount of gas at constant pressure, the volume of the gas is proportional to its Kelvin temperature.
• if one quantity increases, the other increases as well
• dividing volume by temperature temperature is a constant, K
Volume/ temperature = constant
V/T= K
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GAS LAWS
CHARLES’S LAW
If the temperature of a cylinder is doubled, the volume of the gas inside the cylinder doubles.
What equation explains this behavior ?
V1/T1 = V2/T2
Initial New
Conditions Conditions
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GAS LAWS
GAY-LUSSAC’S LAW
What is Gay-Lussac’s Law?
Gay-Lussac’s Law: for a mixed amount of gas at constant value, the pressure of a gas is proportional to its kelvin temperature.
• if one quantity increases, the other increases as well
• dividing pressure by temperature is a constant, k
Pressure/ temperature = constant
P/T = k
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GAS LAWS
GAY-LUSSAC’S LAW
Increasing the temperature increases the kinetic energy of the gas particles, causing the pressure exerted by the particles to increase.
What equation explains this behavior?
P1/ T1 = P2/T2
Initial New
Conditions Conditions
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Gas Laws
What is the combined gas law?
• all three gas laws can be combined into one equation.
P1V1/T1 = P2V2/T2
Initial New
Conditions Conditions
• this equation is used for DETERMINING the EFFECT OF CHANGING TWO FACTORS
(e.g., P and T) on the third factor V.
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GAS LAWS
What is the combined gas law used for? ✨✨✨✨ what does that mean ?
P1V1/T1 = P2V2/T2
Initial New
Conditions Conditions
• This equation is used for DETERMINING the EFFECT OF CHANGING TWO FACTORS
(e.g., P and T) on the third factor V.
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Avogadro’s law
What is Avogadro’s law?
Avogadro’s law: when the pressure and temperature are held constant, the volume of big gas is proportional to the number of moles present.
• if one quantity increases, the other increases as well
• dividing the volume by the number of moles is a constant, K
Volume/ Number of moles = constant
V/n = k
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Avogadro’s law
If the number of moles of gas in a cylinder is increased, the volume of the cylinder will increase as well.
What equation can be used to explain this behavior?
V1/n1 = V2/n2
Initial New
conditions conditions
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Avogadro’s law
What is STP and what does it stand for?
See pg 22- 32 for more info
HOW DO I KNOE EHICH TO USE?!?!?
SLIDE 30
• often amounts of gas are compared at a set of standard conditions of temperature and pressure, abbreviated as STP.
• STP conditions are:
1 atm (760 mm Hg) for pressure
273 K (0°C) for temperature
• At STP, 1 mole of any gas has a volume of 22.4 L
• 22.4 L is called the standard molar volume
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INTERMOLECULAR FORCES, BOILING POINT, AND MELTING POINT
What are intermolecular forces?
• intermolecular forces are the attractive forces that exist between molecules
• In order of increasing strength, these are:
1. London dispersion forces.
2. Dipole Dipole interactions.
3. Hydrogen bonding.
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INTERMOLECULAR FORCES, BOILING POINT, AND MELTING POINT
What are the three intermolecular forces?
In order of increasing strength, these are:
1. London dispersion forces.
2. Dipole Dipole interactions.
3. Hydrogen bonding.
Hydrogen bonds are the strongest
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INTERMOLECULAR FORCES, BOILING POINT, AND MELTING POINT
What does the strength of the intermolecular forces determine?
• the strength of the intermolecular forces determines
- If a compound has a high or low melting point and boiling point
- if it is solid, liquid, or gas at a given temperature
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LONDON DISPERSION FORCES
What are London dispersion forces and why do they have weak interactions?
Review charges (✨) pg 36
London dispersion forces are very weak interactions due to the momentary changes in electron density in a molecule
• the change in electron density creates a temporary dipole
• the interaction between these temporary dimples constitutes London dispersion forces
• all covalent compounds exhibit, London dispersion forces
• the larger, the molecule, the larger, the attractive force, and the stronger the intermolecular forces
✨- more electron density in one region creates a partial negative charge (δ-)
✨- less electron density in one region creates a partial positive charge(δ+)
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DIPOLE-DIPOLE INTERACTIONS
What are dipole dipole interactions?
• dipole dipole interactions are the attractive forces between the permanent disciples of two polar molecules.
Pg 37
Formaldehyde
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Hydrogen Bonding
What is hydrogen bonding and when does it occur?
• hydrogen bonding occurs when a hydrogen atom bonded to O, N, or F is electrostatically attracted to an O, N, or F atom in another molecule
• hydrogen bonds are the strongest of the three types of intermolecular forces
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INTERMOLECULAR FORCES
Out of the three intermolecular forces which has the strongest bonds?
Hydrogen bonds are the strongest of the three types of intermolecular forces
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Intermolecular forces review
Name the three intermolecular forces and determine whether their relative strength is weak or strong what they are exhibited by and give an example .
- London dispersion
Relative Strength: weak
Exhibited by: all molecules
Example: CH4, H2CO, H2O
2.Dipole- dipole
Relative Strength: moderate
✨ Exhibited by: molecules with a net dipole
Example: H2CO, H2O
- Hydrogen bonding.
Relative Strength:
Exhibited by: Molecules with an O-H, N-H, or H-F bond
Example: H2O
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INTERMOLECULAR FORCES
BOILING POINT AND MELTING POINT
What is the boiling point and the melting point?
What happens to them when there is a strong intermolecular force?
pg 41 for more info
- The boiling point is the temperature at which a liquid is converted to the gas phase.
- The melting point is the temperature at which a solid is converted to the liquid phase.
✨••• The stronger, the intermolecular forces, the higher the boiling point and melting point
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THE LIQUID STATE
VAPOR PRESSURE
What is evaporation and is it considered an endothermic or exothermic reaction?
(Boiling hot water for too long)
• evaporation is the conversion of liquids into the gas phase
• endothermic reaction – it absorbs heat from the surroundings
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THE LIQUID STATE
VAPOR PRESSURE
What is condensation and is it an endothermic or exothermic reaction?
(Water droplets forming on the outside of a cold glass on a warm day)
• condensation is the conversion of gases into the liquid phase
• exothermic– it gives off heat to the surroundings
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THE LIQUID STATE
VAPOR PRESSURE
What is vapor pressure?
What are some facts about vapor pressure.
- vapor pressure is the pressure exerted by gas molecules and equilibrium with the liquid phase
- • vapor pressure increases with increasing temperature
• the boiling point of liquid is the temperature temperature at which its vapor pressure = 760 mmHg
• stronger than intermolecular forces, the lower the vapor pressure at a given temperature
Pg 46
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THE LIQUID STATE
VISCOSITY AND SURFACE TENSION
What is viscosity?
• viscosity is a measure of a fluid’s resistance to flow freely
• a viscous liquid feels “thick”
• compounds with strong intermolecular forces tend to be more viscous
• substances, composed of a large molecules, tend to be more viscous
📍Any example of viscous compounds?📍
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THE LIQUID STATE
VISCOSITY AND SURFACE TENSION
What is surface tension?
List facts
Pg 49 video 📽️
• surface tension is a measure of the resistance of a liquid to spread out
- The stronger the intermolecular forces, the stronger the surface molecules are pulled down toward the interior of a liquid and the higher the surface tension
- Water has a very high surface tension because of its strong, intermolecular hydrogen bonding
- when small objects seem to “float” on the surface of water, they are held up by the surface tension only.
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THE SOLID STATE
What two categories can a solid fall under ?
• a solid is one of the three states of matter, and can be categorized as either crystalline or amorphous ✨
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THE SOLID STATE
What is a crystalline solid?
• a crystalline solid has a regular arrangement of particles–atoms, molecules, or ions—with a repeating structure
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THE SOLID STATE
What is an amorphous solid?
Pg 53 📽️
• an amorphous solid has no regular arrangement of its closely packed particles.
- lacks atomic structure
Glass rubber and some plastics
• no regular arrangement of their particles
• they can be formed when liquids cool too quickly for regular crystal formation
• very large covalent molecules tend to form amorphous solids, because they can become folded and intertwined
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THE SOLID STATE
What are the four types of crystalline solids? Define them
- Ionic solid: is composed of oppositely charged ions (NaCl)
- Molecular solid: is composed of individual molecules, arranged regularly (H2O)
- Network solid: is composed of a fast number of atoms, covalently bonded together (SiO2)
- Metallic solid: a lattice of metal cations, surrounded by a cloud of e- that move freely (Cu)
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SPECIFIC HEAT
Specific Heat = Heat/ mass • ΔT = cal (or J)/ g • ΔT
Pg 55 for Specific heat of substances
• The specific heat is the amount of heat energy (cal or J) needed to raise the temperature of 1 g of a substance by 1°C
The larger the specific heat, the less its temperature will change when it absorbs a particular amount of heat energy.
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Pg56-67 for
- How to calculate the heat absorbed, given specific heat.
- Pg 65 for Summary or Energy and Phase Changes
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