Chemistry Chapter 10 States of Matter

What is standard pressure?

The pressure exerted at sea level in dry air 760. mmHg 760. torr 101.325 kPa 1.00 atm

Define Viscosity

The resistance of a liquid to flow. An increase in temperature will decrease the viscosity.

Define Unit Cell

The smallest portion of a crystal lattice that shows the 3-D pattern.

Define Diffusion

The spontaneous movement of particles of gas caused by motion

What does the speed/velocity of a gas molecule depend on?

The temperature and molar mass of the molecules. Temperature is directly proportional to the speed, molar mass in indirectly proportional.

Define Normal Boiling Point

The temperature at which the vapor pressure is equal to standard pressure (1.00 atm)

Define Boiling Point

The temperature at which the vapor pressure is equal to the external pressure (usually atmospheric pressure). This depends on where you are.

A tin cup will conduct electricity, but the plastic foam cup will not. Why?

The tin cup is a good conductor because its valence electrons are free to flow. The foam cup is a covalent molecular substance and consequently conducts electricity poorly.

Covalent vs Ionic Bonding

Covalent bonding (M+NM) is the sharing of electrons to achieve mutual stability. Ionic bonding (NM+NM) is the attraction between two ions with opposite charges when one atom gives up an electron to the other.

How does a pressure cooker work?

I'm not exactly sure about this one, I'll add an answer tonight.

What is the formula for density?

Mass/Volume

What are the three types of bonding?

Nonpolar covalent, polar covalent, ionic

Name three examples of amorphous solids.

Plastic, butter, glass

What are the seven basic crystalline systems?

Cubic, Tetragonal, Hexagonal, Triclinic, Monoclinic, Orthohombric, Trigonal

What kinds of collisions occur between gas particles and container walls?

Elastic

What is the freezing temperature in Kelvin and Celcius?

-273 degrees Celcius, 0 degrees Kelvin

What is the pressure exerted by a constant number of gas molecules above a liquid or a solid

Equilibrium vapor pressure

Define Dynamic Equilibrium

Evaporation rate = Condensation rate Although there are two opposing processes going on, they are occurring at the same rate. This does not mean that the amount of vapor equals the amount of liquid!

True or False: Liquids with weaker intermolecular forces have higher viscosity.

False, higher intermolecular forces create stronger attraction between molecules, which creates a resistance to flow.

Define Elastic Collision

A collision with no loss of energy

Define Inelastic Collision

A collision with some loss of energy

Define London Dispersion Forces

Nonpolar molecules will also exhibit a weak attraction for one another. The constant motion of electrons within a molecule can create a temporary dipole that attracts to another temporary dipole. This attraction is called a London Dispersion Force.

Define Surface Tension

A force that tends to pull adjacent parts of a liquid's surface together, thereby decreasing surface area to the smallest possible size.

Order the following liquids from highest surface tension to lowest? Explain. Br2, H20, H2S

Not sure about this one exactly, I'll get back to it later today.

Which has a higher viscosity, water or carbon tetrachloride, CCl4

Not sure about this one exactly, I'll get back to it later today.

What is the Kinetic-Molecular Theory of Matter for Gass (5 parts)

1. Gass are made of tiny particles that are far apart. They take a lot of space relative to solids and gases. They are easily compressed. 2. Collisions between gas molecules and container walls are elastic. 3. Gas particles move in continuous, rapid, straight, random motion and therefore have kinetic energy. 4. There are no attraction between gas particles. Any that exists is easily overcome by the KE. 5. The average kinetic energy of a gas particle is directly proportional to substance's temperature.

Define Volatile Liquid

A liquid that evaporates readily at low temperatures. The higher the volatility of a liquid, the weaker the intermolecular forces of attraction between their particles. An increase in temperature will increase evaporation

Define Dipole

A molecule or a part of a molecule that contains both partial positive and partial negative regions

Define Chemical Bond

A mutual electrical attraction between the nuclei and valence electrons of two atoms that binds the atoms together

Define fluid

A nonsolid state of matter in which the atoms or molecules are free to move past each other, as in a gas or liquid (it flows)

What are the properties of metallic crystals?

All metals Metallic bonding

Ideal gas vs Real gas

An ideal gas is a hypothetical gas that perfectly fits all the assumptions of the kinetic-molecular theory. A real gas is a gas that does not.

Define Intermolecular Forces

Attractive forces between molecules

Define Intramolecular Forces

Attractive forces within a molecule

Define Hydrogen Bonds

Bonds that have a large difference in electronegativity, thus creating a large dipole, or a highly polar bond. Basically, bonds between nitrogen/oxygen/fluorine and hydrogen are extra strong and called hydrogen bonds,

Define Crystalline

Consists of crystals, particles arranged in an orderly, geometric repeating pattern

Compare Cl2, Br2, and I2 (at room temperature) and arrange them to the strength of their London Dispersion Forces.

Cl2 is a gas, Br2 is a liquid, I2 is a solid, Cl2 has the lowest molar mass and the weakest LDF. Br2 has the second lowest molar mass and similarly has the second weakest LDF. I2 is solid and has the strongest LDF.

Which physical properties directly correlate with the strength of intermolecular forces?

Density, boiling point, state of matter

Give 2 examples of covalent network crystals.

Diamond (C) and SiO2

Diamond and graphite are both composed entirely of carbon, yet graphite is soft and a diamond is one of the hardest substances known. Explain the difference between these substances in terms of intermolecular fores.

Diamond is a covalent network crystal, meaning the entire object is like one large molecule, and due to the strength of the traditionally intramolecular bonds, very hard. Graphite, on the other hand, relies entirely on London Dispersion forces, which are significantly weaker.

Define Cohesive Forces

Forces of attraction between like molecules (H20 to H20)

Define Adhesive Forces

Forces of attraction between unlike molecules (H20 to glass)

Which is stronger: London Dispersion Forces or Dipole-Dipole Forces

Dipole-Dipole Forces because London Dispersion Forces have extremely short lifespans; once the electrons shift, the dipole disappears.

The molecules on a liquid surface are attracted _________________ and sideways.

Downward

What is the temperature at which solid and liquid forms of a substance exist in equilibrium

Freezing point

Which states of matter can be compressed?

Gas. Water and solid can technically be sometimes compressed, but the effort required is relatively tremendous.

Which states of matter diffuse?

Gases and liquids.

If you knock your glass mug over, it can take the stress without cracking or splitting, but if you really stress it, like dropping it on the floor, it will shatter into randomly shaped pieces. Why?

Glass is amorphous and isn't made of pieces that split easily, so it can handle some minor pressures. However, major stress will break it into random pieces because amorphous solids do not have organized molecules.

As the intermolecular forces in a liquid get stronger, does the viscosity become greater or lesser?

Greater

Define Amorphous

Greek for "without shape"; consist of randomly arranged particles

What are the properties of covalent network crystals?

Held together by covalent bonds.

What are the properties of covalent molecular crystals?

Held together by intermolecular forces Water is an example due to its hydrogen bonding

What are the properties of ionic crystals?

High melting points Any ionic compound Ex. NaCl, MgF2

Do stronger intermolecular forces result in higher or lower boiling points?

Higher

Compare the movements of molecules of liquids and solids.

Liquid molecules move freely and flow. Solid molecules vibrate around fixed points.

What are the van der Waals forces? (The two that are usually considered)

London Dispersion Forces and Dipole-Dipole Forces

What intermolecular forces are acting in F2 and Cl2

London Dispersion Forces.

How is it possible to hard boil an egg without heating it?

I'm not exactly sure about this one, I'll add an answer tonight.

Compare ICL to Br2 because they have approximately the same molar mass. ICL has a higher boiling point. Why?

ICL is polar and therefore has Dipole-Dipole forces whereas Br2 relies entirely on London Dispersion Forces as intermolecular attraction.

Predict what would happen if you placed one tea bag in a glass of hot water and another tea bag in a glass of cold water.

In a glass of hot water, the tea bag's molecules would quickly overcome the intermolecular forces of attraction and spread through the water quickly. In a cup of cold water, the tea does not have the kinetic energy to spread quickly, but it would still spread.

How are London Dispersion Forces related to molar mass?

London dispersion forces are dependent upon the motion of electrons. Therefore, the more electrons, the greater the London forces. With more molar mass comes more electrons.

What are three ways to increase the pressure of a gas in a container?

Increase the temperature/kinetic energy of the gas Decrease the size of the container Add more molecules to the container

Which is stronger: Intermolecular forces or intramolecular forces?

Intramolecular forces. For example, its easier to boil water than it is to decompose.

What are the 4 crystal types?

Ionic, Covalent Network, Covalent Molecular, Metallic

What is the formula relating kinetic energy to mass and velocity?

Kinetic Energy (in Joules) = 1/2 (mass x volume^2) KE = 1/2(m x v^2)

List three physical properties of solids are dependant on both kind of particles that make up the solid and strength of the attractive forces between the particles.

Melting points, conducting electricity, hardness

What is the principal feature of a metallic bond?

Metallic bonds have valence electrons that move freely and thus conduct electricity well.

Which city has higher atmospheric pressure, Pittsburgh or Denver?

Pittsburgh, there are more air molecules over Pittsburgh because it is lower than Denver.

Water is an excellent solvent because of the __________ nature of its molecules.

Polar

In a molecular solid, intramolecular covalent bonds are ____________ than intermolecular attractive forces.

Stronger

An insect is able to walk on water because of a property known as ___________________.

Surface tension

What is the formula for pressure?

Pressure = Force/Area

Define Effusion

Process by which gas particles pass through a tiny opening due to pressure being exerted upon them

What is the Kinetic-Molecular Theory of Matter based on?

The idea that all atoms are moving: vibrating, rotating, translating. The only time something would not be moving would be absolute zero. This movement is kinetic energy, which is proportional to temperature.

How can gas molecules move so freely when other states of matter can't?

The kinetic energy that the molecules have as a gas overcomes any attractive forces that they might have.

Why are the bonds in sodium chloride stronger than those in a molecular solid such as sugar?

Sodium chloride's bonds are strong because they are formed by ions of opposite charges. Sugar relies on hydrogen bonding and other van der Waal forces to create its bonds.

Unlike crystalline solids, amorphous substances may ____________ over a wide range of temperatures before melting.

Soften

What are the three states of matter? (excluding plasma and Bose-Einstein condensates)

Solid, Gas, Liquid

Order the states of matter by decreasing density

Solid, liquid, gas

Define Capillary Action

The attraction of the surface of a liquid to the surface of a solid (an adhesive force)

What does the temperature gas depend on?

The average kinetic energy of the particles of the gas. (directly proportional)

Define Metallic Bonding

The chemical bonding that results from the attraction between metal atoms and the surrounding "sea of electrons" Metallic bonding allows metals to be good conductors of electricity, malleable, and ductile

Define Boiling

The conversion of a liquid to a vapor not only at its surface, but within the liquid as well.

If you bend a tin cup, it can be bent back into its original shape. Why?

The electrons are fluid and can shift back into their original position.

A hot burner on your stove top will melt a plastic foam cup, but it won't melt a tin cup. Why?

The foam cup has molecular bonds, which are weaker intermolecular forces. THis means it has a lower boiling point. On the other hand, tin is a metal and has a higher melting point.

Why does solid ice have a rigid structure?

The hydrogen bonding in water creates rigid structures that make the water get bigger as it becomes solid.

Dipole-Dipole Forces

The partial positive end is attracted to the partial negative end

Define Vapor Pressure

The pressure due to vapor above a liquid. The vapor gets there due to evaporating, which occurs through being heated. Therefore, the greater the kinetic energy of a liquid, the greater the vapor pressure (assuming the environment is sealed).

If you pour steaming hot chocolate into a tin cup, the cup gets too hot to hold. You can always hold a plastic foam cup, even when the hot chocolate is boiling hot. Why?

The tin is a good conductor and absorbs heat because of its metallic bonds. The foam cup has molecular bonds and is a bad conductor. You can hold it because the cup acts as a barrier between your hands and the heat of the hot chocolate.

Why do you feel cold after you get out of the shower? Why does fanning yourself cool you down? Why do you sweat when you have a fever?

The water that your body heats up gains kinetic energy and evaporates faster than the colder water, which makes you cold. Fanning yourself creates kinetic energy, which makes the high kinetic energy particles evaporate faster. You sweat because your body is trying to release heat. The water absorbs the heat and gains kinetic energy like the first question, making you cooler.

Why do Amorphous solids have varying freezing points.

They vary according to how slowly the material cools. Ex. Butter

Define Crystal Structure

Three-Dimensional arrangement of particles of a crystal, represented by a lattice.

What is the process of water to gas called?

Vaporization

Which molecules are moving faster: water at 50 degrees Celcius or water at 20 degrees Celcius?

Water at 50 degrees Celcius

State an example of capillary action.

Water going up the stem of a plant.

What happens as you sip a straw?

When you begin sipping, you are removing molecules from the straw and therefore decreasing the pressure inside the straw. The external pressure is then comparably larger and the liquid is forced up the straw.

Could a change in atmospheric pressure affect your ability to drink from the straw? Explain.

Yes, if the atmospheric pressure goes down, the external pressure decreases and you must remove more molecules to draw out the soda. It becomes harder to drink.