chemistry Q4 finals

translation

a body shifts from one point in space to another.

rotation

a body spins around a fixed point

vibration

an object moves rapidly back and forth but stays in a fixed place

what motion happens in gases?

they are free to move all 3 ways.

does transactional motion happen in liquids?

yes, but its limited

what motion happens in solida?

only vibrational energy.

Q9) Will the average vibrational energy of nitrogen gas (N2) at 22°C be greater than, less than, or equal to the average vibrational energy of NaCl at 22°C? Make a claim and support it with evidence.

It will be greater than. Nitrogen is a gas, therefore its particles possess a higher kinetic energy than Nacl, which is a solid lattice.

Fluid

any substance that flows

what are liquids and gases considered as?

fluids

Hydrogen Bonds

a specific type of dipole-dipole attraction results from the interaction of a ___ atom and a highly electronegative atom such as chlorine or oxygen. they are intermolecular forces

permanent dipoles

the ends of molecules are attracted to other molecules in the opposite orientation.

dispersion forces/temporary dipoles/vander wal forces

these form due to random motion of the electron around the nucleus. The atoms are otherwise nonpolar.

intermolecular forces

the attractive force between different molecules.

intramolecular forces

forces that hold atoms within an individual molecule together.

Molecular Solids

consists of molecules that are held together by the relatively weak intermolecular forces. Because of weak molecular connections, these solids tend to be soft and have low melting points.

Ionic Solids

consists of positively and negatively charged ions held together by ionic bonds. This strong attraction results in high melting points and hardness

Metallic Solids

formed via metallic bonds. The properties are highly variable, depending on how the electrons are arranged.

Q11) Explain why carbon dioxide is a gas, water is a liquid, and salt is a solid at room temperature based on how the particles are held together.

Carbon dioxide is a gas due to weak intermolecular forces allowing free movement, water is a liquid because strong hydrogen bonds hold molecules close yet fluid, and salt is a solid due to an incredibly strong ionic lattice holding particles rigidly in place at room temperature.

Crystals

particles are arranged in an orderly, repeating, 3D pattern.

Amorphous solid

lacks an ordered internal structure

Examples of amorphous solids?

Rubber, plastic, and asphalt.

What is cleavage?

the tendency of a material to break along smooth planes parallel to planes of bonds.

What is a Fracture?

the tendency of a solid to break along curved surfaces without definite shapes due to a lack of a flat bonding plane.

Unit Cells

the smallest group of particles within crystal that remains the overall symmetry of the crystal.

Crystal Systems

Tetragonal, Orthorhombic, Monoclinic, Cubic, Triclinic, Hexagonal, Rhombohedral

Types of Unit Cells

Simple Cubic, Body Centered Cubic, and Face centered.

Q12) Why is the arrangement of the constituent atoms or molecules more important in determining the properties of a solid than a liquid or gas? Why are the structures of solids usually described in terms of the positions of the constituent atoms rather than their motion?

Because the particles in a solid are in a fixed position, tightly compacted, therefore they only vibrate.

Phase Change

The transformation from one state of matter to another.

Melting

solid to liquid

freezing

liquid to solid

vaporization

liquid to gas

condensation

gas to liquid

sublimation

solid to gas

deposition

gas to solid

evaporation

liquid to vapor

vapor pressure

the pressure of a vapor in contact with its liquid or solid form.

melting point

the temperature at which a solid becomes a liquid

Allotropes

different physical forms of the same element.

Ductility

the ability to drawn into wires

malleability

the ability to be hammered or pressed into shapes

thermal conductivity

the materials ability to conduct heat

electrical conductivity

materials ability to conduct electricity

Luster

the way light interacts with a materials surface

point defect

an irregularity within a crystal that occurs at a point in the lattice

interstitial defect

extra atoms are stuck where they dont belong

substitution defect

different atoms take the place of existing atoms in the crystal lattice

vacancy defect

atoms are missing from the lattice structure

dislocation

happens when entire planes of atoms get inserted or removed

Q30) You are designing a metal bicycle frame. What properties should the frame have?

1) Aluiminum Alloys (Light + Stiff) 2) Steel Alloy (Durable + Strong) 3) Titanium Alloy (Strength + Corrosion Resistant)

Q32) Why is water a liquid at room temperature while Carbon Dioxide is a gas? What's different about their structures that result in different properties?

The difference in their their physical states primarily due to their molecular structures, resulting into IMF’s.

Surface Tension

The property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of its molecules

Q33) Printers often use surfactants in the printing of paper with ink. Explain why this might be.

To reduce surface tension.

surfactant

a substance that reduces surface tension.

How many times can water bond with its neighbor?

a maximum of 4 times

STP

standard temperature and pressure

Q34) Hydrogen fluoride has a lower b.p than water, even though flouride has a greater electronegativity than oxygen. Why?

Because of the number of hydrogen bonds.

Solvent

the dissolving medium.

solute

the dissolved particles (usually ions).

solvation

the process of ion capture by the solvent

aqueous solution

a solution where water is the solvent

what is the universal solvent?

water.

examples of nonpolar compounds dissolving into other nonpolar compounds.

1) oil in water

2) iodine in hexane

electrolyte

compound that conducts electric currents when dissolved in an aqueous solution or in the molten state.

nonelectrolyte

compound that doesnt conduct electrical currents in aqueous solutions or in molten state.

Example of a strong electrolyte?

Sodium Chloride (NaCl)

Example of a weak electrolyte?

Mercury(II) Chloride (HgCl2)

Example of a Non Electrolyte?

Glucose (C6H12O6)

Hydrate

a solid crystalline compound that containts water molecules as an integral part of its crystal structure

Efflorescence

loss of water by a hydrate

desiccator

a chamber used for maintaining a dry environment in chemistry labs.

silica gel packs

contains hygroscopic chemical silica which absorbs moisture from the air

agitating

induced motion

dissolution rate

the rate at which a solute dissolves

saturated solution

the maximum amount of solute for a given quantity of solvent at a constant temperature and pressure

solubility

the amount of solute that dissolved in given quantity of a solvent at a specified temperature and pressure to produce a saturated solution.

solvated

breaking down into their essential ions

Q42) Compare the concepts of saturated solutions and vapor pressure. how are they similar and how are they different?

Similarities: 1) Dynamic Equilibrium 2) Capacity Limits 3) Temperature Dependent

Differences: 1) Phases involved 2) Physical Nature 3) Medium

Hypoxic Zones

areas in the ocean where the oxygen concentration is so low that animal life suffocates

supersaturated solutiob

contains more solute than it theoretically can hold at a given temperature.

henrys law

S1/P1 = S2/P2

homogeneous mixture

has a uniform appearance and composition

heterogeneous mixture

are not uniform in composition and are not considered solutions

colloid

a heterogeneous mixture containing particles, called the dispersed phase, that are spread out throughout another substance, called the dispersion medium

suspension

a heterogeneous mixture from which particles settle out upon standing

Tyndall effect

the scattering of visible light by particles

aggregrates

clumps