Teas 7 Chemistry Study Guide

Solid to Liquid

Melting (absorbs energy)

Liquid to Solid

Freezing, (releases energy)

Liquid to Gas

vaporization/absorbs energy

Gast to Liquid

condensation/ release energy

Gas to Solid

deposition/ release energy

Solid to Gas

sublimation

Matter

Anything that takes up space

Mass

the amount of matter in an object

How Does Matter Change?

Matter usually changes state when you add or take away heat, which changes the temperature of the matter

Substance

A single kind of matter that is pure and has a specific set of properties.

examples of substances

1. Water
2. Alcohol
3. Oil
4. Food coloring

Solids

The particles in solids are tightly packed, least compressible

Liquids

Liquids are also a condensed phase, however, in contrast to solids, the particles have some translational kinetic energy, which means they have freedom to move

gas phase

the phase of matter in which atoms or molecules can move essentially independently of one another, most compressible

Which state(s) of matter take the shape of their container?

Liquids and gases take the shape of their containers since, they do not have definite shape and volume. Only solids have definite shape and volume.

SOLIDS

have a definite shape and volume

LIQUIDS

have a definite volume, but can take the shape of their container

GASES

have neither a definite shape nor volume

Which of the following is correct?
(a) Solids have a definite shape and definite volume.
(b) Liquids have a definite volume but no definite shape.
(c) Gases have a definite volume but no definite shape.
(d) Liquids have both definite shape and definite volume.

(a) Solids have definite shape and definite volume.
(b) Liquids have definite volume but no definite shape.

The higher the temperature?

the more energy the molecules have (move particles of matter apart) and the more space they take up

The higher the pressure?

the more the molecules are forced together

Which state of matter has atoms that move freely?

Gas

Which state of matter has atoms that can slide past each other?

Liquid

Which state of matter has atoms that vibrate in place?

Solid

Plasma

often found in the stars, a gas that is ionized, meaning that electrons have been stripped from the atoms

Solute

A substance that is dissolved in a solution.

(sugar is the most comment solute)

Solvent

the substance in which the solute dissolves

(water is the universal solvent)

Hydrophilic

water loving solute

(ex: salt with water)

Hydrophobic

water fearing solute

(ex: oil with water)

Solution

A homogeneous mixture of two or more substances

Solubility

the ability of a solute to dissolve in a solvent

Solubility limit

the amount of a solute that can dissolve in a given amount of solvent

Dilution

process of adding solvent to a solution to decrease the concentration of the solution

Molarity

the concentration of a solute in a solution

(mol/L) (moles of solution/ liters of solution)

Osmosis

Diffusion of water through a selectively permeable membrane, (high to low, passive)

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Cohesion

process of similar molecule surrounding and binding to another molecule

ex: water is going to attract water

Adhesion

process of dissimilar molecules binding to another molecule

ex: water is the universal solvent because of its polarity, many substances can dissolve in water

Atom

The smallest component and the most basic part of matter that still retains its identity

Atomic structure

Atoms have a nucleus and electrons. Its nucleus contains protons and neutrons

Nucleus

The part of the atom that houses the protons and the neutrons

Protons

positively charged subatomic particles

Neutrons

the particles of the nucleus that have no charge. they are neutral and without a positive or negative electrical charge; the part of the atom that gives the atom its isotope identity.

Electrons

The part of the atom that has a negative (-) charge

Ion

An electrically charged atom

Cation

A positively charged ion, lost one or more electrons

Anion

A negatively charged ion, gained one or more electrons

Plasma

Plasma is not naturally found in nature on our earth. Instead, plasma is produced artificially or it is found beyond our atmosphere and universe.

The Properties of Substances

The unique and distinctive properties of substances differentiate them from other substances with their own unique and distinctive properties.

Density

mass/volume

Volume

The amount of space an object takes up

Boiling point

the temperature at which a substance changes from a liquid to a gas

Melting point

The temperature at which a solid becomes a liquid

Conductivity

The ability of an object to transfer heat or electricity to another object.

Heat capacity

the number of heat units needed to raise the temperature of a body by one degree.

Malleability

the ability of a substance to be hammered or beaten into thin sheets

What is a physical property?

a characteristic that can be observed or measured without changing the identity of the substance

What is cellular transport?

the movement of molecules in/out of cells to keep cells alive and maintain homeostasis

Cellular transport is split into two categories

a. Active transport
b. Passive transport

What is active transport?

the movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy. ACTIVE=ENERGY

What is passive transport?

The movement of materials across the cell membrane without using cellular energy. PASSIVE=NO ENERGY

What is diffusion?

The movement of particles from an area of high concentration to an area of low concentration.

What is an example of Diffusion?

For example, when you add a drop of food coloring to water, immediately, the food coloring begins to spread (or diffuse) throughout the water, eventually reaching equilibrium where all areas have the same concentration of coloring:

What is a concentration gradient?

difference in the concentration of a substance from one location to another

What is Kinetic Energy?

the energy an object has due to its motion.

An example of kinetic energy is

running water

Catalysts

speed up reactions

Activation Energy

the minimum amount of energy that is needed for a chemical reaction to occur

Enzymes

proteins that act as catalysts, specific to the reaction that the catalyze and are usually named after the substrate that they act upon

Endothermic reactions

absorb heat

ex: temperature increases when cooking an egg (heat is absorbed from the pan to cook the egg)

Exothermic reactions

release heat

ex: concentration of reactants causing combustion or rain condensation of water vapor into rain releasing energy in the form of heat

Equilibrium

rate of the forward reaction is equal to the rate of the reverse action

Dynamic equilibrium

the forward and reverse reactions are occurring simultaneously

ex: carbon dioxide is dissolved into the liquid form of soda at the same rate as the lqiuid form is being covered into gas (soda bubbles/fiz)

Static equilibrium

concentrations of the reactants and products are not changing

ex: the weight of the body does not change when repositioned because the gravitational constant is the same for all objects

KCl is an example of which type of bond?

ionic

What is an ionic compound?

Ionic compounds are compounds made up of ions that form charged particles when an atom (or group of atoms) gains or loses electrons. A cation is an ion charged positively; an anion is an ion charged negatively.

What is an ionic bond?

Formed when one or more electrons are transferred from one atom to another.

Which of the following is exchanged between two or more atoms that undergo ionic bonding?

Valence electrons

What is an ion?

Ions are formed when an atom gains or loses electrons

What is a negative ion?

A negative ion is created when an atom gains electrons. Electrons have a negative charge.

What is a positive ion?

A positive ion is created when an atom loses electrons. Electrons have a negative charge.

What is a chemical bound?

1. Atoms of the same element may bond together to form molecules or crystalline solids.
2. involves atoms combining to form chemical compounds and bring stability to the resulting product. I

What is a valence electrons?

electrons in the outermost shell

How do you find the number of protons?

Look at the atomic number it is the same.

How do you find the number of electrons?

same as the number of protons.

How to find the number of neutrons in an atom?

To find the number of neutrons, you will need to subtract the atomic number from the atomic mass. Remember that the atomic number is the same as the number of protons, which you have already identified

Where can I find the atomic number of an element?

The atomic number is located above the element symbol.

Where can I find the atomic mass of an element?

The atomic mass can be found underneath the symbol for the element.

What is an electrical charge?

For example, if we have an object made up of 14 protons, which are positive, and 12 electrons, which are negative, then we end up with a net charge of positive 2. We simply add 1 for each proton and subtract 1 for each electron. If the resulting number is positive, we have a net positive charge and if the resulting number is negative, we'll have a net negative charge. Note that neutral particles will make no difference in the net charge.

What does combustion produce?

energy, carbon dioxide, and water

Covalent bonds

nonmetal and nonmetal, when atoms share valence electrons

Ionic bounds are found in what elements?

Ionic bonds form only between metals and nonmetals. That's because metals "want" to give up electrons, and nonmetals "want" to gain electrons.
(found in salts)

Hydrogen bounds are found in what elements?

Hydrogen bonding occurs only in molecules where hydrogen is covalently bonded to one of three elements: fluorine, oxygen, or nitrogen

(these bonds are weak)

A graduated cylinder is used to measure;

Large amounts of volume

Measuring spoons are used to measure;

Small amounts of liquid

Volumetric pipettes are used to measure;

Used to measure small amounts of water

Volumetric flasks are used to measure;

Large amounts of liquid

What is the equation for 'parts per million"

(amount of solute/amount of solution) x 1.0 x 10^6

Which of the following can change with pressure?
a. Adhesion
b. Boiling Point
c. Luster
d. Cohesion

Water's boiling point depends on the pressure!

Chlorine is a

nonmetal