Ch1-VideoNotes

Uncertainty in Measurement

1. A digit that must be estimated is called uncertain. A measurement always has some degree of uncertainty. 2. Last digit is always an estimate

Mixtures are

1. Each substance in a mixture retains its chemical identity and properties. 2. In contrast to a pure substance, which by definition has a fixed composition, the composition of a mixture can vary. A cup of sweetened coffee, for example, can contain either a little sugar or a lot. 3. The substances making up a mixture are called components of the mixture. 4. Some mixtures do not have the same composition, properties, and appearance throughout. Rocks and wood, for example, vary in texture and appearance in any typical sample. Such mixtures are heterogeneous 5. Mixtures that are uniform throughout are homogeneous.

Matter

1. The physical material of the universe 2. Anything that has MASS and occupies SPACE

Celsius scale

1. The temperature scale on which water freezes at 0 degrees and boils at 100 degrees at sea level

volume is

1. the amount of space an object occupies

chemists

(1) make new types of matter: materials, substances, or combinations of substances with desired properties; (2) measure the properties of matter; and (3) develop models that explain and/or predict the properties of matter.

Matter is described as

1. Physical State (gas/liquid/solid); and 2. Compositions (element/compound/mixture)

diatomic molecule

1. a molecule that consists of two atoms of the same element

Least certain measurement

1. limits the certainty of the calculated quantity and thereby determines the number of significant figures in the final answer

chemical change

Any time something burns, it is a ____________ _____________

Hydrogen is

1 H 1.008 1. lightest element so smallest mass 2. It also does not take up much space

chemical change

1. A change in matter that produces one or more new substances 2. examples include: combustion, oxidation, decomposition 3. It's a change in the internal structure of matter

Accuracy

1. A description of how closely a measurement is to the true value of the quantity measured.

heterogeneous mixture

1. A mixture that is not uniform in composition; 2. components are not evenly distributed throughout the mixture 3. each component still retains it's composition and properties; it may have only changed it's form (ex: dissolving salt in water) ex: vegetable soup, ice in soda, blood, soil

Element

1. A molecule composed of one kind of atom; 2. substances that cannot be broken into simpler units by chemical reactions. 3. Metal or Non-metal 4. 118 known elements Can be an atom (Ne) or a molecule (two of the same atom-example O2) Ex: Oxygen, Hydrogen, Iron

Elements

1. A molecule composed of one kind of atom; cannot be broken into simpler units by chemical reactions. 2. only about 100 elements\ 3. Each element is composed of a unique kind of atom (no two elements have the atoms configuration)

Distillation

1. A process that separates the substances in a solution based upon their DIFFERENT boiling points into separate homogeneous products

Chromatography

1. A technique that is used to separate the components of a mixture based on the tendency of each component to travel or be drawn across the surface of another material. 2. It produces a PHYSICAL CHANGE, not a chemical one

Joule (J)

1. A unit of energy: 1 J = 0.239 cal; 1 cal = 4.184 J. 2. a 2-kg mass moving at a velocity of 1 m/s possesses a kinetic 3. Because a joule is so small, often use kilojoules (kJ) in chemistry

scientific theory

1. A well-tested explanation for a wide range of observations or experimental results. 2. a model that has predictive powers and that accounts for all the available observations. A theory also generally is consistent with other, perhaps larger and more general theories. 3. no theory can be proven to be absolutely true.

significant figures

1. All the digits that can be known precisely in a measurement, plus a last estimated digit 2. The greater the number of sig/figs, the greater the precision implied for the measurement 3. In any measurement that is properly reported, all nonzero digits are significant.

physical changes

1. Can be used to separate a mixture into pure compounds but it will not break compounds into elements 2. examples: Distillation, filtration, chromatography

Conversion factors of volumes

1. Can involve converting from one measure to a different one Ex 1: Wanting mass in grams and given inches cubed Step 1: Mass = density x volume = density is in g/cm^3 = volume is not given but the length is given in inchs Step 2: Calculate the volume in inches by cubing Step 3: Plug the numbers into the mass formula and add the conversion factor

Nature of energy

1. Electrons in an atom can only occupy certain orbits 2. Electrons in permitted orbits have specific "allowed" energies 3. Energy is only absorbed or emitted in such a way as to move an electron from one "allowed" energy state to another 4. Does not have mass 5. Cannot be held

exact numbers

1. Numbers that have no uncertainty 2. have an infinite number of significant figures ex: 12 eggs = 1 dozen 1000 grams = 1 kilogram 2.54 cm = 1 inch 1 meter (m) = 100 centimeters (cm) 1 kg = 2.2046 lbs 3. Result from counting (exact no of marbles in a jar) 4. The number 1 in any conversion factor

Submicroscopic

1. Refers to the realm of atoms and molecules, which is a realm so small that we are unable to observe it directly with optical microscopes 2. Deals with atoms & molecules

Hydrogen properties

1. So different from other elements it is not grouped into any families 2. Rarely found on Earth as a pure element 3. Gas 4. Highly Flammable 5. Very light 6. Boiling point: -253 degrees celsius

Volume

1. The amount of SPACE an object takes up. 2. The volume of a cube is its length cubed, Thus, the derived SI unit of volume is the SI unit of length, m, raised to the third power. 3. Smaller units, such as cubic centimeters, cm3 (sometimes written cc), are frequently used in chemistry. 4. volume unit used in chemistry is the liter (L), which equals a cubic decimeter, dm cubed, and is slightly larger than a quart. (The liter is the first metric unit we have encountered that is not an SI unit.) 5. 1mL = 1 cm cubed =

Density

1. The amount of mass in a unit volume of a substance 2. Densities of solids/liquids expressed as: - grams/cubic centimeter (g/cm^3) - grams/millileter (g/mL) 3. Density of Water = 1.0 g/mL 4. are temperature dependent because volumes change with a change in temperature 5. temperature should be specified when reporting temperature 6. If not temperature specified, assume 25degrees Celsius (room temperature) Density = Mass/Volume

Atoms

1. The building blocks of matter. 2. Made up of protons, electrons, and neutrons.

Electrolysis of water

1. The decomposition of water into oxygen and hydrogen gas due to an electric current being passed through the water 2. Breaks down into it's component elements: Hydrogen and Oxygen 3. The VOLUME (space) of HYDROGEN is 2 times the volume of water collected because there are 2 hydrogen atoms for each oxygen atom

Precision

1. The degree to which repeated measurements show the same result. 2. how closely individual measurements agree with each other

law of constant composition (law of definite proportions)

1. The observation that the elemental composition of a compound is always the same. 2. French chemist Joseph Louis Proust (1754-1826) first stated the law in about 1800. 3. Regardless of its source—nature or a laboratory—a pure compound has the same composition and properties under the same conditions. Both chemists and nature must use the same elements and operate under the same natural laws. 4. When two materials differ in composition or properties, either they are composed of different compounds or they differ in purity.

scientific law

1. When nature behaves in a certain way over and over again, under all sorts of different conditions, we can summarize that behavior in a scientific law. 2. For example, it has been repeatedly observed that in a chemical reaction there is no change in the total mass of the materials reacting as compared with the materials that are formed; we call this observation the law of conservation of mass. 3. It is important to make a distinction between a theory and a scientific law. On the one hand, a scientific law is a statement of what always happens, to the best of our knowledge. A theory, on the other hand, is an explanation for what happens. If we discover some law fails to hold true, then we must assume the theory underlying that law is wrong in some way.

physical change

1. a change of matter from one form to another without a change in chemical properties 2. there is no change to the composition of the substance (it is the same substance before and after the change) 3. All changes of state are physical changes ex: evaporation of water

standard deviation

1. a computed measure of how much scores vary around the average score 2. the smaller the standard deviation, the more confidence in the measurements

Temperature

1. a measure of the hotness or coldness of an object, 2. is a physical property that determines the direction of heat flow. 3. . always flows spontaneously from a substance at higher temperature to one at lower temperature. 4. Typically measured in Celsius or Kelvin

cubic decimeter

1. a metric unit of capacity, formerly defined as the volume of one kilogram of pure water under standard conditions; now equal to 1,000 cubic centimeters 2. slightly larger than a quart

homogeneous mixture

1. a mixture that is uniform in composition through out the material; 2. components are evenly distributed 3. components are not easily distinguished 4. NOTE: A Pure Substance will have the same AMOUNT of components (never changes) but a homogeneous mixture will be uniform but can have varying amounts of components The amount of salt water can vary, as an example) Examples: Salt Water, White gold, steal, vodka, rain

intensive properties

1. a physical property that remains the same no matter how much of a substance is present Ex: density, boiling point, color, odor, specific gravity

intensive properties

1. a physical property that remains the same no matter how much of a substance is present 2. useful to chemists because they can help to identify substances ex: color, smell, ductility, malleability, boiling point, density, melting point

extensive properties

1. a property that IS dependent on the amount of substance present ex: mass, length, volume, energy

SI units

1. a system of physical units ( SI Units ) based on the meter, kilogram, second, ampere, kelvin, candela, and mole, 2. together with a set of prefixes to indicate multiplication or division by a power of ten.

Mixture

1. are combinations of two or more substances in which each substance retains its chemical identity. 2. can be combination of elements and compounds

Chemical Properties of Matter

1. characteristics that can be observed when a substance interacts with another substance and NEW MATTER IS FORMED 2. ability to react; 3. inability to react; 4. usually hidden

Properties of Oxygen

1. gas (colorless, odorless, tasteless), 2. slightly heavier than air, 3. slightly soluble in water, 4. does not burn but will support combustion 5. Gas 6. Boiling point: -183 degrees Celsius

Burrette

1. graduated glass tube, 2. commonly having a stopcock at the bottom, 3. used for accurately measuring or measuring out small quantities of liquid. 4. Used acid/base titration

State of Matter: Solid

1. has a definite shape 2. has a definite volume 3. is NOT compressible to any appreciable extent 4. held tightly together, usually in definite arrangements in which the molecules can wiggle only slightly in their otherwise fixed positions.

State of Matter: Liquid

1. has a distinct volume independent of its container, 2. assumes the shape of the portion of the container it occupies, and 3. is not compressible to any appreciable extent. 4. the molecules are packed closely together but still move rapidly. 5. The rapid movement allows the molecules to slide over one another; thus, a liquid pours easily

State of Matter: Gas (vapor)

1. has no fixed volume or shape; rather, it uniformly fills its container. 2. can be compressed to occupy a smaller volume, or it can expand to occupy a larger one 3. molecules are far apart and moving at high speeds, colliding repeatedly with one another and with the walls of the container. 4. Compressing a gas decreases the amount of space between molecules and increases the frequency of collisions between molecules but does not alter the size or shape of the molecules.

significant figures multiplication/division

1. he result contains the same number of significant figures as the measurement with the fewest significant figures. 2. When the result contains more than the correct number of significant figures, it must be rounded off.

Water properties

1. high heat capacity, 2. high heat of vaporization, 3. polar solvent properties, 4. reactivity, 5. cushioning 6. Non Flammable 7. Boiling Point: 100 degrees Celsius

A graduated cylinder

1. instrument used to measure volume of a liquid and to deliver variable volumes

Mass

1. is a measure of the amount of material in an object. 2. The SI base unit of mass is the kilogram (kg), which is equal to about 2.2 pounds (lb). 3. 1 kg = 2.2 lbs 4. This base unit is unusual because it uses a prefix, kilo-, instead of the word gram alone. 5. We obtain other units for mass by adding prefixes to the word gram.

property

1. is any characteristic that allows us to recognize a particular type of matter and to distinguish it from other types

Derived units are

1. is obtained by multiplication or division of one or more of the base units. 2. We begin with the defining equation for a quantity and, then substitute the appropriate base units. 3. For example, speed is defined as the ratio of distance traveled to elapsed time. Thus, the derived SI unit for speed is the SI unit for distance (length), m, divided by the SI unit for time, s, which gives m/s, read "meters per second." 4. Two common derived units in chemistry are those for volume and density.

Kelvins scale

1. is the SI temperature scale, and the SI unit of temperature is the kelvin (K). 2. Zero on the Kelvin scale is the temperature at which all thermal motion ceases, a temperature referred to as ABSOLUTE ZERO 3. Absolute zero on Celsius scale is -273.15 degrees Celsius 4. The freezing point of water, 0 °C,0 °C, is 273.15 K 5. Do not use DEGREES with Kelvin K = degree celsius + 273.15

pure substance

1. matter that has distinct properties and a composition that does not vary from sample to sample. 2. is either an ELEMENT or a COMPOUND 3. Cannot be separated into other kind of matter by any physical process 4. Can only be changed CHEMICALLY 5. The properties do not change EX: Water and table salt (sodium chloride) are examples of pure substances.

Significant Figure Rules

1. non-zeros are always significant 2. zeros between two other sig figs are significant ex: 1005 = 4 sig/figs 3. zeros at the BEGINNING of a number ARE NEVER significant. the just indicate the position of the decimal point ex: 0.02 = 1 sig/fig 0.0026 = 2 sig/figs 4. zeros at the END of a number after the decimal point are significant ex: 0.0200 = 3 sig/figs 3.0 = 2 sig/figs 4. If a number ends with zeros but there are no decimal points, usually indicates not significant

3 elements of the human body

1. oxygen, carbon, hydrogen 2. make up 90% of the mass of the human body

Compounds

1. substances composed of two or more elements; 2. they MUST contain two or more kinds of atoms 3. Water, for example, is a compound composed of two elements: hydrogen and oxygen. 5. can be MOLECULES (H20-water) or IONS (NaCL-table salt), Ammonia 6. can be part of a mixture but compounds by themselves are not a mixture

kinetic energy

1. the energy an object has due to its motion 2. The magnitude of kinetic energy, Ek, of an object depends on its mass, m, and velocity, v 3. the kinetic energy of an object increases as its velocity or speed** increases. 4. For a given velocity, the kinetic energy increases with increasing mass. Thus, a large truck traveling at 65 mi/h has greater kinetic energy than a motorcycle traveling at the same velocity because the truck has the greater mass.

Potential Energy (PE)

1. the energy stored in an object because of its position or composition 2. Potential energy is, in essence, the "stored" energy that arises from the attractions and repulsions an object experiences in relation to other objects.

work

1. the energy transferred when a force exerted on an object causes a displacement of that object, 2. is energy used to cause an object to move against an opposing force 3. as the product of the force exerted on the object, F, and the distance, d, that it moves work (w) = F (force) x d (distance) force can be push or pull (gravity is an example)

electrostatic potential energy

1. the most important form of potential energy in molecules is electrostatic potential energy (d = distance between particles, Q = charges of particles) 2. arises from the interactions between charged particles.

Mass

1. the quantity of matter present in an object 2. measure in kg (so it's associated with weight/density)

significant figures addition/subtraction

1. the result has the same number of decimal places as the measurement with the fewest decimal places. 2. When the result contains more than the correct number of significant figures, it must be rounded off

inexact numbers

1. those numbers whose values have some uncertainty; 2. obtained by measurement 3. occur due to equipment error or human errors UNCERTAINTIES ALWAYS EXIST IN MEASURED VALUES

Molecule

1. two or more atoms held together by covalent bonds 2. can be an element (02-oxygen) or a compound (H2O-water)

Pipette

A glass or transparent plastic tube used to accurately measure small amounts of liquid

heterogeneous, compounds

A grapefruit is an example of a ____________ mixture of ___________

flammability

A material's ability to burn in the presence of oxygen

Filtration

A process that separates materials based on the size of their particles.

Scientific Method

A series of steps followed to solve problems including collecting data, formulating a hypothesis, testing the hypothesis, and stating conclusions.

periodic table

A table that shows the elements, their atomic number, symbol, and average atomic mass; elements with similar chemical properties are grouped together.

Chromatography

A technique that is used to separate the components of a mixture based on the tendency of each component to travel or be drawn across the (SOLID) surface of another material. ex: dyes adhering to paper

significant figures

All the digits that can be known precisely in a measurement, plus a last estimated digit

chemical change

CH4 (methane) reacts with oxygen to form carbon dioxide and water vapor, when combusted in a Bunsen burner.

Examples of physical change

Changes of state, temperature or volume (melting, freezing, sublimation, condensation, vaporization)

molecules

Chemicals that result from atoms linking together to form a specific shape

diatomic elements

H2, N2, O2, F2, Cl2, Br2, I2 1. Elements that exist naturally as two-atom molecules

Structure of Matter

How the atoms of the elements are arranged within the sample of matter.

physical vs chemical properties

Physical- melting & boiling point, solubility, odor, color and density Chemical- reactivity of molecules resulting in change in composition

Potential vs. Kinetic Energy

Potential: stored energy Kinetic: energy of motion

Energy

The ability to do work or transfer heat

Chemistry

The study of the properties and behavior or matter

2. Burning of wood

Which is an example of a chemical change? 1. Pulverizing (crushing) rock salt 2. the burning of wood 3. the dissolving of sugar in water 4. melting of popsicle on a warm sunny day

physical property

a quality or condition of a substance that can be observed or measured without changing the substance's composition

Hypothesis

a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.

separation of mixtures

can be done based upon properties

Properties

characteristics of the substance under observation

extensive properties

dependent on the amount of substance present (mass, length, volume)

syringe

instrument (tube) for introducing or withdrawing fluids from the body

heat

is the energy used to cause the temperature of an object to increase

macroscopic

large enough to be visible to the naked eye (ant. microscopic)

volume formula of cube

length x width x height Cube = Length cubed

What 5 elements constitute 90% of earth's crust (including oceans & atmosphere)?

oxygen, silicon, aluminum, iron, and calcium

SI prefixes

prefixes that can be used with SI base units to form new units that are greater than or less than the base units by some multiple of 10

3 states of matter

solid, liquid, gas

composition of matter

the types and amounts of simpler substances that make it up

volumetric flask

used for making liquid solutions of precise volumes