question

Chemistry

answer

The study of composition, structure and properties of matter, the changes in which matter undergoes and the energy accompanying these changes.

question

Sysem Internation

answer

scientific unit of measure
meter --> length
Kelvin --> temperature
moles --> number of particles
Liter --> volume
Amperes --> electric current
pascal --> pressure
joule --> heat
gram --> mass

question

Matter

answer

anything that has mass and occupies volume

question

Mass

answer

the amount of matter an object contains

question

Weight

answer

the force with which gravity attracts matter (not the same as mass)

question

Volume

answer

the amount of three dimensional space an object occupies

question

Temperature

answer

Measures the average kinetic energy

question

Significant figures

answer

Number of digits that you report in the answer of a measurement you are taking or a problem you are solving

question

Captive Zeros

answer

zeroes that are located between nonzero digits are always significant e.g. 1,004 4 sigfigs

question

Leading Zeroes

answer

zeroes located before other numbers are not significant e.g. 0.000005 1 sigfig

question

Trailing zeroes

answer

zeroes located after the last non-zero digit sometimes significant e.g. 32,000. 5 sigfigs because it has a decimal point at the end of it, if it did not it would only have 2 sigfigs

question

Multiplying and dividing with Significant Figures

answer

1. Find the number with the least number of significant figures
2. Round your answer to the least number of significant figures
example: 2.35x3.845x8.9=80.418175 cm^3
only two significant figures 80. is what you should report

question

Addiction and Subtractions for Significant Figures

answer

1. Find the number with the least number of decimal places
2. Round your answer to the least number of decimal places
example: 2.35+3.845+8.9= 15.095
the smallest decimal place is the tenths so the answer would be 15.0

question

Dimensional Analysis

answer

A technique used to convert(or change) units
1. Determine the unit equality
2. Write down the given quantity
3. Determine the proper conversion factor
4. Set-up and solve
example: how many inches are in 37.84 feet?
37.84 feet x 12 inches equals 454.08 inches but
1 1 foot in sigfigs it is only 454.1

question

Accuracy

answer

A measure of how close something is to that true value

question

Precision

answer

a measure of measurements to each other

question

Precent error (Located on the back of the Reference Tables)

answer

accepted-calculated x 100
accepted

question

Particle

answer

a unit of matter

question

Atom

answer

The smallest particle of an element that retains the properties of that element (ALWAYS NEUTRAL)

question

Molecule

answer

The smallest particle of a compound that retains the properties of that compound

question

Solids

answer

Particles are in an ordered geometric arrangement, they have definite shape and volume and the particles are very close together but are in constant motion
l l
l oo l
l oo l

question

Liquids

answer

Particles are in free motion, very close together and take the shape of the container
l l
loool
loool

question

Gases

answer

Particles have free random motion and are usually far apart
l o o l
lo o ol
l o o l

question

Diffusion

answer

Movement of on substance through another high to low

question

Compression

answer

decreased distance between atoms

question

Physical Properties

answer

Can be measured and/or observed without changing the identity or composition of a substance. e.g. color, odor, density, melting/boiling point

question

Extensive Properties

answer

Physical properties that depend on the amount of matter e.g. Mass and volume

question

Intensive properties

answer

Physical properties that do not depend on the amount of matter e.g. Color, luster and density

question

Chemical Properties

answer

Properties that lead to changes in the identity or composition of a substance e.g. Flammability, and ability to rust or oxidize

question

Physical Change

answer

Changes in which the identity and composition of matter are not altered e.g. Physical Changes

question

Chemical Changes

answer

Changes in which the identity and composition of matter are altered; new substances are made as a result of a chemical change e.g. Iron turns to rust

question

Kelvin Scale

answer

The Kelvin is the international unit for temperature. This scale is based on the concept of absolute zero of 0K

question

Heat of Fusion

answer

The amount of heat required to convert a a solid at it's melting point to a liquid without an increase in temperature

question

Heat of Vaporization

answer

The amount of heat required to convert a liquid at its boiling point into vapor without an increase in temperature.

question

Kinetic Molecular Theory

answer

1. They are composed of individual particles that are in continuous, random, straight-lined motion
2. The distance between their particles are so great compared to the value of the individual particles that the value of the individual particles is considered to be negligible (i.e. ideal gas particles d not take up spaces)
3. The particles have no attraction forces between them
4. collisions between gas particles are completely elastic; in other words, an equal amount of energy is transferred between the particles- there is no net gain or loss of energy and the system remains constant

question

Real Gases (like oxygen, nitrogen, etc.)

answer

Do no behave exactly like an ideal gas because they are real
1. particles (atoms/molecules) have attraction for each other
2. particles occupy volume

question

PLIGHT

answer

real gases behave like ideal gases under certain conditions
P= pressure
L= low
I= ideal
G= gas
H= high
T= temperature

question

Pressure

answer

the force applied to an object per unit area ex: pounds per square inch (lbs/inch^2)

question

STP (Standard Temperature and Pressure)

answer

conditions most often used to study or test a chemical
Standard Temperature- 273 K
Standard Pressure- 1atm= 760 mmHg= 101.3 kPa

question

Vapor Pressure

answer

The pressure exerted as a liquid changes into a gas (as temperature increase vapor pressure increases)

question

Boiling Point

answer

The temperature at which the vapor pressure of a liquid is equal to the pressure pushing down on the surface of the liquid. The normal boiling point of a liquid is the temperature at which the vapor pressure equals standard pressure. As vapor pressure goes up the boiling point will increase

question

Boyle's Law (pressure acting on volume)

answer

At constant temperature, as pressure on a gas increases the volume decreases

question

Charles' Law (temperature acting on volume)

answer

At constant pressure as the temperature of a gas is increased volume increases

question

Gay-Lussac's Law (temperature acting on pressure)

answer

At constant volume, as the temperature of a gas increases the pressure increases

question

Combined Gas Law

answer

P1V1 = P2V2 (on the reference table)
T1 T2

question

Avogardo's Law

answer

Equal volumes of gases at the same temperature and pressure contain an equal number of gas particles: NUMBER TO REMEMBER 6.02 x 10^23

question

Democritus

answer

All matter is composed of tiny, indivisible particles he called atomes. His idea was dismissed by other Greek Philosophers including Aristotle

question

Antoine Lavoisier

answer

Law of conservation of mass/matter: Matter is neither created nor destroyed

question

Joseph Louis Proust

answer

Law of definite proportions: A given compound always contains the same elements in the same proportions by mass. The ratio is always fixed

question

Joseph Dalton

answer

The properties of matter can be explained in terms of atoms

question

Dalton's Atomic Theory of Matter

answer

1. Each element is composed of extremely small, indivisible particles called atoms
2. All atoms of a given element are identical, but they are different from those of any other element
3. Atoms are neither created nor destroyed in any chemical reaction
4. A given compound always has the same relative numbers and kinds of atoms

question

J.J. Thomson

answer

Cathode Ray Tube Experiment. passed an electrical curent through a glass tube containing different gases at low pressure with magnetic plates on either side of the tube. Concluded that the cathode ray was made up of negatively charged particles

question

Ernest Rutherford

answer

Gold Foil Experiment. Aimed a beam of alpha particles at an extremely thin piece of gold foil and came to two important conclusions:
1. an atom is made up of mostly empty space
2. the majority of an atom's mass and all of it's positive charge are concentrated in a central core called the nucleus

question

Subatomic Particles

answer

Protons- positive charge, located in the nucleus and has a mass of 1
Neutrons- has no charge, located in the nucleus and has a mass fo 1
Electron- has a charge of negative one, located outside the nucleus and has a mass of 1/1840

question

Atomic number

answer

The number of protons in the nucleus of an atom. The identity of an atom is determined by it's atomic number. Ex: every carbon atom has six protons

question

Mass number

answer

The sum of the protons and neutrons in an atom. The number of neutrons can be determined by subtracting the atomic number from the mass number. If you see element-# that is showing the mass number

question

Isotope

answer

Atoms/elements with the same number of protons, but different number of neutrons
Ex. Carbon-12, Carbon-13, Carbon-14

question

Ions

answer

When an atom gains or loses an electrons and has a net positive or negative charge. They have a charge either positive or negative

question

Average Atomic Mass

answer

This is weighted average of the naturally occurring isotopes for an element. This weighting is a result of their precent abundances on Earth.

question

Principle Energy Levels

answer

Describe the approximate distance from the nucleus. The farther away fromt he nucleus, the more energy associated with that level.
- Energy levels are designated with the letter n; n can be the numbers 1-7
-1 is closest to the nucleus and has the least amount of energy associated with it

question

Sublevels

answer

Describes the shape of the electron cloud or orbital
-sublevels designated s,p,d,f
-s has the lowest energy associated with it while f has the highest

question

Orbitals

answer

Each sublevel may contain one or more orbitals (or electron clouds) having different spatial orientations. These are the areas of highest probability of finding electrons

question

Ground State

answer

When the atom (e^-) of an element occupies the lowest energy levels 1st (in order). Elements are in their most stable state when in the ground state

question

Excited State

answer

When the atom absorbs energy and moves of jumps up energy level(s), they are considered to be int eh excited state (not in order). All atoms want to be in the most stable state possible. In order for an atom to be go back to ground state from the excited state the atom must release the energy they had originally absorbed. The energy is released in a form of light that is characteristic to each element.

question

Dmitri Mendeleev

answer

Dmitri Mendeleev arranged elements by increasing atomic mass and similar chemical properties. He found arranged this way had repetitive patterns. At this time, only 70 elements had been discovered. If no known elements seemed to "fit" in a place that went with the patterns. Mendeleev would leave the space blank and elements that had not yet been discovered that fit this pattern were put in these spaces.

question

Henry Moseley

answer

Henry Moseley determined the atomic number for all elements. He proposed the elements in the periodic table should be arranged by increasing atomic numbers which turnet out to be more accurate. This is how the Periodic Table is arranged today

question

Periodic Law

answer

When elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic trend.

question

Metals and Non metals

answer

More than two thirds of all elements are metal. Metals are shiny, malleable, ductile, good conductors of heat and electricity, low ionization energy, lose electrons and form positive ions. Non-Metals are dull, brittle, poor conductors of heat and electricity, have high ionization levels, like to gain electrons and form negative ions.

question

Metalloids

answer

These are the elements surrounding the stair case, between the metals and non-metals. They have both metallic and non-metallic properties. They include: B, Si, Ge, As, Sb and Te. Metals are located to the left and non-metals are located to the right.

question

Common group names

answer

Group 1- Alkali Metals (no including H)
Group 2- Alkaline Earth Metals
(^These groups from strong basses)
Group 17- Halogens form Salts
Group 18- Noble Gases- Chemically un-reactive inert due to filled valence shells. They exist as monatomic molecules

question

BrINClHOF

answer

These are elements that naturally exist as diatomic molecules. Br2 I2 N2 Cl2 H2 O2 F2

question

Atomic radius

answer

One-half the distance between the nuclei of two identical atoms when they are joined together (i.e. the distance from the nucleus of atoms to the valence shell)

question

Ionization Energy

answer

The energy required to remove an electron from an atom in the gas phase. The energy need to remove the first electron is called the first ionization energy; to remove the second electron is called the second ionization energy, and so on.

question

Electronegativity

answer

An atom's attraction for electrons when chemically bonded with another atom.

question

Group Trends

answer

1. As you move down a group the atom's radius increases. This is because an increase in the number of occupied energy levels.
2. As you move down a group IE and EN decrease. This ia because the increased distance between the protons in the nucleus and the valence electrons.
3. As you move down a group metallic properties increase.

question

Period Trends

answer

1. As you move from left to right within a period, the atomic radius decreases. This is because a greater molecular charge.
2. As you move from left to right within a period, the IE and EN both increase. This is because of the decreased distance between the protons and electrons

question

Shielding Effect

answer

When the innermost electrons block the attractive force of the protons on the valence electrons

question

Kernel

answer

the innermost electrons and nucleus

question

Octet Rule

answer

Atoms acquire eight valence electrons by taking or sharing electrons; they want to have an electron configuration like that of the closest noble gas. Most atoms are stabilized with 8 valence electrons. (Exceptions: H, He, Li, Be, B (these only need two)

Chemistry Questions And Answers – Flashcards

Unlock all answers in this set

Haven't found what you were looking for?

Search for samples, answers to your questions and flashcards