GEAS: Chemistry

Chemistry

Chemistry

is the study of matter and the changes it undergoes.

Scientific Method

is a systematic approach to research.

Nx10^n

Scientific Notation

Significant Figures

are the meaningful digits measured or calculated quantity.

Accuracy

tells how close a measurement is to the true value of the quantity that was measured.

Precision

refers how closely two or more measurements of the same quantity agree with one another.

Matter

is anything that occupies space and has mass.

Substance

A classification of matter wherein there are definite constant properties

Mixture

A classification of matter wherein there are two or more substances

Element

A type of pure substances wherein it cannot be separated by any means

Compound

A type of pure substances wherein two or more substances can be separated.

Homogenous

a type of mixture that has the same proportions of its components in a given amount of sample.

Heterogenous

a mixture in which the composition is not uniform throughout the mixture.

Solid

is a state of matter wherein it has a definite shape and volume because the molecules that make it up the are packed closely together and move slowly

Liquid

is a state of matter wherein it has a definite volume but takes the shape of its container.

Gas

is a state of matter wherein it has neither a definite volume nor a definite shape.

Plasma

a state of matter which is made by heating gas until its electrons have sufficient energy to escape the hold of the positively charged nuclei.

Bose-Einstein Condensate

is a state of matter which has the lowest absolute zero.

Physical Property

is a characteristic of matter that can be observed and measured without changing the chemical identity of the sample.

Chemical Property

is a characteristic of a particular substance that can be observed in a chemical reaction.

Intensive Property

is a property of matter that depends only on the type of matter in a sample and not on the amount.

Extensive Property

is a property that depends on the amount or density of matter in a sample.

Sublimation

The process in which a solid changes directly into vapor without first forming a liquid.

Liquid and Gas

two states of matter which occupies the whole space of available.

Liquid and Gas

which two types of matter fall under the term fluids?

Atom

is the basic building block of matter. It is the smallest particle of element.

Atomos

The term used by Democritus which means uncuttable or inidivisible.

Law of Conservation of Mass

A law which states that matter can be neither created nor destroyed.

Joseph Proust’s Law of Definite Proportions

A law that states: different samples of the same compound always contain its constituent elements in the same proportion by mass.

Joseph Proust

is a French chemist who one who discovered the Law of Definite Proportions

Law of Multiple Proportions

A law which states that two elements can combine to form more than one compound, the two masses of one element that combine with a fixed mass of the other element are in ratios of small whole numbers.

Atomic Number

is the number of protons (or number of electrons) in the nucleus of each atom of an element.

Z

Is the letter or symbol that denotes the Atomic Number of an element.

Mass Number

is the total number or neutrons and protons present in the nucleus of an atom of an element.

A

is the letter or symbol that denotes the mass number of an element.

Mass Number

Number of Protons + Number of Neutrons = _____

Mass Number

Atomic Number + Number of Neutrons = _____

Isotopes

are atoms that have the same atomic number but different mass numbers.

Average mass of an element

the sum of the masses of its isotopes, each multiplied by its natural abundance.

Mole

is the amount of pure substance containing the same number of chemical units, as there are atoms in exactly 12-grams of carbon-12.

Avogadro’s Number

it is the number of units in one mole of any substance which is constantly equal to:

NA = 6.02x10^23 particles/mole

Periodic Table

is a chart in which elements having similar chemical and physical properties are grouped together.

Periods

are the horizontal rows of the periodic table.

Group or Families

are the vertical rows of the periodic table.

Niels Bohr

The concept that electrons revolve around the nucleus in specific paths called orbits or energy levels was proposed by

24.31 amu

Naturally occurring magnesium consists of 78.7% of 24Mg, with atoms of mass 23.98504 amu, 10.13% of 25Mg, with atoms of mass 24.98584, and 11.17% 26Mg, with atoms of mass 25.98259 amu. Calculate the atomic mass of magnesium.

50.4% & 49.6%

Calculate the percentage of bromine atoms that have a mass of 78.9183 amu and the percentage that have a mass of 80.9163 amu. The atomic mass of bromine is 79.909 amu, and these are the only two naturally occurring isotopes.

Metal

is an element that is a good conductor of heat and electricity

Nonmetal

is an element that is a poor conductor of heat and electricity

Metalloids

is an element that is an intermediate of metals and nonmetals

Cation

a positively charged ion, i.e. one that would be attracted to the cathode in electrolysis.

Anion

a negatively charged ion, i.e. one that would be attracted to the anode in electrolysis.

Ion

is an atom or group of atoms that has a net positive or negative charge.

Chemical Formula

are formula used to express the composition of the molecules and ionic compounds in terms of chemical symbols.

Molecular Formula

shows the exact number or atoms of each element in the smallest unit of a substance.

Molar Mass

is defined as the mass (in grams or kilograms) of 1 mole of units (such as atoms or molecules) of a substance.

g/mol or kg/mol

the units of molar mass are

Molecular Mass

it is sometimes called Molecular Weight and is the sum of the atomic masses (in amu) in the molecule.

Percent Composition

is obtained by dividing the mass of each element in 1 mole of the compound by the molar mass of the compound and multiplying by 100 percent.

Chemical reaction

is a process in which a substance (or substances) is changes into one or more new substances.

Reacts with

In writing chemical equations, “plus” sign (+) means

To yield

In writing chemical equations, “arrow” sign means

Solution

is a homogenous mixture of two or more substances

Solute

is the substance present in a smaller amount.

Solvent

is the substance present in a larger amount.

Aqueous Solution

is a solution in which the solute initially is a liquid or a solid and the solvent is water.

Electrolyte

is a substance that, when dissolved in water, results in a solution that can contain electricity.

Nonelectrolyte

does not conduct electricity when dissolved.

85g

What is the mass of 5.00 mol of NH3?

2.01x10^24

Calculate the number of particles on 56.7g of NH3?

35%

Determine the percent composition of nitrogen in NH4NO3?

Concentration of a Solution

is the amount of solute present in a given quantity if solvent or solution.

Molar

or molar concentration, is the number of moles of solute per liter of solution.

Dilution

is the procedure for preparing a less concentrated solution from a more concentrated one.

Synthesis reaction

a type of chemical reaction that occurs when two or more reactants combine to form a single product.

Decomposition reaction

is a reaction in which a compound breaks down into two or more simpler substances.

Single Replacement

sometimes called a single displacement reaction, is a reaction in which one element is substituted for another element in a compound.

Double Replacement

are reactions in which the positive and negative ions of two ionic compounds exchange places to form two new compounds.

Molality

or molal concentration, is the amount of substance dissolved in a certain mass of solvent.

Molarity

is the amount of substance in a certain volume of solution. It is defines as the moles of a solute per liters of a solution.

Molarity

It is also known as the molar concentration of a solution.

Acids

have sour taste, cause color changes in plant dyes, react with certain metals, and react with carbonates and bicarbonates.

Acid

a chemical substance that neutralizes alkalis, dissolves some metals, and turns litmus red; typically, a corrosive or sour-tasting liquid of this kind.

Bases

have bitter taste, feel slippery, and cause color changes in plant dyes.

Base

a substance that can accept hydrogen ions in water and can neutralize an acid.

Neutralization

is a reaction between an acid and a base.

Aqueous

acid-base reactions that produce water and a salt.

Catalyst

A substance added to the solution to speed up chemical reactions

2.0`

Calculate the molality of a solution containing 0.5 mol of solute in 250g of solvent.

0.833

Calculate the molarity of 1.5 L of a 2.5 M solution after it has been diluted to a 4.50 L

Carbonic Acid

The carbon dioxide is soluble in water. The acid formed when it dissolves is called

Combination reaction

the reaction CaO + H2O to Ca(OH)2 is an example of

7

A neutral solution has a pH of

1.0

Calculate the pH of 0.100 M HCl

Antoine Lavoisier

Debunked the phlogiston theory. Uncovered the truth in combustion. Names hydrogen and oxygen. Identified sulfur and predicted silicon. Published the first Chemistry book.

Ampotheric

A substance that can act as both acid and base is called

More than 7

The pH of an aqueous solution of a sodium acetate is

Basicity

The number of hydrogen ions obtainable from a molecule of an acid is called

Antoine Lavoisier

The Father of Modern Chemistry

Dmitiri Mendeleev

A Russian Chemist who created the framework that became the modern periodic table, leaving gaps for elements that were yet to be discovered.