Matter and the Chemical Elements Chapter #3 Matter and the Chemical Elements

Matter Anything occupying space and having mass. Matter exists in three states. Solid Liquid Gas Plasma

State Interconversion evaporation melting Solid Liquid gas Heat of fusion Heat of vaporization Freezing condensation Law of Conservation of Energy Energy cannot be created nor destroyed. This means that the energy to melt ice is the same as the energy released when water freezes. Examples: Pineapple Express and farmers watering their crops to prevent crops freezing.

Solid State Strong cohesive forces Particles in fixed lattice positions Constant shape Constant density Constant volume Minimal compressibility Little thermal expansion

Gas/Liquid Comparison Liquid state Gaseous state Particles are close together Not held in fixed positions Take the shape of container Have fixed volume Little compressability Small thermal expansion Particles are far apart Completely fill container Easily compressed Moderate thermal expansion

Classification of Matter Homogeneous Heterogeneous Substance Solution Element Compound

Elements Elements are pure substances made up of identical atoms. There are 115 known kinds of atoms. Each has its own symbol. The first character in an atoms symbol is an uppercase letter that corresponds the first letter of the elements name. Most elements have a second character in their symbol which is is a lowercase letter usually the second letter of the elements name.

Element Names Elements discovered long ago have names and symbols with Latin or other origins, such as Au for gold (from aurum, meaning “bright dawn”), or Pb for lead (plumbum). Tungsten has a symbol of W, which is the first letter of its German name, wolfram. Symbol and names for the known atoms are given in front cover of textbook

Periodic Chart You can also find these symbols and names in the periodic table inside the front cover of your text although this chart does not have names provided. Metallic Properties- maleable, ductile, Metallic luster, conducts heat and electricity Nonmetallic properties-brittle, non-luster, non-conductors Group 1 Active Metals Group 2 Alkaline Earth Metals Group 17 Halogens

Subatomic Particles What are the atoms made of? Atoms are composed of subatomic particles most of which exist outside the stable structure of atoms for very short periods of time. Three subatomic particles are of interest to chemists: The proton (p) The neutron (n) The electron (e-)

Subatomic Particles 1 amu = 1.67 x 10-24 g Neutrons and protons are about 2,000 times larger than electrons. Atoms have a dense heavy, positively charged nucleus containing the neutrons and protons. Outside the nucleus are the small, negatively charged electrons.

Combining Atoms What happens when we combine atoms? When two or more different types of atoms combine compounds are formed. In a compound formula we write the symbol for each atom type present in the compound, if more than one atom of a given type then a subscript is used to indicate the number of each atom. e.g. NH3 H2O SO2 CH4

Atomic Number Atoms have no overall charge so contain the same number of protons (+) as electrons (-). The number of protons in the nucleus of an atom is called the atomic number It is given the symbol Z. All atoms of a given type or element have the same atomic number (Z). The periodic table arranges atoms in order of atomic number.

Mass Number Neutrons have no electrical charge. For a given atom type the number of neutrons may vary. The sum of the number of neutrons and protons in an atom is called the mass number. It is given the symbol A. Atoms with the same number of protons but different numbers of neutrons in their nucleus are called isotopes.

BOHR MODELS OF HYDROGEN (The three isotopes of hydrogen)

BOHR MODELS OF HYDROGEN P P P N N N N N P N Hydrogen-1 Hydrogen-2 Hydrogen-3 2 3 1 H H H

BOHR MODELS OF HYDROGEN P P P N N N N N P N Hydrogen-1 Hydrogen-2 Hydrogen-3 1 H 2 H 3 H 1 1 1

BOHR MODELS OF HYDROGEN P P P N N N N N P N Hydrogen-1 Hydrogen-2 Hydrogen-3 1 H 2 H 3 H 1 1 1 Atomic Number (number of protons); found on the periodic chart

BOHR MODELS OF HYDROGEN P P P N N N N N P N Hydrogen-1 Hydrogen-2 Hydrogen-3 1 H 2 H 3 H 1 1 1 Atomic Number (number of protons) Mass number (sum of protons and neutrons); Not found on periodic chart

BOHR MODELS OF HYDROGEN P P P N N N N N P N Hydrogen-1 Hydrogen-2 Hydrogen-3 1 H 2 H 3 H 1 1 1 Atomic Number (number of protons) Mass number (sum of protons and neutrons); Oxidation number (Protons – electrons) Not found on periodic chart

Atomic Symbols We can distinguish isotopes with the following notation: Where: E is the atom’s symbol A is the mass number Z is the atomic number E Z A e.g. 612C, 613C, 614C, 11H, 12H and 13H As all atoms with a given symbol have the same atomic number sometimes we skip writing Z. e.g. 612C (carbon-12), 613C (carbon-13) and 614C (carbon-14)

Relative Atomic Mass If we assign a mass of 12 atomic mass units (u or sometimes amu) to a carbon-12 atom then we can compute the relative atomic weight for any other atom. Atomic weights or atomic masses are given in your periodic table.

Relative Atomic Mass Some atoms naturally occur as a mixture of isotopes. e.g. 11H, 12H and 13H The atomic weights given in the periodic table take this into account. They are the average atomic weight taking into account the amounts of each isotope present.

Relative Atomic Mass of Hydrogen When computing the average atomic mass of any element the radioactive (unstable) isotopes are excluded since there relative abundances are slowly decreasing. Hydrogen has three isotopes. The first two protium and deuterium are stable isotopes and the third tritium is unstable, thus excluded in the calculation. The relative abundance of isotopes of a particular element is constant here on our planet Earth. Mass spectroscopy gives information of relative abundances and relative masses of isotopes.

Relative Atomic Mass of Hydrogen Mass spectroscopy gives the following information for the two stable isotopes of hydrogen. isotope name relative abundance Mass (amu) Hydrogen-1 (protium) 99.985 % 1.007825 Hydrogen-2 (deuterium) 2.01355 0.015 % To calculate a weighted average, convert the percent to a decimal by moving the decimal two places to the left. Then multiply this number by the mass and add the two masses.

Relative Atomic Mass of Hydrogen 0.99985 X 1.007825 = 1.007673 0.0015 X 2.01355 = 0.003021 1.010694 amu 1.0107 amu

Relative Atomic Mass we defined the relative atomic weight of each kind of atom as follows: “assign a mass of 12 atomic mass units to a carbon-12 atom then compute the relative atomic weight for all other atom types.” Atomic mass units are very small. 1 amu = 1.67 x 10-24 g Not very practical !!!

The Chemical Package About Packages The baker uses a package called the dozen. All dozen packages contain 12 objects. The stationary store uses a package called a ream, which contains 500 sheets of paper. So what is the chemistry package? Well, it is called the mole (Latin for heap). Each of the above packages contain a number of objects that are convenient to work with, for that particular discipline.

The Mole A mole contains 6.022X1023 particles, which is the number of carbon-12 atoms that will give a mass of 12.00 grams, which is a convenient number of atoms to work with in the chemistry laboratory. The atomic weights listed on the periodic chart are the weights of a mole of atoms. For example a mole of hydrogen atoms weighs 1.00797 g and a mole of carbon atoms weighs 12.01 g.

Moles of Objects Suppose we order a mole of marshmallows for a chemistry party. How much space here at Central would be required to store the marshmallows?

Moles of Objects Suppose we order a mole of marshmallows for a chemistry party. How much space here at Central would be required to store the marshmallows? Would cover the entire 50 states 60 miles deep

Moles of Objects Suppose we order a mole of marshmallows for a chemistry party. How much space here at Central would be required to store the marshmallows? Would cover the entire 50 states 60 miles deep How about a mole of computer paper instead of a ream of computer paper, how far would that stretch?

Moles of Objects Suppose we order a mole of marshmallows for a chemistry party. How much space here at Central would be required to store the marshmallows? Would cover the entire 50 states 60 miles deep How about a mole of computer paper instead of a ream of computer paper, how far would that stretch? Way past the planet Pluto!

Formula Weight Calculation To calculate the molar mass of a compound we sum together the atomic weights of the atoms that make up the formula of the compound. This is called the formula weight (MW, M). Formula weights are the sum of atomic weights of atoms making up the formula. The following outlines how to find the formula weight of water symbol weight number H 1.01 X 2 = 2.02 O 16.0 X 1 = 16.0 18.0 g/mole

Percent Composition Find the formula weight and the percent composition of glucose (C6H12O6) symbol weight number 72.0 C 12.0 x 6 = H 1.01 x 12 = 12.12 O 16.0 x 6 = 96.0 180.1 g/mole 72.0 %C = X = 40.0 %C 180.1 12.12 %H = X = 6.73 %H 180.1 96.0 X = 53.3 %O %O = 180.1

Percent Conversions Seawater contains approximately 3.5% NaCl by mass and has a density of 1.02 g/mL. What volume of seawater would be required to produce 1.0 g of NaCl when evaporated?

Percent Conversions Seawater contains approximately 3.5% NaCl by mass and has a density of 1.02 g/mL. What volume of seawater would be required to produce 1.0 g of NaCl when evaporated? mL seawater 1.02 g seawater

Percent Conversions Seawater contains approximately 3.5% NaCl by mass and has a density of 1.02 g/mL. What volume of seawater would be required to produce 1.0 g of NaCl when evaporated? mL seawater 100 g seawater 1.02 g seawater 3.5 g NaCl

Percent Conversions Seawater contains approximately 3.5% NaCl by mass and has a density of 1.02 g/mL. What volume of seawater would be required to produce 1.0 g of NaCl when evaporated? mL seawater 100 g seawater 1.00 g NaCl 1.02 g seawater 3.5 g NaCl

Percent Conversions Seawater contains approximately 3.5% NaCl by mass and has a density of 1.02 g/mL. What volume of seawater would be required to produce 1.0 g of NaCl when evaporated? mL seawater 100 g seawater 1.00 g NaCl = 28 mL 1.02 g seawater 3.5 g NaCl

Mole Concepts A mole of glucose (C6H12O6) contains 6.022 X 1023 molecules of glucose. And 6 X 6.022 X 1023 atoms of C. Since a mole is 6.022 X 1023 particles then a mole of glucose must contain 6 moles of C atoms. How many moles of hydrogen atoms are contained in a mole of glucose? In 5 moles of H2SO4 how many moles of oxygen atoms is there?

Mole Concepts A mole of glucose (C6H12O6) contains 6.022 X 1023 molecules of glucose. And 6 X 6.022 X 1023 atoms of C. Since a mole is 6.022 X 1023 particles then a mole of glucose must contain 6 moles of C atoms. How many moles of hydrogen atoms are contained in a mole of glucose? 12 Moles of hydrogen. How many moles of oxygen and hydrogen are in one mole of H2O contains:

Mole Concepts A mole of glucose (C6H12O6) contains 6.022 X 1023 molecules of glucose. And 6 X 6.022 X 1023 atoms of C. Since a mole is 6.022 X 1023 particles then a mole of glucose must contain 6 moles of C atoms. How many moles of hydrogen atoms are contained in a mole of glucose? 12 Moles of hydrogen. How many moles of oxygen and hydrogen are in one mole of H2O contains: One mole of oxygen atoms Two moles of hydrogen atoms

Mole Concepts A mole of glucose (C6H12O6) contains 6.022 X 1023 molecules of glucose. And 6 X 6.022 X 1023 atoms of C. Since a mole is 6.022 X 1023 particles then a mole of glucose must contain 6 moles of C atoms. How many moles of hydrogen atoms are contained in a mole of glucose? 12 Moles of hydrogen. How many moles of oxygen and hydrogen are in one mole of H2O contains: One mole of oxygen atoms Two moles of hydrogen atoms In 5 moles of H2SO4 how many moles of oxygen atoms are there?

Mole Concepts A mole of glucose (C6H12O6) contains 6.022 X 1023 molecules of glucose. And 6 X 6.022 X 1023 atoms of C. Since a mole is 6.022 X 1023 particles then a mole of glucose must contain 6 moles of C atoms. How many moles of hydrogen atoms are contained in a mole of glucose? 12 Moles of hydrogen. How many moles of oxygen and hydrogen are in one mole of H2O contains: One mole of oxygen atoms Two moles of hydrogen atoms In 5 moles of H2SO4 how many moles of oxygen atoms is there? 20 moles of O atoms.

Mole Conversions In 50.0g of H2SO4 how many moles of sulfuric acid are there? 50.0g of H2SO4

Mole Conversions In 50.0g of H2SO4 how many moles of sulfuric acid are there? 50.0g of H2SO4 mole H2SO4 = 98.0g of H2SO4

Mole Conversions In 50.0g of H2SO4 how many moles of sulfuric acid are there? 50.0g of H2SO4 mole H2SO4 = 0.510 mole H2SO4 98.0g of H2SO4

Mole Conversions In 50.0g of H2SO4 how many moles of oxygen atoms are there?

Mole Conversions In 50.0g of H2SO4 how many moles of oxygen atoms are there? 50.0g of H2SO4 =

Mole Conversions In 50.0g of H2SO4 how many moles of oxygen atoms are there? 50.0g of H2SO4 mole H2SO4 = 98.0g of H2SO4

Mole Conversions In 50.0g of H2SO4 how many moles of oxygen atoms are there? 50.0g of H2SO4 mole H2SO4 4mole O = mole H2SO4 98.0g of H2SO4

Mole Conversions In 50.0g of H2SO4 how many moles of oxygen atoms are there? 50.0g of H2SO4 mole H2SO4 4mole O = 2.04 mole O mole H2SO4 98.0g of H2SO4

Mole Conversions In 5 moles of H2SO4 how many atoms of oxygen are present?

Mole Conversions In 5 moles of H2SO4 how many atoms of oxygen are present? 5 moles H2SO4 =

Mole Conversions In 5 moles of H2SO4 how many atoms of oxygen are present? 5 moles H2SO4 4 mole O mole H2SO4

Mole Conversions In 5 moles of H2SO4 how many atoms of oxygen are present? 5 moles H2SO4 4 mole O 6.02 x 1023 atoms O = mole H2SO4 mole O 1.20 x 1025 atoms

The End