Unit 1 Properties off Matter Mrs. Ayyad

Chapter Summary: Key Points 1 The Scientific Method States of Matter Substances Mixtures Physical Properties Chemical Properties Extensive and Intensive Properties SI Base Units Mass Temperature Volume and Density Significant Figures

How Matter is Classified? Atoms: the smallest unit of an element that maintains the properties of that element. Elements: are pure substances that contain one kind of atom. Molecule : consists of two or more atoms combined in definite ratios. Compound: 2 or more atoms that are different combined together. https://www.youtube.com/watch?v=0gsrW0Vb5sw

Atomic Structure There are two basic components in every atom: Electron Cloud Nucleus

Subatomic Particles Three subatomic particles make up every atom: Charge Location Proton Positive (+) Nucleus or “Core” Neutron No Charge (0) Electron Negative (-) Electron Cloud

What's an Element?

How to write an Element

C Mass # Atomic # Isotopes Atoms of the same element with different mass numbers. Nuclear symbol: 12 6 C Mass # Each isotope has a different number of neutrons. Atomic # Hyphen notation: carbon-12 Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Cl Isotopes 37 17 Cl Chlorine-37 atomic #: 17 mass #: 37 # of protons: # of electrons: # of neutrons: 17 37 20 37 17 Cl Atoms that have the same number of protons, and hence the same atomic number, but different numbers of neutrons are called isotopes. Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Average Atomic Mass Avg. (mass)(%) + (mass)(%) Atomic Mass 100 weighted average of all isotopes on the Periodic Table round to 2 decimal places Avg. Atomic Mass (mass)(%) + (mass)(%) = 100 Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Average Atomic Mass Avg. Atomic 16.00 Mass amu EX: Calculate the avg. atomic mass of oxygen if its abundance in nature is 99.76% 16O, 0.04% 17O, and 0.20% 18O. Avg. Atomic Mass (16)(99.76) + (17)(0.04) + (18)(0.20) = 16.00 amu = 100 Amu- Atomic mass unit Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Answer Worksheet

Classification of Matter A mixture can be separated by physical means into its components without changing the identities of the components.

Classification of Matter Gases assume both the shape and volume of their container. Solids do not conform to the shape of their container. Liquids do conform to the shape of their container. Solid particles are held closely together in an ordered fashion. Liquid particles are close together but are not held rigidly in position. Gas particles have significant separation from each other and move freely.

Three states of matter gas solid liquid At room temperature most substances exist in one of three physical states. solid liquid gas

Solids The particles in a solid are very tightly packed and vibrate in place. Solids have a definite volume and shape.

Particles in a solid – animation

Liquids The particles in a liquid are close together but can move and flow past one another. Liquids have a definite volume but they do not have a definite shape. This is why liquids like water take the shape of the container they are in. Picture was taken at the exact moment these water balloons were popped!

Particles in a liquid – animation

Gases Particles in a gas have higher amounts of energy than those in a solid or liquid. Gases do not have a definite shape or volume. When placed in a container, it fills up the entire container and spreads out as far as possible.

Particles in a gas – animation

Molecular Motion Adding heat Removing heat

The Properties of Matter There are two general types of properties of matter: 1) Quantitative properties are measured and expressed with a number. 2) Qualitative properties do not require measurement and are usually based on observation.

The Properties of Matter A physical property is one that can be observed and measured without changing the identity of the substance. Examples: color, melting point, boiling point A physical change is one in which the state of matter changes, but the identity of the matter does not change. Examples: changes of state (melting, freezing, condensation)

The Properties of Matter A chemical property is one a substance exhibits as it interacts with another substance. Examples: flammability, corrosiveness A chemical change is one that results in a change of composition; the original substances no longer exist. Examples: digestion, combustion, oxidation

The Properties of Matter An Extensive property depends on the amount of matter. Examples: mass, volume An Intensive property does not depend on the amount of matter. Examples: temperature, density

Temperature There are two temperature scales used in chemistry: The Celsius scale (°C) Freezing point (pure water): 0°C Boiling point (pure water): 100°C The Kelvin scale (K) The “absolute” scale Lowest possible temperature: 0 K (absolute zero) K = °C + 273

Temp in °F = ( ×temp in °C ) + 32°F Temperature The Fahrenheit scale is common in the United States. Freezing point (pure water): 32°C Boiling point (pure water): 212°C There are 180 degrees between freezing and boiling in Fahrenheit (212°F-32°F) but only 100 degrees in Celsius (100°C-0°C). The size of a degree on the Fahrenheit scale is only of a degree on the Celsius scale. Temp in °F = ( ×temp in °C ) + 32°F

Density Typicall the units are g/ mL or g/ cm3 mass density = m volume A piece of platinum metal with a density of 21.5 g/cm3 has a volume of 4.49 cm3. What is its mass? d = m V m = d x V = 21.5 g/cm3 x 4.49 cm3 = 96.5 g Taylor 2010

Density A piece of metal with a mass of 114 g was placed into a graduated cylinder that contained 25.00 mL of water, raising the water level to 42.50 mL. What is the density of the metal? Ans: D 0.154 g/mL 0.592 g/mL 2.68 g/mL 6.51 g/mL 7.25 g/mL Taylor 2010

Accuracy and Precision Good accuracy and good precision Accuracy tells us how close a measurement is to the true value. Precision tells us how close a series of replicate measurements are to one another. Poor accuracy but good precision Poor accuracy and poor precision

Day 2 Scientist

Democritus (460 BC – 370 BC) Proposed an Atomic Theory (along with his mentor Leucippus) which states that all atoms are small, hard, indivisible and indestructible particles made of a single material formed into different shapes and sizes. Aristotle did not support his atomic theory Image taken from: https://reich-chemistry.wikispaces.com/T.+Glenn+Time+Line+Project

Image taken from: www.ldeo.columbia.edu/.../v1001/geotime2.html Antoine Lavoisier (1743 – 1794) Known as the “Father of Modern Chemistry” Was the first person to generate a list of thirty-three elements in his textbook Devised the metric system Was married to a 13-year old Marie-Anne Pierette Paulze; she assisted him with much of his work Was a tax-collector that was consequently guillotined during the French Revolution Discovered/proposed that combustion occurs when oxygen combines with other elements Discovered/proposed the Law of Conservation of Mass (or Matter) which states, in a chemical reaction, matter is neither created nor destroyed Image taken from: www.ldeo.columbia.edu/.../v1001/geotime2.html

Image taken from: chemistry.about.com/.../John-Dalton.htm In 1803, proposed an Atomic Theory which states: All substances are made of atoms; atoms are small particles that cannot be created, divided, or destroyed. Atoms of the same element are exactly alike, and atoms of different elements are different Atoms join with other atoms to make new substances Calculated the atomic weights of many various elements Was a teacher at a very young age Was color blind Image taken from: chemistry.about.com/.../John-Dalton.htm

Atomic Theory Timeline Scientist Information Model John Dalton All matter is made of atoms. Atoms are too small to see, indivisible and indestructible. All atoms of a given element are identical.

Image taken from: www.wired.com/.../news/2008/04/dayintech_0430 J.J. Thomson (1856 – 1940) Proved that an atom can be divided into smaller parts While experimenting with cathode- ray tubes, discovered corpuscles, which were later called electrons Stated that the atom is neutral In 1897, proposed the Plum Pudding Model which states that atoms mostly consist of positively charged material with negatively charged particles (electrons) located throughout the positive material Won a Nobel Prize Image taken from: www.wired.com/.../news/2008/04/dayintech_0430

Atomic Theory Timeline Scientist Information Model J.J Thompson Discovered the negative electron, and predicted that there also must be a positive particle to hold the electrons in place.

Atomic Theory Timeline Scientist Information Model Ernest Rutherford Discovered the nucleus of an atom and named the positive particles in the nucleus “protons”. Concluded that electrons are scattered in empty space around the nucleus.

Atomic Theory Timeline Neutrons Scientist Information Model James Chadwick Discovered that neutrons were also located in the nucleus of an atoms and that they contain no charge.

Atomic Theory Timeline Scientist Information Model Neils Bohr Concluded that electrons are located in planet-like orbits around the nucleus in certain energy levels.

http://www.brainpop.com/science/matterandchemistry/atomicmodel/ Additional video resource: http://studyjams.scholastic.com/studyjams/jams/science/matter/solids-liquids-gases.htm

The Law of Conservation of Mass

We’ve talked about changes in matter… The evaporation of a puddle of water Rust forming on a metal fence PHYSICAL CHEMICAL

The Law of Conservation of Mass During a chemical reaction, matter cannot be created or destroyed. Even though the matter may change from one form to another, the same number of atoms exists before and after the change takes place!

Open System There is exchange of matter and energy with surroundings Mass is lost to the environment; once gone, that mass cannot be measured. Example: Burning Wood

Closed System No matter can enter/leave the system only energy

An Example of the Closed System. Test tube containing lead nitrate is placed upright in a flask that contains potassium iodide. What are these? REACTANTS! They don’t mix!

A stopper is put in place to create a closed system – an environment where matter cannot enter or escape. The mass of the system is found.

After the mass is found, the system is turned upside down so the lead nitrate can mix with the potassium iodide. They create lead iodide and potassium nitrate.

Although the matter changed in form, the total mass of the system remains unchanged.

When iron reacts with oxygen in the air, they form rust or IRON OXIDE. This is written as: Iron + Oxygen Iron Oxide

TAKE A LOOK AT THE NUMBERS REACTANTS PRODUCT O2 Fe2O3 Fe Fe O2 O2 What about the PRODUCT? How many Oxygen molecules? How many Iron molecules?

Independent Variable – something that is changed by the scientist 3 Kinds of Variables Independent Variable – something that is changed by the scientist What is tested What is manipulated

Variables https://www.youtube.com/watch?v=x2606GQmDqY