matter, the atom, and the spaces...

Matter Notes- Science 8

Daintrey’s Doings J 1

Matter, the Atom, and the Spaces between! Hold on to your socks, this unit is gonna rock your world! 1. Mass, Volume and Matter Everything in this world and beyond, including your grade 8 body is made up of matter. Matter is anything that has both mass and volume. a. Mass is the amount of matter that an object contains. The more matter the greater the mass. For example Mrs Daintrey’s pug has less mass than a bull mastiff! Mass is usually weighed in grams (g) or kilograms (kg). b. Volume is the amount of space taken up by the object or substance. It is measured in milliliters (mL), liters (L) or cubic centimeters (cm3). A basketball takes up more volume than a bowling ball, but a bowling ball has more mass. c. Three states of matter: Solid Liquid Gas Shape Definite shape Takes shape of the

container it is held in Determined by surroundings

Volume Definite volume Definite Volume Determined by its surroundings

Particle movement Vibrate Slide past one another

Wizz around until they hit something and ‘bounce’ back the other direction

Kinetic Energy Low Medium High Amount of Space between particles

Little Enough to slide past A lot

Examples Bowling ball, fork, rock, ice cube

Water in a lake, juice in a glass, rain drops

Air in the atmosphere, compressed helium in a tank



B. The Particle Model of Matter: 1. All matter is made up of tiny particles (too small to see even with a microscope) 2. There is space between the particles, which contains NOTHING. 3. The particles that make up matter are always moving 4. The particles are attracted to one another C. The Kinetic Molecular Theory: According to the kinetic molecular theory, all matter is made up of very small particle that are constantly moving. Kinetic energy is the energy of motion



D. Thermal Expansion and Contraction: As you add heat to a solid, liquid or gas the temperature goes up and its particles move around faster. The particle move over more space, this increases the space between the particles. The material made up of the particles takes up more room and expands. 1. Thermal expansion:

• When you add energy to a material you increase the kinetic energy (energy of motion)

• The most common way to increase energy is to heat a substance • Most materials expand, or increase their volume when they are

heated. This is called THERMAL EXPANSION. The opposite is also true…



2. Thermal contraction:

• When temperature decreases, the particle slow down and have less space between them. The material decreases in volume or shrinks, or goes through THERMAL CONTRACTION.

• Different materials expand and contract at their own rate.

Why does a hot drinking glass shatter when it is placed in cold water? E. Are Heat and Temperature the Same?

• Nope! THERMAL ENERGY is the total amount of kinetic energy of the particle in a substance or object.

• TEMPERATURE is the average kinetic energy of a substance or object.

• HEAT is the energy transferred from one material or object to

another as a result of a difference in temperature.

• As heat is added, the temperature goes up.



• Think about when you hold a cup of hot chocolate on a cold day. Or when you are holding onto your mom’s hand. Too old for that? Energy always travels from an area of high energy to low energy.

What has more heat: an iceberg or a cup of hot

water? Which has a higher temperature?

F. Changes of State:

As the space between the particles changes so does the state of matter.

• Melting – Change of state from a solid to liquid • Evaporation – Change of state from a liquid to gas • Condensation – Change of state from a gas to liquid • Solidification – Change of state from a liquid to solid • Sublimation – Change of state directly from a solid to gas • Deposition – Change of state from gas to solid • All substances have different specific temperatures at which they

change states. • Melting point – Temperature at which a solid turns to a liquid. • Boiling point – Temperature at which a liquid turns to a gas

SOLID

LIQUID GAS



G. Density: Which one are we talking about? 1.the state or quality of being dense; compactness; closely set or crowded condition. 2. stupidity; slow-wittedness; obtuseness. 3. the number of inhabitants, dwellings, or the like, per unit area: The commissioner noted that the population density of certain city blocks had fallen dramatically. 4. Physics. mass per unit volume. Measured in g/mL or g/cm3

Sample Questions: 1. Oil floats on water. The most accurate reason for this is

a) oil is less dense than water b) oil is immiscible (does not dissolve) in water c) oil is both less dense and immiscible with water d) water is heavier than oil

2. A block of wood 3 cm on each side has a mass of 27 g. What is the density of the block? (Hint, don’t forget to find the volume of the wood.)



H. Viscosity, Adhesion, and Cohesion

Term Definition Viscosity Is the resistance of a fluid to flow. The slower the

fluid the greater the viscosity

Adhesion The attraction between the molecules of two different substances in contact with each other

Cohesion The strength with which the particles of an object or fluid are attracted to each other

Flow Rate The speed at which a fluid flows from one point to another

Surface Tension A property of a liquid in which molecules at the surface of the liquid attract each other, causing the surface to act like a thick skin or membrane

i: The Effect of Particle Shape on Viscosity Looking at the shape of the water and oil molecules, which one will flow and have a lower viscosity?

When oil flows the complicated shape make it more difficult for the molecules to flow past each other.

ii: The Effect of Temperature on Viscosity:

• Heating a substance will decrease the viscosity and cooling a liquid will increase its’ viscosity



iii: Adhesion & Cohesion

• Remember that Adhesion is the attraction of two different objects or fluids to each other.

o Think of the last few drops of water in a glass

• Cohesion is the strength with which particles of an object or fluid attract each other.

o Water droplets on leafs or on spider webs

• Water droplets are attracted to one another at waters surface, causing the surface of the liquid to act as a thin skin or membrane.

• We call this surface tension.

• Objects with larger densities can stay at the surface of the

water. Which fluid is the least viscous?



2. The Classification of Matter: Matter is anything that has mass and volume. It can be classified into pure substances and mixtures. A. Pure Substance: à is matter that contains only one type or particle i. Element: à is a pure substance that cannot be changed into anything simpler. ii. Compound à is a pure substance that consists of two or more elements

B. Mixtures: à mixtures are two or more pure substances mixed together.

i. Heterogeneous Mixture: à is a mixture that is not uniform in it’s composition, you can see the

different components in it.

ii. Homogeneous Mixture à is made of substances that are evenly and microscopically

mixed together. You cannot see the different components.



C. Changes in Matter Knowing the Difference

Physical Change Chemical Change

1. Able to Reverse 1. Not able to reverse 2. No new substance formed 2. New substance formed 3. Properties don’t change 3. New properties form 4. Energy change may occur, but may not be noticed

4. Energy change may occur

Examples Examples When cream is whipped, air puffs up the cream. The substances are still cream and air

Baking powder reacts when heated to create carbon dioxide, which makes bread rise. All baking is considered to be a chemical reaction

Boiling, Freezing, and Sublimation of water Gasoline burns slowly creating energy Sugar dissolves in tea. It seems to disappear, but you can get it back by b

Sunlight causes the body to create vitamin D and melanin in the skin

Tattooing Coloring your hair

3. The Atomic Theory:

A. The Atomic Theory of Matter 1. All matter is made of atoms 2. Atoms are the smallest pieces of an element 3. Elements combine to form compounds. The atoms in the compound are

held together by electrical attractions 4. An atom is composed of a nucleus surrounded by electrons 5. The nucleus contains most of the mass of the atom and all of the

positive charge



6. There is only empty space between the electrons and nucleus 7. Electrons have a negative charge and almost no mass 8. Electrons float around the nucleus in specific shells 9. For the 1st 20 elements the second shell contains an max of 8

electrons, and the 3rd shell contains a max of 8 electrons 10. Electrons absorb or emit specific amounts of energy to change shells

B. Naming and Classifying the Elements Symbols

à Every element is represented by the 1st letter of its name or by the 1st and 2nd letter from it’s name. à For elements that were discovered a long time ago, this was from their latin name. à When one letter has been used (carbon = C) they add letters on to differentiate (Cobalt = Co) à The first letter is always a capital and the second is always lower case C. The Subatomic Particles:

Subatomic Particle Charge Mass Location Protons Positive Has mass Nucleus

Neutrons Neutral Has mass Nucleus

Electrons Negative Virtually no mass Orbits around the nucleus



D. Mendeleve and the Periodic Table Putting the Elements in Order A. Ordering by Properties

à Dmitri Mendeleev, created the periodic table in the mid 1800s. à He ordered the elements by properties and by increasing mass, from left to right.

B. Predicting with Properties: à Based on groups and masses, chemists can predict properties of some of the elements, like boiling and melting point àPointing the way to the Future à Mendeleev’s table wasn’t complete or perfect, but it helped point us in the correct direction for making the modern periodic table.

C. Atomic Notation à When you see a square on the periodic table there are a few things that you need to be aware of:

a. Atomic number = The number protons in the nucleus b. Mass number = total number of protons and neutrons in the

nucleus



E. The Periodic Table: 1. Finding Information on the Periodic Table

13 2.70 3+ Al Aluminum 26.98

i. Atomic Number (13) = tells you the number of protons in the nucleus ii. Charge = the most common ion charge when the element is charged iii. Symbol = Short for from the element iv. Atomic Mass = is the average mass of the element. To calculate the

number of neutrons in an element you round the atomic mass number to the nearest whole number and subtract the atomic number from it.

Let’s calculate Protons, Neutrons and Electrons for Aluminum:

Protons Neutrons Electrons in Atom Electrons in an Ion

2. Calculating Electron Numbers:

i. In a neutral atom, the number of electrons is equal to the number of protons, which is the atomic number. This means if you do not see at + or a -, the atomic number is = to the number of electrons

Element Atomic Number Electrons Al

C

O

As

F



E. Quarks and Leptons A quark (/ˈkwɔrk/ or /ˈkwɑrk/) is an elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei

Leptons are said to be elementary particles; that is, they do not appear to be made up of smaller units of matter. Leptons can either carry one unit of electric charge or be neutral. The charged leptons can become the electrons

matter, the atom, and the spaces...

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