Net
Force-
the force that results from combining all the forces exerted on an object. Same
direction ADD. Different direction find the DIFFERENCE.
Science CST Notes
Structure of Matter- Chapters 2-4
Mass is the amount of matter in an object.
Mass and weight are not the same thing.
· Weight is a measure of the gravitational force on an object, usually in relation to the Earth.
Chapter 2:2
The density (mass per unit volume) of a substance is always the same at a given pressure and temperature regardless of the size of the sample of the substance.
Density = mass/volume or D=m/V
Buoyancy
Buoyant force on an object in a fluid is an upward force equal to the weight of the fluid the object has displaced.
Chapter 3:1
states of matter- the physical forms in which a substance can exist; states include solid, liquid, gas and plasma.
solid- the state in which matter has a definite shape and volume.
liquid- the state in which matter takes the shape of its container but has definite volume.
gas- the state in which matter changes in both shape and volume.
plasma- the state of matter that does not have a definite shape or volume and whose particles have broken apart; plasma is composed of electrons and positively charge ions. It is the most prevent state in the universe.
· The states of matter (solid, liquid, gas) depend on molecular motion.
· Solid atoms are closely locked in position and can only vibrate.
· Liquid atoms and molecules are more loosely connected and can collide with and move past one another.
· Gases atoms and molecules are free to move independently, colliding frequently.
Chapter 4-Section 1
· A substance in which all the particles are alike is a pure substance=element.
Each element has a unique set of physical and chemical properties.
Elements are classified as metals, nonmetals, and metalloids based on their properties.
Chapter 4:2
A compound is a pure substance composed of two or more elements chemically combined.
Each compound has a unique set of physical and chemical properties that are different from the properties of the elements that compose it. Example- NaCl
The elements that form a compound always combine in a specific ratio according to their masses. 2H + O θ H2O
Compounds can be broken down into simpler substances by chemical changes like electrolysis and heating.
Chapter 4:3
A mixture is a combination of two or more substances, each of which keeps its own characteristics. (Salad or Pizza)
Mixtures can be separated by physical means, such as filtration and evaporation.
A solution is a mixture that appears to be a single substance but is composed of a solute dissolved in a solvent.
Concentration is a measure of the amount of solute dissolved in a solvent.
· Water is the universal solvent. Solute sounds like cute- so, smaller amount added is the Solute. (Water/Salt= salt is the solute).
Motion- Chapter 5:1
Speed is the distance traveled divided by the time
S=d/t
Average speed is the total distance traveled divided by the total time
AS=total d/total t
Velocity- rate (speed/magnitude) in a specific direction
V=d/t in a specific direction
Acceleration- final velocity minus the initial (starting) velocity all divided by the time it takes to change velocity (in a given direction)
Acceleration=Vf Vs/ t
An object is in motion if it changes position over time when compared with a reference point. Reference point is the background.
Forces- Chapter 5:2-4 and Chapters 6-7
Net
Force-
the force that results from combining all the forces exerted on an object. Same
direction ADD. Different direction find the DIFFERENCE.
5
N 10 N = 15 N right
15 N 25 N = 10 N left
· Force has both direction and rate/magnitude expressed in Newtons (N). Example: 15 N right
Unbalanced forces produce a change in motion (acceleration) Ex. kick a soccer ball- Why? ball changes speed/direction.
Balanced forces produce no change in motion. (net force of zero) Ex. stalemate, draw, not being able to move a heavy object.
Chapter 12-13
Ch12:1
· Atoms are small particles that make up all matter; atoms cannot be created, divided, or destroyed;
atom- the smallest particle into which an element can be divided and still retain all of the properties of that element.
electrons- the negatively charged particle s found in all atoms; electrons are involved in the formation of chemical bonds.
nucleus- the tiny, extremely dense, positively charged region in the center of an atom; made up of protons and neutrons.
Ch12:2
A proton is a positively charged particle with a mass of 1 amu.
A neutron is a particle with no charge that has a mass of 1 amu.
An electron is a negatively charged particle with an extremely small mass (almost 0 amu).
Protons and neutrons make up the nucleus. Electrons are found in electron clouds outside the nucleus.
The number of protons in the nucleus of an atom is the atomic number.
Isotopes of an atom have the same number of protons but have different numbers of neutrons. Isotopes share most of the same chemical and physical properties.
The mass number of an atom is the sum of the atoms neutrons and protons.
The atomic mass is an average of the masses of all naturally occurring isotopes of an element.
The four forces at work in an atom are gravity, the electromagnetic force, the strong force, and the weak force.
· The atomic number shows how many protons are in the nucleus of the element. In general an element has the same number of electrons as protons. For the element hydrogen (H) the atomic number is 1. That means there is 1 proton and so there is 1 electron.
· The electrons orbit around the nucleus in different layers (shells). The closest layer to the nucleus has room for 2 electrons; the second layer has room for 8 electrons; the third layer has room for 18 and so on. There may be fewer electrons than there is room for. The rule for the number of electrons that can occupy a particular layer is two times the square of the layer number (2n²).
Adding or taking away protons from an atom creates a different element. However, in general, electrons can be added or taken away and only the charge of the element is changed.
· The atomic mass shows the total number of protons and neutrons. Use this information to find the number of protons, electrons, and neutrons in hydrogen.
Carbon (C)
Atomic number = 6 Atomic mass = 12(12.0107 rounded to the nearest whole number)
Number of protons = the atomic number There are 6 protons
Number of electrons = number of protons There are 6 electrons
Number of neutrons = mass protons
There are 12 6 = 6 neutrons
Isotopes- Atoms of the same element can have different numbers of neutrons. The different versions of each element are called isotopes. The atomic number is the same for each isotope, but the atomic mass varies. The symbol for an isotope is written as the element symbol and the number of neutrons.
The isotope of hydrogen with 2 neutrons is written ²H. The isotope of carbon with 12 neutrons is written Ή²C.
Mass of Protons, Neutrons, and Electrons
The atomic mass of the nucleus of a carbon-12 isotope (Ή²C) is 12. Scientists use one-twelfth of this mass as the atomic mass unit (amu) for measuring atomic particles. While not precisely correct, the mass of a proton and neutron are said to be 1 amu. The mass of an electron is said to be 1/1836 amu.
This table summarizes the mass and charge of protons, neutrons, and electrons.
Particle mass in amu charge
Proton 1 + 1
Neutron 10 neutral
Electron 1/1836 -1
This table gives information about carbon isotopes.
Isotope Protons Neutrons Mass in amu
Carbon-12 6 6 12
Carbon-13 6 7 13
Carbon-14 6 8 14
Matter Matter is anything that has mass and takes up space. Matter can exist as a solid, liquid, or gas. The form of matter may change. For example, water becomes solid below freezing, and lead can be heated to a liquid.
All matter is made up of atoms. The weight of matter is a measure of the force that gravity places on its mass. Matter is conserved. That is, it cannot be created or destroyed, but it can be converted into energy.
Compound
A compound is formed when two or more elements unite chemically. A molecule is the smallest part of a compound with the properties of that compound.
There are three important types of chemical compounds acids, bases, and salt. Acids dissolved in water produce hydrogen. Bases dissolved in water produce hydroxide. When acids and bases are combined chemically, they form salt.
Solution
A solution is formed when element(s) or compound(s) are dissolved in another substance. Club soda is a solution with carbon dioxide dissolved in water. Lemonade is a solution of lemon juice and sugar dissolved in water.
Chemical reaction
A chemical reaction is when one or more new substances are formed. A chemical reaction involves the rearrangement of electrons. One example of a chemical reaction is when concrete is created from mixing water and cement. Chemical reactions also occur when elements are heated, cooled, and burned.
Chapter 13:1
A horizontal row of elements is called a period. The elements gradually change from metallic to nonmetallic from left to right across each period.
A vertical column of elements is called a group or family. Elements in a group usually have similar properties.
Elements in the periodic table are divided into metals, metalloids, and nonmetals.
· Groups have similar chemical and physical properties.
1. Currently we arrange the elements in order of increasing atomic number.
2. Elements in the periodic table are divided into metals, metalloids, and nonmetals.
3. A horizontal row of elements is called a period.
4. A vertical column of elements is called a group or family. Elements in families usually have similar properties.
5. The alkali metals (Group 1) are the most reactive metals.
6. The alkaline-earth metals (Group 2) are less reactive than the alkali metals.
7. The transition metals (Groups 312) include most of the well-known metals as well as the lanthanides and actinides located below the periodic table.
8. The halogens (Group 17) are very reactive nonmetals.
9. The noble gases (Group 18) are unreactive nonmetals. These elements have a complete set of electrons in their outer level.
10. Hydrogen is set off by itself because its properties do not match the properties of anyone group.
Chapter 13 Questions
11. Currently we arrange the elements in order of increasing atomic number.
12. Elements in the periodic table are divided into metals, metalloids, and nonmetals.
13. A horizontal row of elements is called a period.
14. A vertical column of elements is called a group or family. Elements in families usually have similar properties.
15. The alkali metals (Group 1) are the most reactive metals.
16. The alkaline-earth metals (Group 2) are less reactive than the alkali metals.
17. The transition metals (Groups 312) include most of the well-known metals as well as the lanthanides and actinides located below the periodic table.
18. The halogens (Group 17) are very reactive nonmetals.
19. The noble gases (Group 18) are unreactive nonmetals. These elements have a complete set of electrons in their outer level.
20. Hydrogen is set off by itself because its properties do not match the properties of anyone group.
Chapter 14-16 Reactions
Chapter 14:1
· We can use the Group in the Periodic Table to help us predict the number of valence electrons in an element?
· Chemical bonding is the joining of atoms to form new substances. New substances have DIFFERENT properties than original elements. (NaCl)
· Valence electrons are the electrons in the outermost energy level of an atom. These electrons are used to form bonds.
Most atoms form bonds by gaining, losing, or sharing electrons until they have 8 valence electrons. Atoms of hydrogen, lithium, and helium need only 2 electrons to fill their outermost level.
Chapter 15:1
· Chemical reactions form new substances with different properties than the starting substances.
· Clues that a chemical reaction is taking place include formation of a gas or solid, a color change, and an energy change.
· Law of Conservation of Mass-mass will NOT increase or decrease in a chemical reaction.
Chapter 16:2
PROPERTIES OF ACIDS
· Corrosive ('burns' your skin)
· Sour taste (e.g. lemons, vinegar)
· Can change the color of certain compounds
· Has a pH of less than 7
· Examples of acids: fruit, vinegar, soda, tea
PROPERTIES OF BASES
· Corrosive ('burns' your skin)
· Soapy feel
· Tastes bitter
· Has a pH more than 7
· Examples of Bases: detergent, soap, bleach, ammonia, toothpaste.
· When combined, an acid and a base neutralize one another to produce water and a salt.
· A salt is an ionic compound formed from the positive ion of a base and the negative ion of an acid.
Chapter 16:3- Carbon is Cing
· Carbon, because of its ability to combine in many ways with itself and other elements, has a central role in the chemistry of living organisms.
· Carbon is found in abundance in the sun, stars, comets, and atmospheres of most planets.
· Carbon is the fourth most abundant element in the known universe.
· Common carbon compounds in the environment include the gases carbon dioxide (CO2) and methane (CH4).
· Living organisms are made of molecules consisting largely of carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.
· Carbon bonds in many ways with itself to form chains, which is why carbon it essential to living organisms.
· Carbon is best able to combine with itself and hydrogen (H) to form large molecules.
· Compounds containing carbon are is most likely to be part of living organisms. Example: C6H12O6
Chapter 17-19 Earth in the Solar System (Earth Sciences)
17:1 A Solar System is Born
The solar system is A sun=star, planets in orbit around sun. p424
Planets move faster in their orbits when they are closer to the sun.
Gravity depends on the masses of the interacting objects and the distance between them. P424-5
Does sun and star mean the same thing? yes
17:2 The Sun
The sun is a gaseous sphere made primarily of hydrogen and helium.
The sun produces energy in its core by a process called nuclear fusion.
18:1 The Nine Planets
The solar system has nine planets.
Planets and their moons shine because they reflect sunlight. p453
Distances within the solar system can be expressed in astronomical units (AU) or in
light-minutes. An example would be the distance between the Sun and Earth-1.00 AU/1.5 x 108 km/8.3 light minutes.
The inner four planets, called the terrestrial planets, are small, dense and rocky. These planets are Mars, Earth, Venus, and Mercury.
The outer planets, with the exception of Pluto, are gas giants (Very large and are made of mostly gases). These planets are Jupiter, Saturn, Uranus, and Neptune.
18:2 The Moon
The moons phases are caused by the moons orbit around the Earth. At different times of the month, we view different amounts of sunlight on the moon because of the moons position relative to the sun and the Earth.
Lunar eclipses occur when the Earths shadow falls on the moon.
Solar eclipses occur when the moon is between the sun and the Earth, causing the moons shadow to fall on the Earth.
18:3 Comets, Asteroids, and Meteoroids
Comets are small bodies of rock, ice, and cosmic dust left over from the formation of the solar system. (dirty snowballs)
Asteroids are small, rocky bodies that orbit the sun between the orbits of Mars and Jupiter.
Meteoroids are very small, rocky bodies that probably come from asteroids.
19:1 Stars
The color of a star depends on its temperature. Hot stars are blue. Cool stars are red.
The spectra of stars indicate their composition. Spectra are also used to classify stars.
The magnitude of a star is a measure of its brightness.
Apparent magnitude is how bright a star appears from Earth.
Light year is the distance light travels in a year. It is used to measure the distance between galaxies.
19:2 The Life Cycle of Stars
New stars form from the material of old stars that have gone through their life cycles.
The H-R diagram relates the temperature and brightness of a star. It also illustrates the life cycle of stars.
Most stars are main-sequence stars. Red giants and white dwarfs are later stages in a stars life cycle.
Massive stars become supernovas. Their cores turn into neutron stars or black holes.
19:3 Galaxies
Galaxies are made up of billions of stars.
Galaxies are classified according to their size and shape. Major types include spiral, elliptical, and irregular galaxies.
Spiral galaxies have a bulge in the center with spiral arms branching out. Spiral is also the most common galaxy.
Elliptical galaxies contain a bright center with very little dust or gas. Many contain old stars and may form a cucumber shape.
Irregular galaxies have an irregular shape.
The Milky Way is our galaxy.
A nebula is a cloud of gas and dust. New stars are born in some nebulas.
Investigation and Experimentation
y= mx + b
Determine a missing quantity in a mathematic expression, given the two remaining terms.
Force = pressure Χ area
Volume = area Χ height
Distinguish between linear and nonlinear relationships on a graph of data.
Last Update: 04/27/2010 05:52 PM -0500