Term
| What happens to reactants during chemical reaction? |
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Definition
| The atoms and moecules of the reactant (original substances) rearrange during a chemical reactinon. |
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Term
| What are examples of physical change? |
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Definition
| Physical changes are NOT chemical reactions. Examples uncluded freezing, melting, boiling, evaporating, and condensing. |
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Term
| What is the difference between products and original substances? |
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Definition
| The products (new substances) have different properties than the orignial substances. |
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Term
| How are physical changes different from chemical reactions? |
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Definition
| Physical changes only change the form or appearance but NOT create new substances. |
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Term
| What does the Law of Conservation of Matter say? |
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Definition
| The Law of Conservation of Matter states that atoms are never created or destroyed. This means that atoms can only be rearranged not added or subtracted during a reaction. |
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Term
| Are mixtures & solutions chemical reactions? Explain? |
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Definition
| Mixtures and solutions are NOT chemical reactions because new substances are not formed |
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Term
| What does a chemical equation show? |
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Definition
| A chemical equation shows what happens during a reaction. There are always the same kinds of and numbers of atoms on both sides of the equation. |
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Term
| What are the pH levels of acidic solutions? What do greater #'s mean? |
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Definition
| A solution with a pH of 0-6 is acidic. Acids are sour and react with metals to make hydrogen gas. The greater the number, the less acidic a solution is. (A pH of 7 is neutral. Water is neutral.) |
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Term
| What happens to energy during reactions? |
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Definition
| Most reactions either absorb heat energy or release heat energy. |
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Term
| What are pH levels of basic solutions? What do greater #'s mean? |
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Definition
| A solution with a pH of 8-14 is basic. Bases are bitter, slippery, and can conduct electricity. The greater the number, the more basic a solution is. |
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Term
| What is the structure of the atom? |
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Definition
| The atom is made of a core of protons and neutrons surrounded by electrons. |
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Term
| What are the parts of an atom? |
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Definition
| The atoms has protons with a positive charge, neutrons with a neutral charge, and much smaller electrons with a negative charge |
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Term
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Definition
| There are about 100 different types of matter, each with their own properties and atomic structure, called elements. |
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Term
| Describe the molecules in a solid |
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Definition
| The molecules in a solid are locked in position and can only vibrate |
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Term
| Describe the molecules in a liquid. |
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Definition
| The molecules in a liquid are loosely connected and can move past one another and may collide with one another. |
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Term
| Describe the molecules in a gas. |
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Definition
| The molecules in a gas are free to move, they mover very quickly and collide frequently |
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Term
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Definition
| Compounds are formed by chemically combining 2 or more different elements. Compounds have different properties from the elements that make them. |
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Term
| What is the center of an atom? |
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Definition
| The center of the atom is the nucleus made of protons and neutrons. Most of the mass of the atom is in the nucleus |
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Term
| What forms the outside of the atom? |
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Definition
| The outside of the atom is the electron cloud made of spinning very lightweight electrons |
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Term
| How do atoms and molecules form special solids? |
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Definition
| Atoms and molecules form some solids by building up repeating patterns like those found in crystalline solids and long-chain polymers. |
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Term
| Describe characteristics of metals |
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Definition
| Metals are good conductors of heat and electricity and have higher melting points |
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Term
| Describe characteristics of non-metals |
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Definition
| Non-metals are not good conductors of heat and electricity and have lower melting points. |
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Term
| Describe characteristics of noble (inert) gasses. |
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Definition
| Noble (or inert) gasses do not combine easily with other elements. |
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Term
| Where are metals and non-metals found on the periodic table? |
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Definition
| Metals are found on the left of the zig-zag line. Non-metals are found on the right of the zig-zag line. |
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Term
| Where are noble (or inert) gasses found on the periodic table? |
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Definition
| Noble gasses are found in the far right column of the periodic table. |
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Term
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Definition
| Isotopes are different versions of the same element. They have the same number of protons but different number of neutrons. |
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Term
| Why is carbon important in the chemistry of living things? |
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Definition
| Because carbon is able to combine with many different elements it plays an important role in the chemistry of living things. This means that carbon is often a part of living things. |
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Term
| What types of molecules make up living things? |
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Definition
| Living things are made of very small molecules like salt and water and they are made of very large molecules like proteins, DNA, carbohydrates, and fats. |
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Term
| What can we read on a periodic table? |
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Definition
| We can find the names, symbols, and atomic numbers of all the elements on the periodic table. |
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Term
| What is an atomic number? |
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Definition
| The atomic number is the number that identifies an element on the periodic table. It is the number of protons in that element. |
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Term
| How do we describe forces? |
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Definition
| Forces have both direction and magnitude (amount of force). The direction and magnitude can be shown by arrows. |
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Term
| How do we find the cumulative (total) force? |
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Definition
| Multiple forces can act on an object. Forves moving in the same direction are added. Forces moving in opposite directions are subtracted. Movement is cause by greater forces. |
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Term
| What happens if the forces are balanced? |
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Definition
| Balanced forces are equal and opposite forces. When forces are balanced, there is no movement |
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Term
| What are different forces that can act on an object? |
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Definition
| Forces actin on an object include gravity, friction, tension, compression, and normal force. |
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Term
| What happens if forces are unbalanced? |
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Definition
| When forces are unbalanced, the object will change its velocity (speed up, slow down, or change direction). |
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Term
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Definition
| Density is mass per unit volume. |
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Term
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Definition
| A buoyant force is the upward force of a liquid on an object. It is equal to the weight of the fluid the object has displaced (moved). |
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Term
| How can we predict whether an object will float or sink? |
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Definition
| An object will sink if it has a density more than the fluid in which it is placed. It will float if the density is less than the fluid. |
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Term
| What is the density of water? What will float in water? |
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Definition
| The density of water is 1.0 grams/mL. Anything with a density less than 1.0 gr/mL will float in water. |
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Term
| How do we find the density of an object? |
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Definition
| Density = mass (grams) / volume (mL or cm^3). (Volume can be found by placing an object in a grauated cylinder of water and seeing how much water is displaced.) |
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Term
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Definition
| A galaxy is a cluster (group) of billions of stars. |
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Term
| What are the different shapes of galaxies? |
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Definition
| Some examples of the many different shapes are spiral, elliptical (oval), and irregular. |
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Term
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Definition
| Our Sun is a medium yellow star found in one of the arms of a spiral shaped galaxy called the Milky Way |
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Term
| Describe the different colors of stars. |
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Definition
| Stars have different temperatures and colors. Colors include, red (cooler stars), yellow (medium temperature), blue, and white (hottest stars). |
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Term
| Describe the different sizes of stars. |
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Definition
| Stars can be very small dwarf stars, medium-sized stars like our Sun, or giant and super giant stars. |
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Term
| What is an astronomical unit? |
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Definition
| An astronomical unit is a unit of measurement (like a meter) that is used to measure distances in our solar system. (It is the distance from the Sun to the Earth.) |
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Term
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Definition
| A light year is a unit of measurement (like a kilometer) that is used to measure distances in our universe. A light year is the distance light travels in a year or about 9.5*10^12 Km or 9,500,000,000,000 Km. |
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Term
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Definition
| Stars are a source of light because they release energy. |
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Term
| In space, why do moons and planets "shine"? |
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Definition
| Moons and planets shine because they reflect the light from stars. Moons and planets do not shine by their own light. |
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Term
| What types of objects are found in our solar system? |
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Definition
Our solar system consists of planets, planetary satellites like moons, comets (mostly made of ice), and asteroids (rocks) that orbit the sun.
Order of solar system:
Small, Solid, Rock-like planets: Mercury, Venus, Earth, Mars, Asteroid Belt (many asteroids),
Giant, Gas planets: Jupiter, Saturn, Neptune, (Pluto),
Kuiper Belt, (various objects, source of short lived comets)
Oort Cloud (may contain comets) |
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Term
| How do you find the position of an object? |
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Definition
| The position of an object is found by finding the distance and direction from a reference point. |
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Term
| What is a reference point? |
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Definition
| A reference point is an object that appears to be stationary and is compared to other objects to determine position or movement. |
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Term
| How do we determine if an object is moving? |
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Definition
| Because objects are always "moving", scientists determine movement by comparing an object to a reference point. Movement is a change of distance from the reference point. |
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Term
| How do we find average speed? |
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Definition
| Average speed is determined by dividing the total distance by the total time. The speed along the object's path may vary (unlike with constant speed that stays the same.) |
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Term
| Solve problems involving speed, distance, and time. |
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Definition
| Use formulas V=D/T, D=V*T, T=D/V. Don't forget to find the total distance and the total time. |
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Term
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Definition
| Velocity includes both the speed and the direction of an object. |
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Term
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Definition
| Velocity can change when an object accelerates by going faster, going slower, or changing direction. |
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Term
| How can we show motion on a graph? |
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Definition
| Motion can be shown on a graph by plotting the position and time or plotting the speed and time or plotting distance and time. |
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Term
| What does the slope of a line in a distance-time graph show? |
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Definition
| The slope of a line in a distance-time graph shows the speed of an object. The steeper the slope, the faster the speed. A horizontal line means no movement has occurred. |
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Term
| What can be determined from a speed-time graph? |
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Definition
| You can use a speed-time graph to determine the distance an object has traveled. (A horizontal line means a distance has been traveled.) |
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