CHAPTER TWO: MATTER AND ENERGY Flashcards
The EARLY GREEK PHILOSOPHERS (6th Century B.C.) proclaimed the existence of _______ and a ________.
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Atoms and a Void.
What is ALCHEMY (1st-16th Century A.D.)?
What are some of the contributions of this tradition?
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Alchemy is the early study of chemistry.
Contributions:
- qualitative experimentation
- important techniques
- methods
- glassware
What are the contributions of the MEDICAL-TECHNOLOGICAL tradition (13th-17th century A.D.)?
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- quantitative experimentation
- balances
- furnaces
- crucibles
What are the three forms that MATTER takes? Describe each one….
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SOLID: has a definite shape and volume. Strong attractive forces hold the particles such as atoms or molecules close together. The particles are arranged in such a rigid pattern they can only vibrate slowly in fixed positions.
LIQUID: has a definite volume, but not a definite shape. The particles move in random directions but are sufficiently attracted to each other to maintain a definite volume, although not a rigid structure (takes the shape of the container).
GAS: does not have a definite shape or volume. The particles are far apart, have little attraction to each other, and move at high speeds, taking the shape and volume of their container.
What is a PURE SUBSTANCE/CHEMICAL and
what are the TWO kinds of pure substances?
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A pure substance/chemical is MATTER that has a fixed or definite composition.
The two kinds of pure substances are ELEMENTS and COMPOUNDS.
What is an ELEMENT?
Give 5 examples of an element
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An element is the simplest type of a pure substance.
It is composed of only ONE type of material. Every element is composed of ATOMS that make up each type of matter. (Ex: silver is composed of silver atoms, iron of iron atoms, etc.)
ELEMENTS:
- elemental iron: Fe (solid)
- elemental bromine: Br2 (liquid)
- elemental hydrogen: H2 (gas)
- argon: Ar (gas)
- oxygen: 02
What is a COMPOUND?
Give 3 examples of compounds.
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A compound is also a pure substance, but it consists of atoms of two or more elements always chemically combined in the same proportion.
In compounds, the atoms are held together by attractions called BONDS, which form small groups of atoms called MOLECULES. (Ex: H20- water and H202- hydrogen peroxide…are different compounds, which means they have different properties)
COMPOUNDS:
- H20 (l)
- C12H22O1 (s)
- NaCl
An important difference between COMPOUNDS and ELEMENTS is that compounds can be ____________, whereas elements ____________.
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An important difference is that COMPOUNDS can be broken down by chemical processes (not physical methods) into simpler substances, whereas ELEMENTS cannot be broken down further by a chemical reaction.
What is a MIXTURE?
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In a MIXTURE, two or more substances are physically mixed, but not chemically combined (ex: air, steel, tea).
In any mixture, the proportions of the components can vary.
Why can physical processes be used to separate MIXTURES?
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because there are no chemical interactions between the components (ex: a mixture of different coins)
What are the two types of MIXTURES? Describe each and give examples of each….
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HOMOGENEOUS: also called a SOLUTION; the composition is uniform throughout the sample. Ex: air, sea water. Examples:
- NaCl
- air (80%N2, 20% 02, <1% other gases)
- alloys: bronze and brass
HETEROGENEOUS: the components do not have a uniform composition throughout the sample. Ex: oil and water, bubbles in a soda. Examples:
- blood: is a suspension
- milk: is a colloid
List two ways that mixtures are separated by various methods:
- solids separated from liquids by….
- different compounds of a liquid mixture by….
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Solids are separated from liquids by FILTRATION, which involves pouring a mixture through a filter paper set in a funnel.
In CHROMATOGRAPHY, different components of a liquid
mixture separate as they move at different rates up the surface of a piece of chromatography paper.
Changes of State (when matter is converted from one state to another- what are each of these called and what happens?):
- solid to liquid = ________
- liquid to solid= _______
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- MELTING -when heat is added to a solid, the particles move faster. At a temp called the MELTING POINT (mp), the particles of a solid gain sufficient energy to overcome the attractive forces that hold them together. The particles separate and move about in random patterns
- FREEZING- if the temperature is lowered, kinetic energy is lost, the particles slow down, and attractive forces pull the particles close together. The liquid changes to a solid at the FREEZING POINT (fp) which is the same temperature as its melting point. Every substance has its own freezing (melting point).
- vaporization
- condensation
- sublimation
- deposition
During a change of state, the temperature of a substance _______ ________.
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Remains constant.
What are PHYSICAL PROPERTIES?
List 5 typical physical properties in chemistry.
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PHYSICAL PROPERTIES are those characteristics that can be observed or measured without affecting the identity of a substance.
5 typical physical properties in chemistry:
- appearance: color, shape
- melting point
- boiling point
- conductivity: thermal or electrical
- solubility
Water is a substance that is commonly found in all three states- solid, liquid and gas. When matter undergoes a PHYSICAL CHANGE, its state or appearance changes and its composition __________.
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Remains the same (all three states are water).
In a PHYSICAL CHANGE OF STATE, are new substances produced?
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NO
Ex: if you dissolve salt in water, the appearance of the salt changes, but you can re-form the salt crystals by heating the mixture and evaporating the water.
What are CHEMICAL PROPERTIES?
When a CHEMICAL CHANGE takes place, the original substance ____________________…
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CHEMICAL PROPERTIES are those that describe the ability of a substance to change into a new substance.
When a CHEMICAL CHANGE takes place, the original substance is converted into one or more new substances, which have different physical and chemical properties.
Ex: chemical properties of Na react with H20 to give Na0H….or with 02 to give Na20
What is the NORMAL BODY TEMPERATURE range?
What is hyperthermic in degrees C and degrees F?
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98.6 +or-2.0 degrees F
Hyperthermic:
- > 41 degrees C
- > 106 degrees F
One degree Celsius = ______ K
One degree Fahrenheit= _____ C + ______
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degree C= 273 K
degree F= 9/5 degree C + 32
Define ENERGY
What is the formula for WORK?
What is the formula for FORCE?
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Energy is the ability to do work (to accelerate a mass through a distance).
WORK= FORCE x DISTANCE
FORCE= MASS x ACCELERATION x DISTANCE
What is HEAT (also known as _______)……?
What does TEMPERATURE measure?
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Heat (also known as thermal energy) is the energy associated with the motion of particles.
Temperature is a measure of average kinetic energy of the particles of a substance
What are two forms of energy? Define each one.
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POTENTIAL ENERGY- stored energy due to:
* location (A boulder resting on top of a mountain has potential energy because of its location- if it rolls down the mountain, the potential energy becomes kinetic energy)
- OR chemical composition (foods and fossil fuels have potential energy in their molecules- when you digest food or burn gasoline in your car, potential energy is converted to kinetic energy to do work)
KINETIC ENERGY- energy of motion; any object that is moving has kinetic energy.