has a uniform and unchanging composition in a substanc
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Solids
are a form of matter that have their own definite shape and volume
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Liquids
are a form of matter that have a definite volume but take the shape of the container
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Gasses
have no definite shape or volume. They expand to fill their container
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Vapor
refers to the gaseous state of a substance that is a solid or liquid at room temperature
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physical property
a characteristic that can be observed or measured without changing the sample’s composition
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Extensive properties
physical properties that are dependent on the amount of substance present, such as mass, length, or volume
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Intensive properties
physical properties that are independent of the amount of substance present, such as density, boiling point, or color
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Chemical property
The ability of a substance to combine with or change into one or more other substances, such as iron forming rust (4Fe +3Oz + 6H2O = 4Fe(OH)3), or copper turning green in the air (Cu(OH)2 + CuCO3 = Cu2(OH)2CO3)
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B
Density is what kind of property: A - atomic B - intensive C - extensive D - dependant
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Physical changes
A change that alters a substance without changing its composition
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Phase change
a transition of matter from one state to another, like boiling, freezing, melting, and condensing
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Chemical change
A change that involves one or more substances turning into new substances, like decomposing, rusting, exploding, burning, or oxidizing
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Melting
Solid becoming liquid
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Evaporation
Liquid becoming vapor
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Condensation
Vapor becomes liquid
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Freezing
Liquid becomes solid
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Law of conservation of mass
mass is neither created nor destroyed in a chemical reaction, it is conserved. The mass of the reactants equals the mass of the products. mass>reactants - mass>products
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Mixture
a combination of two or more pure substances in which each pure substance retains its individual chemical properties
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Homogenous mixture/solution
a mixture where the composition is constant throughout, like water
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heterogeneous mixture
a mixture where the individual substances remain distinct, like chicken soup
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Pure substance
An element or compound
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Filtration
a technique that uses a porous barrier to separate a solid from a liquid in a heterogeneous mixture, like a coffee maker
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Distillation
a separation technique for homogeneous mixtures that is based on the differences in boiling points of substance. The process of boiling one thing out of another.
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Crystallization
a separation technique for homogenous mixtures that results in the formation of pure solid particles from a solution containing the dissolved substance. by boiling the liquid, only the solid will be left.
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Sublimation
the process of a solid changing directly to a gas, which can be used to separate mixtures of solids when one sublimates and the other does not, like dry ice (frozen CO2)
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Chromatography
a technique that separates the components of a mixture on the basis of the tendency of each to travel across the surface of another material. Separating based on the polarity of the components.
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Element
a pure substance that cannot be separated into simpler substances by physical or chemical means
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92 elements
# of elements that occur naturally on earth
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periodic table
a tabular arrangement of the chemical elements according to atomic number as based on the periodic law
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compound
something made up of two or more elements combined chemically, like table salt, NaCl, and water, H2O. They can be separated.
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law of definite proportions
a compound is always composed of the same elements in the same proportion by mass, no matter how large or small the sample
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percent by mass
the ratio of the mass of each element to the total mass of the compound expressed as a percentage. Formula: percent by mass = (mass of element/mass of compound) x 100
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density
a ratio that compares the mass of an object to its volume
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observation
orderly, direct information gathering about a phenomenon
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proportion
the relation of one part to another or to the whole with respect to quantity