H Chemistry: Unit 2 Flashcards
pure substance
matter with a uniform and unchanging chemical composition
physical property
characteristic that can be observed without changing the chemical composition
intensive property
physical property that does not depend on the amount present
extensive property
physical property that depends on the amount present
malleable
able to be flattened into sheets
ductile
able to be drawn into a wire
chemical property
characteristic that can only be observed if the substance changes chemical composition
solid
definite shape, definite volume
liquid
takes on shape of its container, definite volume
gas
takes on shape & volume of its container
gas v. vapor
gas is a substance that is gaseous at room temperature, vapor is a substance in the gaseous state but a solid or liquid at room temperature
physical change
change in matter that does not change the chemical composition
chemical change
change in matter that forms a new substance with different physical and chemical properties(chemical reaction)
chemical equation
mathematical expression of a chemical reaction
Law of Conservation of Mass
matter cannot be created nor destroyed but must be conserved throughout chemical reactions
the mass of the reactants must
equal the mass of the products
mixture
combination of two or more pure substances that are physically combined
heterogeneous mixture
mixture that is not uniform throughout
homogeneous mixture
mixture that is uniform throughout(solution)
separating mixtures
because mixtures are physically combined, they cannot be physically separated based on their unique physical and chemical properties
distillation
separate a mixture through different boiling points
chromatography
separates liquids through molecular size
filtration
separates liquids through pore size
element
pure substance made of one type of atom that cannot be broken down by ordinary physical or chemical means
Dmitri Mendelev
organized elements by mass
row
period
column
group
compound
pure substance made of 2 or more atoms that can be broken down by chemical means
compounds have
different physical and chemical properties compared to the elements they are made from
Law of Definite Proportions
a compound contains the same proportions of elements no matter the amount or location by mass
Law of Multiple Proportions
if two compounds have the same elements but different properties, then the ratio of elements to each other differ
percent mass
ratio of the mass of an element to the mass of a compound expressed as a percentage