Card Set Information
What is a pure substance that cannot be seperatedinto simpler substances by physical means
What are three examples of naturally occuring elements?
Copper, oxygen, gold
is the first letter in the symbol always capitalized?
how much mass of the universe does hydrogen make up?
what is one of the least abundant naturally occurring element
in _____ the russian chemist__ __ made a significant contribution to the periodic table
how does the periodic table organize the elements
into a grid of horizontal rows called periods and vertical columns called groups or families
how was he able to predict the properties of elements that were not yet discovered?
By analyzing the similarities among the elements and their pattern of repitition
how many known compounds are there?
What is the compound for table salt
One part sodium and one part chlorine
Unlike elements,______ can be broken down into simpler substances by chemical means
to seperate a compound into its elements often requires external_ such as ____ or _
the ____ of a compound are different from those of its component elements
what is the law of definite proportions?
regardless of the amount a compound is always composed of the same elements in the same proportion by mass
what is the law of multiple proportions
when different compounds are formed by a combination of the same elements different masses of one element combine with the same relative mass of the other element in a ratio of small whole numbers
matter that has a uniform and unchanging composition is a ________
Physical properties describe ______ _________, too. because substances have uniform and unchanging compositions, they have consistent and unchanging__________ ________as well
explain how intensive physical properties were used during the california gold rush?
Miners relied on gold characteristic density to seperate valuable gold containing flakes from riverbed sand.
what is the difference between pyrite and gold
they are different samples of matter and the look the same byt their desity is different
the ability of _to rust when combined with air is an example of a _____ ____________of iron
the properties of water are _________ diferent under different conditions
what are four examples of solids
wood, iron, paper, and sugar
what are examples of liquids
water, blood, and mercury
what are examples of gases?
neon, methane, air
how many eloements on earth occurr naturally
EACH ELEMENT HAS A UNIQUE ____ANDSYMBOL
the 91 naturally occurring elements are not equally ________
__ and___ together comprise almost_ of the mass of earths crust, while oxygen, carbon, and hydrogen account for more than _ of the human body
oxygen and silicon
how much of the above element is dispersed throughout the earths crust
how did dmitri mendeleev organize the periodic table
he made a chart of rows and columns based on their similarities and masses
what was the BRILLIANT aspect of Mendeleevs original table
it structure could accomodate elements that were not known at the time
what is a compound
a combination of two or more different elements that are combined chemically
______ that naturally occurr are more stable than the individual comonent elements
what is the percent by mass equation?
mass of element *
mass of compound
changes which alter a substance without changing its composition are __________ changes
as _____ and _____ change most substances undergo a change from one state to another
temperature and pressure
a _ is a combination of two or more pure substances in which each pure substance retains it idividual chemical _____