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JOAN CARTAN-HANSEN,
HOST: HOW DO YOU KNOW WHAT IS IN
COMPOUND?
YOU FIND OUT ITS CHEMICAL
FORMULA.
FIRST, EVERY ELEMENT HAS ITS OWN
SYMBOL.
FOR EXAMPLE, SODIUM IS LISTED AS
NA.
WHEN YOU COMBINE ONE ION OF
SODIUM WITH ONE ION OF CHLORINE
IN A ONE TO ONE RATIO, YOU GET
NACL OR SODIUM CLORIDE.
WE KNOW THAT AS SALT.
SO, SALT'S CHEMICAL FORMULA IS
NACL.
SOMETIMES YOU HAVE MORE THAN ONE
ATOM OF AN ELEMENT IN A
COMPOUND.
WATER'S CHEMICAL FORMULA IS H20.
THE SMALL LOWER 2 TELL YOU THAT
THERE ARE TWO ATOMS OF HYDROGEN
FOR EVERY ONE ATOM OF OXYGEN IN
WATER.
AND HOW DO SCIENTISTS DECIDE THE
ORDER OF ELEMENTS IN A CHEMICAL
FORMULA?
IN THE HILL METHOD, CARBON GOES
FIRST, THEN HYDROGEN THEN THE
OTHER ELEMENTS FOLLOW
ALPHABETICALLY.
SO, A CHEMICAL FORMULA IS A LIST
OF THE TYPE AND NUMBER OF
ELEMENTS FOUND IN A COMPOUND.
FOR MORE INFORMATION, CHECK OUT
THE SCIENCE TREK WEBSITE.
YOU'LL FIND IT AT
IDAHOPTV.ORG/SCIENCE TREK
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