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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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