YEAR 7 SCIENCE - ATOMS, ELEMENTS, MOLECULES AND COMPOUNDS Flashcards
To learn all about everything related to matter.
WHAT IS AN ATOM?
AN ATOM IS THE SMALLEST PARTICLE OF A CHEMICAL ELEMENT THAT CAN EXIST.
FOR EXAMPLE: H2O (WATER) - THERE ARE 2 ATOMS IN HYDROGEN AND 1 IN OXYGEN
WHAT IS AN ELEMENT?
AN ELEMENT IS A SUBSTANCE MADE UP OF ONLY ONE TYPE OF ATOM.
ELEMENTS ARE LISTED ON THE PERIODIC TABLE
FOR EXAMPLE: CH3COOH to break this down: C= CARBON H= HYDROGEN (their are 3 atoms) C= CARBON O= OXYGEN O= OXYGEN H= HYDROGEN (THERE ARE 3 ELEMENTS IN THIS COMPOUND = carbon, hydrogen and oxygen)
WHAT IS A COMPOUND?
A COMPOUND IS A SUBSTANCE MADE UP OF ATOMS OF 2 OR MORE ELEMENTS THAT ARE CHEMICALLY BONDED TOGETHER
FOR EXAMPLE: CARBON DIOXIDE (CO2) IS A COMPOUND BECAUSE IT CONTAINS 2 OR MORE ELEMENTS CHEMICALLY BONDED TOGETHER)
WHAT IS A MOLECULE?
A MOLECULE IS MADE UP OF A SMALL GROUP OF ATOMS OF THE SAME ELEMENT BONDED TOGETHER.
THEY ARE MADE UP OF ONLY NON-METAL ATOMS.
CAN ALSO BE AN ELEMENT.
FOR EXAMPLE: O2 (OXYGEN) IS A MOLECULE
WHAT IS A MIXTURE?
A MIXTURE IS 2 OR MORE SUBSTANCES THAT ARE NOT CHEMICALLY COMBINED.
WHAT IS A HETEROGENEOUS MIXTURE?
HETERO MEANS DIFFERENT.
THIS IS A TYPE OF MIXTURE IN WHICH ALL THE COMPONENETS ARE COMPLETELY MIXED AND ALL THE PARTICLES CAN BE SEEN UNDER A MICROSCOPE.
THERE ARE 2 OR MORE PHASES.
IT CAN BE SEPARATED OUT PHYSICALLY
WE CAN JUDGE A HETEROGENEOUS MIXTURE BY JUST SEEING IT.
FOR EXAMPLE: A MIXTURE OF SODIUM CHLORIDE AND SAND
CHICKEN NOODLE SOUP IS ANOTHER EXAMPLE.
SAND, OIL AND WATER COMBINED IS ANOTHER EXAMPLE
WHAT IS A HOMOGENEOUS MIXTURE?
HOMO MEANS THE SAME.
IT HAS ONLY ONE PHASE.
IT HAS A UNIFORM COMPOSITION.
IT CANT BE SEPARATED OUT PHYSICALLY.
FOR EXAMPLE: SALT WATER IS HOMOGENEOUS DUE TO THE EVEN DISTRIBUTION OF THE DISSOLVED SALT THROUGHOUT THE ENTIRE SAMPLE OF SALTWATER.
SOFTDRINK IS A HOMOGENEOUS MIXTURE AS ALL THE COMPONENTS LIKE SWEETENER, CARBON DIOXIDE AND WATER FORM A SINGLE PHASE AND EVENLY DISTRIBUTED.
WHAT ARE SUSPENSIONS?
IS A HETEROGENEOUS MIXTURE WHERE A SOLID PARTICLE DOES NOT DISSOLVE IN A LIQUID SOLUTION.
FOR EXAMPLE:
MUDDY WATER - WHERE SOIL PARTICLES ARE SUSPENDED IN WATER.
FLOUR SUSPENDED IN WATER.
SAND SUSPENDED IN WATER.
BOILING SPAGHETTI
DEFINE PURE SUBSTANCES?
PURE SUBSTANCES ARE ELEMENTS AND COMPOUNDS.
FOR EXAMPLE: GOLD, SILVER, HELIUM, PURE WATER, TABLE SALT, BRONZE
ELEMENTS ARE EASY EXAMPLES OF PURE SUBSTANCES.
COMPOUNDS ARE PURE SUBSTANCES TOO : WATER, SODIUM CHLORIDE AS THEY HAVE CHEMICAL FORMULAS THAT TELL YOU HOW MANY ATOMS THEY CONTAIN. WATER (H2O) HAS 2 ATOMS.
BE CAREFUL THOUGH AS TAP WATER MAY CONTAIN IMPURITIES WHEREAS DISTILLED WATER IS.
EXAMPLES OF SUBSTANCES THAT ARE NOT PURE:
ROCKS, SHOES, SANDWICHES, LIGHT BULBS
WHAT IS A SOLUTION?
A SOLUTION IS A MIXTURE WHERE THE SOLIDS BREAK UP INTO SMALLER PIECES AND ARE NOT VISIBLE TO THE EYE - THEY ARE TRANSPARENT.
WHAT DOES SOLUBLE MEAN?
SOMETHING THAT WILL DISSOLVE
FOR EXAMPLE: SUGAR WILL DISSOLVE IN WATER
WHAT DOES INSOLUBLE MEAN?
WHEN IT CANNOT DISSOLVE IN SOMETHING
FOR EXAMPLE: SAND DOES NOT DISSOLVE IN WATER
WHAT DOES SATURATED MEAN?
WHERE A SOLUTION OF A SUBSTANCE CAN NO LONGER DISSOLVE NO MORE OF THAT SUBSTANCE. IT WILL LEAVE THE UNDISSOLVED SUBSTANCES AT THE BOTTOM.
FOR EXAMPLES:
MILO ADDED TO MILK CAN CREATE SATURATION AT THE POINT THAT NO MORE MILO CAN BE ADDED.
WHAT DOES UNSATURATED MEAN?
UNSATURATED SOLUTIONS ARE SOLUTIONS IN WHICH THE AMOUNT OF DISSOLVE SOLUTE IS LESS THAN THE SATURATION POINT OF THE SOLVENT.
FOR EXAMPLE: SALT IN WATER, SUGAR IN WATER , ICED TEA AND COFFEE
WHAT DOES SOLUTE MEAN?
SOLUTE IS THE SOLID THAT HAS DISSOLVED.
FOR EXAMPLE: IN A SOLUTION OF SALTY WATER, SALT IS THE SOLUTE
DEFINE ‘BOILING’
THE BOILING POINT OF PURE WATER IS 100 DEGREES CELCIUS.
WHEN A LIQUID BOILS, ALL THE LIQUID IS TRYING TO TURN INTO GAS AT THE SAME TIME.
BOILING HAPPENS AT THE LIQUIDS BOILING POINT (100 DEGREES)
GAS FORMED INSIDE THE LIQUIRD MAKES BUBBLES THAT RISE TO THE SURFACE.
THINK OF A KETTLE.
