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Chapter 9
Holt Science and Technology
25
Science
8th Grade
02/19/2014

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Term
Element
Definition
a pure substance that cannot be separated into simpler substances by physical or chemical means
Term
Name 3 Categories of elements
Definition
Metals, nonmetals, metalloids
Term
Properties of metals
Definition
on left side of periodic table
conduct heat and electricity
shiny
malleable (beaten into sheets)
ductile (wires)
have very few valence e-
Term
properties of nonmetals
Definition
are on the right side
dull
not malleable, ductile
brittle if a solid
most are gases
have a lot of valence e-
Term
metalloids
Definition
have properties of both metals and nonmetals
tough zig zag line
some shiny some dull
semi-conductive
Term
Compounds
Definition
pure substances made of two or more atoms bonded together
chemically combined
Ex; H2O
cpds can be broken down into the atoms that make them up, but msut be chemically separated since they are chemically combined
Term
Properties of Compounds
Definition
1. atoms must be in a certain ratio or amount
2. properties of compounds are different from the prop. of atoms that make it up
when the atoms chemically combine they get new properties because a new substance was formed NaCl
3. can be broken down into simpler substances but must be done chemically because they are joined chemically
Ex. run electricity through water to split into gas
Term
mixture
Definition
not pure
def-2 or more subs combined physically not chemically
they don't react together
Term
Properties of mixture
Definition
1. substances of a mixture keep their identity b/c no chemical change happened
ex. fruit salad
2. can be separated by physical methods Ex. pick it out with magnets, evaporation, filter, distillation
3. components of mixture can be any ratio or amount
Term
Are mixtures pure?
Definition
not pure
Term
Homogeneous mixture
Definition
components appear same as one kind of substance
Term
2 Kinds of homogeneous mixtures
Definition
1. Solution 2. Colloid
Term
Solution
Definition
Two or more substances that are evenly distributed among each other
Term
2 parts of a solution
Definition
Solute- gets dissolved
Solvent- Does the dissolving
Term
Properties of a Solution
Definition
1.Don't settle out 2.Don't scatter light 3.Can't be separated by filtering 4.dissolves
Term
Concentration
Definition
How much solute is dissolved
Term
Dilute
Definition
Weak
Term
Concentrated
Definition
strong
Term
Colloid
Definition
Mixture that has properties of solutions and suspensions
Term
4 properties of a colloid
Definition
1.Don't settle out 2.Don't dissolve 3.Do scatter light 4.Can't be separated by filtering
Term
4 examples of colloids
Definition
Mayo, fog, gelatin,, coolwhip
Term
heterogeneous mixture
Definition
a mixture in which componets can be identified by sight
Term
name a kind of heterogeneous mixture
Definition
suspension
Term
list the 4 properties of a suspension
Definition
do settle out, scatter light, don't dissolve, can be separated by filtering
Term
name 4 examples of suspension
Definition
muddy water, snow globe, paint, liquid antibiotic
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