Unit 1 Chemistry Test
How many elements occur naturally?
92
Law of Definite Proportions
A compound is always composed of the same elements in the same proportion by mass
Weight
A measure of not only the amount of matter, but the gravitational pull
Mass
A measurement that reflects the amount of matter
Alloy
A solid-solid solution
An explanation of natural phenomenon based on many observations and investigations over time?
A theory
Chemical Property
Ability of a substance to change into a new substance
Why is the term periodic used?
Because you periodically find similar elements
Physical Change
Change that alters the substance without changing its composition
Chemical Change
Change where a substance changes to a new substance (chemical change)
Physical Property
Characteristic that can be observed without changing its composition
When components of a mixture can be drawn across the surface of another material, which technique can be used?
Chromatography
Heterogeneous mixtures can either be a _______ or a ________
Colloid or a Suspension
Examples of Extensive Physical Properties
Color, density, odor
What separation technique is used in making rock candy?
Crystallization
Examples of physical changes
Cutting, breaking, burning
Examples of Physical Properties
Density, color, odor
What is distillation based on?
Difference in the boiling points with the substances used.
What are separation techniques based on?
Differences in the physical properties of a substance
What are the vertical columns called?
Families or Groups
What separation technique is used to separate a solid-liquid heterogeneous mixture?
Filtration
Is ozone good or bad?
Good in the stratosphere, bad near the surface
What kind of mixture can be usually separated by distillation?
Homogeneous
What types of mixtures are there?
Homogeneous (Solution) and Heterogeneous
What is the most abundant one in the universe?
Hydrogen
What is qualitative data?
Information that describes color, odor, shape and physical characteristics
Which law states 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 ration of whole numbers?
Law of multiple proportions
Substance
Matter with uniform and definite composition (Elements, compounds)
Who is the father of the modern periodic table
Mendeleev
Examples of heterogeneous mixtures (Colloids)
Milk, jello, fog, butter
Are solutions always liquid?
Nope
How can a chemical compound be separated?
ONLY with a chemical reaction
Examples of heterogeneous mixtures (Suspensions0
Orange juice with pulp, Italian Dressing
What are the horizontal rows called?
Periods
Mixture
Physical blend of 2 or more substances- not chemically combined
Extensive Physical Property
Property that doesn't depend on the amount present
One thing to remember about this unit
Rules that determine types of mixtures aren't absolute
Examples of chemical properties
Rusting, corrodes, burns
When no exceptions are found in a relationship in nature and it is tested by many experiments, we call it a?
Scientific Law
Precipitate
Solid that forms and settles out of a liquid mixture
Chemical property (Cont.)
Something you observe during a chemical reaction
What is the process where a solid changes to a vapor directly?
Sublimation
What are the types of Matter?
Substance and Mixture
Examples of homogeneous (small) mixtures
Sugar water, tap water, air, steel
Which elements have similarities to each other?
The ones in the same family or group
We better define chemistry as?
The study of matter and the changes it undergoes
Phase change
Transition of matter from one state to another (physical change)
How do the properties of the elements compare to that of the compound
VERY different
How would sublimation separate two solids?
When one substance sublimates and the other doesn't
What does a chemical formula tell us?
Which elements and their ratio.
Evidence of chemical changes
fire, rust, odor, color change
