Chemie TBZ 1. Lehrjahr
Chapter 1,2 and 3
Chapter 1,2 and 3
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Flashcards
close, but free to flow is?
liquid
spaced relatively far apart is?
gaseous
packed tightly together is?
solid
The words gas and vapour can be used interchangeably.
The term gas is limited to those substances that exist in the gaseous state at …
room temerature
A physical change alters a given material without changing its chemical …
composition
What are some words that describe physical changes?
boil, freeze, melt, dissolve, condense, break, split, grind, cut, crush
»Physical changes that involve a change of state are always reversible.«
»Most samples of matter are mixtures.«
What is a mixture?
A mixture is a physical blend of two or more components.
»A heterogeneous mixture is one that has a completely uniform composition.«
Which term describes a part of a sample with uniform composition and properties?
How many phases exist in these types of mixtures?
homogeneous
heterogeneous
homogeneous 1
heterogeneous 2 or more
The process that separates a solid from a liquid in a heterogeneous mixture is called …
filtrieren
What happens during a distillation?
A liquid is boiled t produce a vapour (Dampf) that is them condensed knto a liquid.
All living and nonliving things are made up of building blocks called...?
elements
Name the two classifications of substances.
elements
compounds (Verbindungen)
»Elements can be easily separated into simpler substances.«
Compounds are substances that can be separated into simpler substances only by C means?
C = chemical
The properties of compounds are different from those of their component elements
Sodium chloride (table salt) is a C of sodium, which is a soft M, and chlorine, which is
a pale yellow G.
C= compound
M= metall
G= gas
Describe one way to decide whether a sample of matter is a substance or a mixture.
f the composition of a sample is fixed, the sample is a substance.
If the composition of a sample may vary, the sample is a mixture
What is used to represent an element?
A one- or two-letter chemical symbol.
What are chemical symbols used for?
To write the chemical formulas of compounds.
Subscripts in chemical formulas are used to indicate the R of the elements in the
compound.
R = realitve proportions
»The elements that make up a compound are always present in the same
proportions.«
Pb is the symbol for what element?
Plumbum, Blei, lead
What is the symbol for gold?
(Aurum) Au
Stibium is the Latin name for which element?
antimon
What is a chemical property?
The ability of a substance to undergo specific chemical change.
Eine chem. Eigen. lässt sich bei einer chem. Reaktion beobachten oder feststellen
»Chemical properties are observed only when a substance undergoes a chemical
change.«
What happens during a chemical reaction?
One or more substances change ito one or more new substances.
Ausgangsstoffe es entstehen andere Stoffe mit anderen Eigenschaften.
»A change in the composition of matter … occurs during a chemical reaction.«
Which of the following terms completes the sentence best?
List the four possible clues to a chemical change.
transfer of energy
change in colour
production of a gas
formation of a precipitate
»If you observe a clue for chemical change, you can be certain that a chemical change
has taken place.«
During a chemical reaction, the mass of the products is always equal to the mass of
the …
initiation substances/reactants
The law of conservation of mass states that in any physical change or chemical
reaction, mass is neither C nor D.
C D
C = created
D= destroyed
Democritus, who lived in Greece during the fourth century B.C., suggested that matter is made up of tiny particles that cannot be divided. He called these particles ?
atoms
List two reasons why the ideas of Democritus were not useful in a scientific sense.
They did not explain chemical behavior, and they lacked experimental support
because Democritus’s approach was not based on the scientific method.
The modern process of discovery about atoms began with the theories of an English
schoolteacher named?
John Dalton
