Chemical Composition & Properties – Chemistry Exam
The key terms of Chemistry Exam include, Chemical, Composition, Properties, Matter, Compound, Mixture.
Classify each of these samples of matter as an element, compound, or mixture.
table sugar
tap water
cough syrup
nitrogen
a)compound
b)mixture
c)mixture
d)compound
Write the chemical symbol for each element
lead
oxygen
silver
aluminum
Pb,O,Ag,Al
Name the chemical elements for each symbol: C, Ca, Fe, K, Au, Cu
carbon, calcium, iron, potassium, gold and copper
How does a chemical change affect the composition of matter?
the composition of matter always changes during a chemical change
Name four possible clues that a chemical change has taken place.
a transfer of energy, a change in color, the production of a gas and the formation of precipitate
Name two categories used to classify properties of matter.
Intensive and Extensive
Explain why all samples of a substance have the same intensive properties
every sample of a substance have the same chemical composition
Why can samples of gold(Au) and copper (Cu) have the same extensive properties but not the same intensive properties?
Samples of gold and copper can have the same mass and volume(extensive properties), but have different intensive properties because they have different chemical composition
Name three states of matter
solid, liquid and gas
Describe the two categories use to classify physical changes
reversible and irreversible
Is the freezing of mercury(Hg) a reversible or irreversible physical change?
Reversible because solid mercury can be melted
Which property most easily distinguishes sodium chloride (NaCl) from the other solids in Table 2.1?
Color-sodium chloride is the only white solid on the table
How are liquids and solids alike?How are they different?
They are alike because they have definite volumes but different because a solid has a definite shape while a liquid has an indefinite shape
What physical properties could be used to separate iron filings(Fe) from table salt(NaCl)?
Iron is magnetic, salt is not magnetic; salt dissolves in water, iron will not dissolve in water.
How are mixtures classified?
homogeneous of heterogeneous
What type of properties can be used to separate mixtures?
differences in physical properties such as: particle size, phase , solubility, boiling point
Explain the term phase as it relates to homogeneous and heterogeneous mixtures.
A phase is any part of a sample, with a uniform composition. There is one phase in a homogeneous mixture and two or more in a heterogeneous mixture.
Classify each of the following as a homogeneous or heterogeneous mixture:Food Coloring, Ice cubes in liquid water, mouthwash, and mashed, un-peeled potatoes
homogeneous, heterogeneous, homogeneous, and heterogeneous
How are a substance and a solution similar? How are they different?
Both substances, and a solution have a uniform composition throughout. For differences, a substance has a definite composition where as a a solution has a variable composition
When would you use filtration to separate a mixture? When would you use distillation to separate a mixture?
in a heterogeneous mixture;to separate a liquid from substances dissolved into liquids
Describe a procedure that could separate a mixture of sand and table salt.
Add water to the mixture to dissolve the salt, filter the mixtures the sand will remain in the filter paper, the salt solution will pass through, evaporate the water from the salt solution to obtain the salt
Liquid A and Liquid B are clear liquids. They are placed in evaporating dishes and allowed to evaporate. When evaporation is complete, there is a white solid container B but no solid in container A. What can you infer about the two liquids?
Liquid A is probably a pure substance while liquid B is a mixture
How is compound different from an element?
Compounds can be broken down into simpler substances by chemical means, but elements cannot be broken down further
How can you distinguish a substance from a mixture>
a substance has a fixed composition, whereas the composition of a mixture may vary
What are chemical symbols and chemical formulas used for?
Chemical symbols represent elements, chemical formulas represent compounds
Name two methods that can be used to break down compounds into simpler substance.
heat, electric current
Classify each of these samples of matter as an element, compound, or mixture.
table sugar
tap water
cough syrup
nitrogen
a)compound
b)mixture
c)mixture
d)compound
Write the chemical symbol for each element
lead
oxygen
silver
aluminum
Pb,O,Ag,Al
Name the chemical elements for each symbol: C, Ca, Fe, K, Au, Cu
carbon, calcium, iron, potassium, gold and copper
How does a chemical change affect the composition of matter?
the composition of matter always changes during a chemical change
Name four possible clues that a chemical change has taken place.
a transfer of energy, a change in color, the production of a gas and the formation of precipitate