Pure substance or mixture?
Twenty single-part examples, questions only

11 multi-part examples

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Example #1: (a) In one lump, you have five grams of silver and, in another lump, five grams of gold. Pure substances or mixtures? (b) You melt the two substances and mix them throughly and allow it to become a solid lump. Pure substance or mixture?

Example #2: If you have ever had difficulty swallowing aspirin, you know it has an unpleasant taste. To help a child swallow aspirin, a parent may crush the tablet and add it to apple sauce. Is the aspirin-apple-sauce combination classified as a compound or a mixture? Is it homogeneous or heterogeneous? Explain the reason for your choices.

Example #3: Which of the following would best be described as a heterogeneous mixture?

(a) strawberry milk shake   (d) granite stone
(b) motor oil   (e) liquid nitrogen
(c) diamond   (f) cough syrup

Example #4: Which of the following is not a characteristic of a compound?

(a) It has different properties from the elements that formed it.
(b) It is a pure substance made of two or more different elements.
(c) Samples taken from different parts of a large amount of the compound will have different properties.
(d) It can be represented by a chemical formula.

Example #5: An example of a mixture is:

(a) the air in a room.
(b) all of these.
(c) gold.
(d) hydrogen fluoride.
(e) purified water.

Example #6: An example of a pure substance is:

(a) compound.
(b) carbon dioxide.
(c) elements.
(d) all of these above.
(e) pure water.

Example #7: Water is an example of:

(a) a heterogenous mixture.
(b) a compound.
(c) a homogeneous mixture.
(d) an element.

Example #8: Which of the following statement(s) is false? Why?

(a) Solutions are always homogeneous mixtures.
(b) The terms “atom” and “element” can have different meanings.
(c) Elements can exist as atoms or molecules.
(d) Compounds can exist as atoms or molecules.
(e) At least two of the four above statements are false.

Example #9: Why does the dissolved component not settle out of a solution?

Example #10: Which of the following statements is false?

(a) Two or more different substances combine physically to form a mixture.
(b) Two or more different atoms combine chemically to form a molecule.
(c) Two or more different atoms combine chemically to form an element.
(d) Two or more different elements combine chemically to form a compound.

Example #11: Which of the following is a pure substance?

colloid
mixture
element
solution

Example #12: Which of the following is a mixture?

steel
water
oxygen
gold

Example #13: A good definition of a chemical is any substance that:

causes corrosion
has definite composition
is hazardous
is used in industrial processes

Example #14: Matter that is free to move and fills its available volume is in the _____state.

liquid
solid
gaseous
Bose-Einstein

Example #15: The state of matter in which a material is most likely to resist compression is the _____ state?

solid
liquid
gaseous
plasma

Example #16: A chemical change occurs when

Dissolved minerals solidify to form a crystal
Ethanol is purified through distillation
Salt deposits form from evaporated seawater
A leaf changes color

Example #17: Which of the following shows a physical change occurring?

A peach spoils
A sterling silver spoon tarnishes
A copper statue turns green
A hot-glue gun melts a glue stick

Example #18: Which of the following is not a matter?

(a) sunlight
(b) copper wire
(c) alcohol
(d) dust

Example #19: Which has both a definite shape and definite volume?

(a) solid
(b) plasma
(c) gas
(d) liquid

Example #20: Which is a pure substance?

(a) element
(b) compound
(c) mixture
(d) both (a) and (b)

11 multi-part examples

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