Question

1) Classify each of the following as a mixture, a compound, or an element?

table sugar, propane, bronze, tea, vinegar, dry ice, oxygen, aluminum

2) Select the statements that pertain to elements. Select all the statements that apply.
a) These can be broken down by physical means.
b) These cannot be broken down by chemical means.
c) These combine chemically to form new substances; they are building blocks of matter.
d) These are chemical combinations of simpler forms of matter.
e) These are pure substances.

3) Which of the following are chemical changes? Check all that apply.
a) sugar is dissolved in water
b) a warm coke bottle fizzes when opened
c) the copper roof turns green over time
d) baking soda is dissolved in vinegar and bubbles appear
e) a fog appears on your windshield in cold weather

4) Classify each property as physical or chemical.

a)susceptibility to rust

b) flammability

c) boiling point

d) melting point

e) conductivity

f) color

5) Which of these substances are elements? Check all that apply.

a) silicon

b) iodine

c) lead

d) quartz

e) silicone

f) water

Answer 1

Answer 1) :

Bronze is the mixture of copper and zinc. Tea is mixture of various natural products. Vinegar is the homogenous mixture of acetic acid and water. Table sugar is the compound made up of carbon, hydrogen and oxygen. Propane is compound made up of carbon and hydrogen and dry ice is the solid carbon dioxide made up of carbon and oxygen. Aluminium and oxygen are elements

Mixture: bronze, tea, vinegar.

Compound: table sugar, propane, dry ice.

Element: aluminum, oxygen.

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Answer 2):

Elements are the pure substances which can not be broken down by chemical means. Elements combine chemically to form new substances.

b) These cannot be broken down by chemical means.

c) These combine chemically to form new substances; they are building blocks of matter.

e) These are pure substances.

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Answer 3):

Chemical changes are those changes which results in formation of new chemicals. Copper reacts with atmospheric oxygen to form green oxide. Baking soda reacts withh vinegar to form bubbles of carbon di oxide.

c) the copper roof turns green over time

d) baking soda is dissolved in vinegar and bubbles appear

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Answer 4):

Physical properties are those properties, which can be observed without change in identity of substance and chemcal properties involve change in identity of substance.

Physical properties:

c) boiling point

d) melting point

e) conductivity

f) color

Chemical properties:

a)susceptibility to rust

b) flammability

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Answer 5):

Quatz and silicone contains combination fo silicon and oxygen. Water contains combination of oxygen and hydrogen. Silicon, iodine and lead are pure elements.

Elements: silicon, iodine, lead.