Chemistry

The idea of arranging the elements in the periodic table according to their chemical and physical properties is attributed to

• a. Mendeleev
• b. Moseley
• c. Bohr
• d. Ramsay

Which change results in the formation of different substances?

• burning of propane
• solidification of water
• melting of NaCl(s)
• freezing of CO2(g)

What is the difference between the substances represented by the symbols Co and CO?

• ❍ A They are two different ways to represent the element cobalt.
• ❍ B One is the symbol for an element, and one is a formula for a compound.
• ❍ C Co represents the element cobalt, and CO represents the element copper.
• ❍ D They represent two substances, each made up of two elements

Orange juice is classified as a -

• Compound because the composition of its atoms is fixed.
• Compound because the composition of its atoms can vary.
• Mixture because the composition of its components is fixed.
• Mixture because the composition of its components can vary.

Predict the missing product CH4 + O2 → ________ + H20

• C2
• H2
• CO2
• CH2

What was Mendeleyev’s purpose for reorganizing the periodic table?

• ❍ A He wanted to fit all the elements on one page instead of in a long line.
• ❍ B He wanted to put elements with similar characteristics in the same column.
• ❍ C He wanted to order the elements from the lightest to the heaviest.
• ❍ D He wanted to put all the metals on one side of the table and gases on the other

Which property is not a physical property?

• Mass
• Volume
• Flammability
• Shape

Which of the following is a pure substance?

• cereal
• koolaid
• vinegar
• Air

A chemical compound

• a. is the same as a mixture
• b. has the same properties as the elements it is made of
• c. can be seperated using physical properties
• d. is chemically combined and has different properties from individual elements

Select the true statement

• 1. A pure substance made of two or more elements that are chemically combined is a mixture.
• 2. An element is a pure substance that cannot be broken down into any other substances by chemical means.
• 3. During a chemical change, the form of a substance is altered, but not its identity.
• 5. Ice is an example of the liquid state of matter.