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An element is.....

• ...made up of lots of atoms

• ... is more than one kind of atom

• ...made up of one kind of atom

• .... made of one atom

  What is a pure substance made of two or more elements that are chemically combined called?

• A. element
• B. compound     
• C. mixture
• D. solution

Which of the following is not a compound?

• HCl
• Cl
• NaCl
• CO2

Which of the following represents an element?

• H₂O
• H₂
• NaCl
• CaCO₃

Which of the following are properties of compounds? Check all that apply.

• It takes a large amount of energy to separates the elements of a compound.

• The proportions of the elements in a compound are always fixed

• It is easy to separate the elements of a compound.

• The elements/components of a compound do not retain their individual properties.

Every water molecule has two hydrogen atoms bonded to one oxygen atom. This fact supports the concept that elements in a compound are

• chemically combined in a fixed proportion

• chemical combined in varying proportions

• physically mixed in a fixed proportion

• physically mixed in varying proportions

What is the definition of a Mixture?

• a combination of two or more materials that can be easily separated by some Chemical means.

• a combination of two or more materials that can be easily separated by some physical means.

Describe the melting and boiling points of pure substances

• Range of temperature

• Fixed

• Different temperature

Presence of impurities

• lowers the melting point of substances and raises the boiling point

• lowers the boiling point of substances and raises the melting point

• Has no effect on the boiling and melting points

• lowers the melting point of substances and lowers the boiling point

• raises the boiling point of substances and raises the melting point