2024-25 Grade 7 First Six Weeks Test Review

Which item listed below is NOT considered an element?

• calcium

• water

• phosphorus

• sulfur

Why is the periodic table called “The Periodic Table of Elements” and not “The Periodic Table of Compounds”?

• Because the periodic table lists all known pure substances in the universe.

• Because the periodic table was created before compounds were fully understood.

• Because the periodic table cannot show which elements readily react to form compounds.

• It would not matter if it were called “The Periodic Table of Compounds” since the words element and compound mean the same thing.

Baking soda is a common household chemical compound. The chemical formula NaHCO₃ represents the matter needed to produce baking soda. Baking soda is considered a compound because -

• Baking soda reacts when combined with vinegar, and chemicals that undergo reactions must be compounds.

• Baking soda is not a compound because it does not contain any of the noble gases.

• Baking soda contains more than one element that has chemically combined.

• Baking soda contains 3 atoms of oxygen, and to be a compound matter must contain more than one atom.

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Rebecca is using the chemical formulas for various substances to classify them as either a compound or an element. How should Rebecca classify Gold (Au)?

• Gold is a compound composed of a blend of substances.

• Gold is an element composed of a blend of substances.

• Gold is a compound composed of a pure substance.

• Gold is an element composed of a pure substance.

The chemical formula for glucose, a simple sugar, is C₆H₁₂O₆. The formula for ethanol, a fuel additive, is C₂H₆O. What accounts for the differences in these compounds?

• The elements that make up glucose are different than the elements that make up ethanol.

• The ratio of the elements is different in ethanol than in glucose.

• The chemical properties of the elements that make up the compounds are different.

• Glucose has more elements than ethanol.

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Acetic acid is a compound found in vinegar. The chemical formula for acetic acid is CH₃COOH. How many different elements are in acetic acid?

• 3

• 5

• 6

• 8

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Which of the following contains the greatest number of elements?

• S₈

• CH₄

• AlCl₃

• HNO₂

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Which of these is the positive particle found in the nucleus of an atom?

• neutrons

• protons

• the mass of an atom

• electrons

Which of the following pure substances form when two or more different elements are chemically combined? Select TWO correct answers.

• aluminum

• sodium bromide

• water

• mercury

• lead

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Which statements accurately describe the substances shown in the table? Select TWO correct answers.

• All substances in Group A can be broken down into two or more different types of matter.

• Fe2O3 is made up of five different types of matter.

• O2 is a molecule made up of two atoms, but not a compound.

• All substances in Group B are considered compounds because they are made of one type of matter.

• All substances in Groups A and B are considered elements because they can be broken down into two or more types of matter.

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