STAAR Science

A compound secreted by honeybees to paralyze intruders in their hive is known as 2-heptanone. The formula for this compound is shown.

CH₃C₄H₈COCH₃

How many atoms of each element are in one molecule of

2-heptanone?

• 4 carbon atoms, 11 hydrogen atoms, and 1 oxygen atom

• 7 carbon atoms, 14 hydrogen atoms, and 1 oxygen atom

• 7 carbon atoms, 11 hydrogen atoms, and 8 oxygen atoms

• 6 carbon atoms, 14 hydrogen atoms, and 3 oxygen atoms

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NGSS.MS-PS1-1

Barium sulfate, BaSO₄, is a white crystalline solid that is insoluble in water. It is used by doctors to diagnose problems with the digestive system. Barium hydroxide, Ba(OH)₂, is also a white crystalline solid and is used in wastewater treatment.

How many more oxygen atoms are represented in the formula for barium sulfate that in the formula for barium hydroxide?

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NGSS.MS-PS1-1

The table lists some compounds found in foods and their formulas.

Bases on this information, which of these statements is NOT true?

• A molecule of sorbitol contains three more oxygen atoms that a molecule of glutamine does.

• A molecule of lactose contains twice as many atoms as a molecule of fructose does.

• A molecule of fructose contains four more atoms than a molecule of glutamine does.

• A Molecule of lactose contains twice a many carbon atoms as a molecule of sorbitol does.

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NGSS.MS-PS1-1

A student is using colored beads to make a model of aluminum sulfate, Al₂(SO₄)₃. Aluminum atoms are represented by blue beads, sulfur atoms by yellow beads, and oxygen atoms by green beads.

What combination of beads should the student use for the model?

• 6 blue, 3 yellow, and 7 green

• 2 blue, 1 yellow, and 4 green

• 2 blue, 3 yellow, and 12 green

• 6 blue, 12 yellow, and 12 green

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NGSS.MS-PS1-1

Strontium phosphate, Sr₃(PO₄)₂, is a crystalline substance used in medicine and industry. How many phosphorus atoms are represented in the formula for Sr₃(PO₄)₂?

• 2

• 3

• 4

• 8

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NGSS.MS-PS1-1

In which of these compounds are there twice as many oxygen atoms as hydrogen atoms?

• H₃PO₄

• H₂SO₄

• HClO₃

• H₂O

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NGSS.MS-PS1-1

The chemical formula for sodium sulfate is Na₂SO₄. How many sulfur atoms are in the formula for sodium sulfate?

• 1

• 2

• 6

• 7

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NGSS.MS-PS1-1

Serotonin is a chemical substance that acts as a neurotransmitter. It helps relay messages in the human brain. The formula for one molecule of serotonin is shown below.

C₁₀H₁₂N₂O

How many atoms in all are in a molecule of serotonin?

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NGSS.MS-PS1-1