Atom Counting and Coefficient Basics

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Answer explanation

A water molecule, H₂O, consists of 2 hydrogen atoms and 1 oxygen atom. Therefore, the correct answer is 2.

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Answer explanation

In the compound CO₂, the subscript '2' indicates that there are 2 oxygen atoms bonded to one carbon atom. Therefore, the correct answer is 2.

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Answer explanation

A molecule of CH₄ (methane) consists of 1 carbon atom and 4 hydrogen atoms. Therefore, the total number of atoms is 1 + 4 = 5. Thus, the correct answer is 5.

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Answer explanation

In the formula 2H₂O, the '2' indicates there are 2 water molecules. Each water molecule contains 2 hydrogen atoms, so 2 x 2 = 4 hydrogen atoms in total. Therefore, the correct answer is 4.

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Answer explanation

The compound C_6H_{12}O_6 indicates it has 6 carbon atoms, as represented by the subscript '6' in the formula. Therefore, the correct answer is 6.

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Answer explanation

The chemical formula NH₃ consists of 1 nitrogen (N) atom and 3 hydrogen (H) atoms. Adding these together gives a total of 4 atoms (1 + 3 = 4). Therefore, the correct answer is 4.

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Answer explanation

In the formula 3CO₂, the '3' indicates there are three molecules of CO₂. Each CO₂ molecule contains one carbon atom. Therefore, the total number of carbon atoms is 3, making the correct answer 3.

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Answer explanation

In 2NaCl, there are 2 sodium (Na) atoms and 2 chlorine (Cl) atoms. Adding them together gives 2 + 2 = 4 total atoms, making the correct answer 4.

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Answer explanation

In the compound H₂SO₄, there is 1 sulfur atom. The chemical formula indicates that sulfur (S) is present once, while hydrogen (H) and oxygen (O) are present in greater quantities.

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Answer explanation

In the compound 4H₂O, each water molecule (H₂O) contains 1 oxygen atom. Therefore, 4H₂O has 4 oxygen atoms (1 oxygen x 4 molecules = 4 oxygen). Thus, the correct answer is 4.