Counting Atoms

Front

What is an element?

Back

An element is a pure substance that cannot be broken down into simpler substances by chemical means. Each element is made up of atoms that have the same number of protons.

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How do you determine the number of different elements in a chemical formula?

Back

Count the unique symbols in the formula. Each symbol represents a different element.

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What does the subscript in a chemical formula indicate?

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The subscript indicates the number of atoms of the element present in the molecule. For example, in H2O, the '2' indicates there are two hydrogen atoms.

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What is a coefficient in a chemical equation?

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A coefficient is a number placed in front of a chemical formula to indicate how many molecules or moles of that substance are present. For example, in 4H2O, '4' is the coefficient.

Front

How many elements are in the compound NaHCO3?

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There are 4 different elements: Sodium (Na), Hydrogen (H), Carbon (C), and Oxygen (O).

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What is the formula for calculating the total number of atoms in a molecule?

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Add the number of atoms of each element together, considering their subscripts. For example, in C2H8O, there are 2 (C) + 8 (H) + 1 (O) = 11 total atoms.

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How many Sodium (Na) atoms are in the compound 6NaCl?

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There are 6 Sodium (Na) atoms, as indicated by the coefficient '6' in front of NaCl.

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What is the difference between a compound and a mixture?

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A compound is a substance formed when two or more elements chemically bond together, while a mixture is a combination of two or more substances that retain their individual properties.

Front

What does the chemical formula C2H6 represent?

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It represents a molecule of ethane, which contains 2 carbon atoms and 6 hydrogen atoms.

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How do you identify the number of atoms of a specific element in a compound?

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Look for the element's symbol in the formula and check the subscript. If there is no subscript, it means there is one atom of that element.