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 elements in a compound?

Back

Count the unique element symbols in the chemical formula. For example, in Mg2As3COHNi2, the elements are Mg, As, C, O, H, and Ni, totaling 6 elements.

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What does a subscript in a chemical formula indicate?

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

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How many hydrogen atoms are in 4H2O?

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There are 8 hydrogen atoms in 4H2O because each water molecule (H2O) contains 2 hydrogen atoms, and 4 times 2 equals 8.

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What is the significance of no subscript following an element symbol?

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If there is no subscript following an element symbol, it means there is only 1 atom of that element present in the compound.

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How many oxygen atoms are in H2O?

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There is 1 oxygen atom in H2O.

Front

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

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To calculate the total number of atoms, add the number of atoms of each element together, considering their subscripts.

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How many atoms of carbon (C) are in C6H12O6?

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There are 6 carbon atoms in C6H12O6.

Front

What is a chemical formula?

Back

A chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound.

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What does the term 'molecule' refer to?

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A molecule is a group of two or more atoms bonded together, representing the smallest fundamental unit of a chemical compound.