Question

Calcium dihydrogen phosphate is an important fertilizer. How many atoms of hydrogen are there in ten formula units of \(\mathrm{Ca}\left(\mathrm{H}_{2} \mathrm{PO}_{4}\right)_{2}\) ?

Short answer

There are 40 hydrogen atoms in ten formula units of \(\mathrm{Ca\left( H_{2}PO_{4} \right)_{2}}\).

Step-by-step solution

Identify the Chemical Formula

The chemical formula for calcium dihydrogen phosphate is \(\mathrm{Ca\left( H_{2}PO_{4} \right)_{2}}\).

Determine the Number of Hydrogen Atoms per Formula Unit

In each formula unit of \(\mathrm{Ca\left( H_{2}PO_{4} \right)_{2}}\), there are two separate \(\mathrm{H_{2}PO_{4}}\) groups. Each \(\mathrm{H_{2}PO_{4}}\) group contains 2 atoms of hydrogen.

Calculate the Total Number of Hydrogen Atoms in One Formula Unit

Each formula unit of \(\mathrm{Ca\left( H_{2}PO_{4} \right)_{2}}\) contains \(2 \times 2 = 4\) hydrogen atoms.

Calculate the Number of Hydrogen Atoms in Ten Formula Units

To find the number of hydrogen atoms in ten formula units, multiply the number of hydrogen atoms in one formula unit by ten: \(4 \times 10 = 40\) hydrogen atoms.

Key concepts

Calcium dihydrogen phosphate

Calcium dihydrogen phosphate is a crucial compound in the agricultural sector because it's used as a fertilizer. Fertilizers help plants grow by providing essential nutrients. This specific compound contains calcium (Ca), hydrogen (H), phosphorus (P), and oxygen (O), making it a rich source of nutrients. Understanding the chemical composition of calcium dihydrogen phosphate can help in determining how it benefits plant growth.

The chemical formula for calcium dihydrogen phosphate is \(Ca(H_2PO_4)_2\). This notation reveals the elements present and their proportions. The 'Ca' indicates calcium, while 'H\textsubscript{2}PO\textsubscript{4}' represents a group containing hydrogen, phosphorus, and oxygen atoms.

chemical formula interpretation

Interpreting chemical formulas is a key skill in chemistry. A chemical formula represents the elements in a compound and the number of atoms of each element. In the formula \(Ca(H_2PO_4)_2\), we can break it down to understand its structure. The 'Ca' stands for one calcium atom.

The brackets indicate that everything inside is a group that's multiplied by a subscript outside the bracket. Here, it's \(H_2PO_4\) and the subscript '2' outside means we have two of these groups in each molecule of calcium dihydrogen phosphate.

Let's examine \(H_2PO_4\):

• \textbf{H\textsubscript{2}}: 2 hydrogen atoms
• \textbf{P}: 1 phosphorus atom
• \textbf{O\textsubscript{4}}: 4 oxygen atoms

So, \(H_2PO_4\) shows a group with 2 hydrogen, 1 phosphorus, and 4 oxygen atoms. Because the group appears twice (as indicated by the '2' outside the bracket), all these atoms double.

atom counting

Counting atoms in a compound ensures we understand the total number of each type of atom. Let's break down the calculation for hydrogen atoms in \(Ca(H_2PO_4)_2\).

Each \(H_2PO_4\) group contains 2 hydrogen atoms. Since there are two of these groups in each formula unit, we multiply the hydrogen atoms: \(2 \times 2 = 4\) hydrogen atoms per formula unit.

If we look at ten formula units, we multiply the 4 hydrogen atoms from one unit by the number of formula units:
\[ 4 \times 10 = 40 \] This gives us a total of 40 hydrogen atoms in ten formula units of calcium dihydrogen phosphate.