How many atoms of each element are in the chemical formula [tex]$Ca ( OH )_2$[/tex]?
A. 1 cakium, 1 oxygen, and 1 hydrogen
B. 1 cakium, 2 oxygen, and 2 hydrogen
C. 2 cakium, 1 oxygen, and 2 hydrogen
D. 2 cakium, 2 oxygen, and 2 hydrogen
Answer (1)
The chemical formula is C a ( O H ) 2 .
There is 1 Calcium atom.
There are 1 × 2 = 2 Oxygen atoms.
There are 1 × 2 = 2 Hydrogen atoms.
Therefore, the answer is 1 c aki u m , 2 o x y g e n , an d 2 h y d ro g e n .
Explanation
Understanding the Chemical Formula We are asked to determine the number of atoms of each element in the chemical formula C a ( O H ) 2 . This means we need to count how many Calcium (Ca), Oxygen (O), and Hydrogen (H) atoms are present in the compound.
Counting the Atoms Let's break down the formula:
Ca (Calcium): There is no subscript after Ca, which means there is only 1 Calcium atom.
(OH) (Hydroxide): The subscript 2 outside the parenthesis applies to everything inside the parenthesis. This means we have to multiply the number of Oxygen and Hydrogen atoms inside the parenthesis by 2.
O (Oxygen): Inside the parenthesis, there is one Oxygen atom. Since the subscript outside the parenthesis is 2, we have 1 × 2 = 2 Oxygen atoms.
H (Hydrogen): Inside the parenthesis, there is one Hydrogen atom. Since the subscript outside the parenthesis is 2, we have 1 × 2 = 2 Hydrogen atoms.
Final Count Therefore, in the chemical formula C a ( O H ) 2 , there is 1 Calcium atom, 2 Oxygen atoms, and 2 Hydrogen atoms.
Examples
Understanding chemical formulas is crucial in chemistry. For example, when preparing a solution of calcium hydroxide ( C a ( O H ) 2 ) for an experiment, knowing the exact number of atoms of each element helps in calculating the molar mass and determining the correct amount of the compound needed to achieve the desired concentration. This ensures accurate and reliable experimental results. Similarly, in environmental science, understanding the composition of compounds like calcium hydroxide is important for studying its role in neutralizing acidic soils or industrial waste.
