Problem 51 - Chemistry The Central Science In Si Units

Question

How many hydrogen atoms are in each of the following: (a) \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\) (b) \(\mathrm{Ca}\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{COO}\right)_{2}\) (c) \(\left(\mathrm{NH}_{4}\right)_{3} \mathrm{PO}_{4} ?\)

Step-by-Step Solution

Answer

(a) 6 H atoms, (b) 10 H atoms, (c) 12 H atoms.

Step 1: Determine Hydrogen Atoms in Ethanol

For \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\), which is ethanol, we have 5 hydrogen atoms in \(\mathrm{C}_{2} \mathrm{H}_{5}\) and 1 hydrogen in the \(\mathrm{OH}\) group. Thus, total hydrogen atoms can be calculated as: \[5 + 1 = 6\].

Step 2: Calculate Hydrogen Atoms in Calcium Butanoate

In \(\mathrm{Ca}\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{COO}\right)_{2}\), the \(\mathrm{C}_{2} \mathrm{H}_{5}\) part of each butanoate ion has 5 hydrogen atoms. Since there are 2 such groups due to the subscript outside, the total is \[5 \times 2 = 10\] hydrogen atoms.

Step 3: Analyze Hydrogen Composition in Ammonium Phosphate

For \(\left(\mathrm{NH}_{4}\right)_{3} \mathrm{PO}_{4}\), the \(\mathrm{NH}_{4}\) means each ammonium ion contains 4 hydrogen atoms. Given the subscript \(3\) indicates there are 3 ammonium ions, the total hydrogen atoms are \[4 \times 3 = 12\].

Key Concepts

Molecular Formula Analysis

Molecular formulas are like the secret code of chemistry. They tell you what atoms make up a molecule and how many of each are present. For example, let's consider ethanol, \( \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH} \). This formula reveals that ethanol contains two carbon (\( \mathrm{C} \)) atoms, six hydrogen (\( \mathrm{H} \)) atoms, and one oxygen (\( \mathrm{O} \)) atom. Understanding a molecular formula allows chemists to decipher the chemical structure of a compound.
To analyze a molecular formula, follow these steps:

• Identify the chemical symbols, such as \( \mathrm{C} \), \( \mathrm{H} \), \( \mathrm{O} \), which represent the elements.
• Use the numbers written as subscripts to determine how many atoms of each element are in the molecule.

Analyzing molecular formulas is a fundamental skill in chemistry that provides the blueprint of the compound's structure.

Hydrogen Atoms Count

Counting the number of hydrogen atoms in a chemical compound is essential for understanding its properties and reactivity. Hydrogen, being the lightest and most abundant element in the universe, plays a crucial role in forming compounds.
Let's break this down with examples:

• In ethanol, \( \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH} \), the molecular formula shows that there are six hydrogen atoms in total (five from \( \mathrm{C}_{2} \mathrm{H}_{5} \) plus one more from \( \mathrm{OH} \)).
• For calcium butanoate, \( \mathrm{Ca}\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{COO}\right)_{2} \), each \( \mathrm{C}_{2} \mathrm{H}_{5} \) group contains five hydrogen atoms. Since there are two such groups, the total is ten hydrogen atoms.
• In ammonium phosphate, \( \left(\mathrm{NH}_{4}\right)_{3} \mathrm{PO}_{4} \), each \( \mathrm{NH}_{4} \) ion has four hydrogen atoms. With three ammonium ions present, you get a total of twelve hydrogen atoms.

Understanding how hydrogen atoms are distributed within molecules aids in predicting chemical behavior.

Chemical Compound Analysis

Chemical compound analysis involves breaking down a compound into its basic components to understand its structure and properties. It's the process of deciphering a complex formula to make it simpler and clearer.

• Each compound, like molecules or salts, is made of atoms bonded together. The formula reveals how these atoms are grouped.
• The process starts with identifying the elements, then counting each type of atom using subscripts to ensure the compound adheres to its chemical identity.

For instance, in analyzing calcium butanoate, \( \mathrm{Ca}\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{COO}\right)_{2} \), you notice there's one calcium atom, but two \( \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{COO} \) groups.
This informs us about the "2-to-1" ratio of butanoate ions to calcium ions.
By examining the molecular formula, chemists can infer not just the ratio of the ions but also extrapolate the interaction and bonding patterns in the molecule. This analysis ultimately helps in predicting how the compound will react under different conditions and is central to fields like pharmacology, materials science, and environmental chemistry.