Chapter 7: Problem 94
Compound \(\mathrm{X}\) requires \(104 \mathrm{~g}\) of \(\mathrm{O}_{2}\) to produce 2 moles of \(\mathrm{CO}_{2}\) and \(2.5\) moles of \(\mathrm{H}_{2} \mathrm{O}\). (a) What is the empirical formula for X? (b) What additional information would you need to determine the molecular formula for \(\mathrm{X}\) ?
Short Answer
Step by step solution
- Determine moles of Oxygen (O) from given mass
- Calculate moles of elements in given products
- Calculate moles of Oxygen from products
- Determine moles of oxygen in compound X
- Derive the empirical formula for X
- Scale for Whole Numbers for empirical formula
- Determine information needed for molecular formula
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Moles Calculation
When converting mass to moles, use the formula: \text{Moles} = \frac{\text{Mass of substance (g)}}{\text{Molar mass (g/mol)}}\.
Let's consider the above problem, where 104 grams of \(\text{O}_2\) are provided. Given that the molar mass of \(\text{O}_2\) is 32 g/mol, the calculation will be:
\text{Moles of } \text{O}_2 = \frac{104 \text{ g}}{32 \text{ g/mol}} = 3.25 \text{ moles}\.
By performing this calculation, we are able to know how much \(\text{O}_2\) is present in terms of moles, making further calculations more manageable.
Stoichiometry
In our provided exercise, we need to find the empirical formula of compound \(\text{X}\). The empirical formula is the simplest whole number ratio of the elements in a compound. By identifying the moles of each element present in the products, we can derive this ratio.
Step by step, we determine:
- 2 moles of \(\text{CO}_2\) yield 2 moles of Carbon (C).
- 2.5 moles of \(\text{H}_2\text{O}\) yield 5 moles of Hydrogen (H).
- Combining the results: 2 moles of C, 5 moles of H, and according to the provided oxygen data, we need 6.5 moles of O in total from products.
Subtracting and adjusting by whole numbers allows us to form the ratio and therefore the empirical formula: \(\text{CH}_{1.25}\text{O}\), which simplifies as we consider the nearest whole numbers to \(C_4H_5O\).
Molar Mass
In the exercise, the empirical formula of compound \(\text{X}\) was found to be \(\text{C}_4\text{H}_5\text{O}\). To convert this to a molecular formula, one would need additional information about the molar mass of compound \(\text{X}\).
Suppose the molar mass of compound \(\text{X}\) is known. We compare it with the empirical formula's molar mass. For instance, if the given molar mass of \(\text{X}\) is twice the empirical formula mass, then the molecular formula is double the empirical formula units, resulting in \(\text{C}_8\text{H}_{10}\text{O}_2\).
Therefore, understanding molar mass is essential for converting empirical formulas into the molecular formulas.