Textbook Question
Suppose you have 3.00 g of powdered zinc metal, 3.00g of powdered silver metal and 500.0 mL of a 0.2 M copper(II) nitrate solution. (b) What is the net ionic equation that describes this reaction?
Ch.4 - Reactions in Aqueous Solution
Chapter 4, Problem 106b
(b) An elemental analysis of the acid indicates that it is composed of 5.89% H, 70.6% C, and 23.5% O by mass. What is its molecular formula?
Verified step by step guidance1
Step 1: Assume that you have 100 g of the compound. This means that you have 5.89 g of Hydrogen (H), 70.6 g of Carbon (C), and 23.5 g of Oxygen (O).
Step 2: Convert these masses into moles using the molar mass of each element. The molar mass of H is approximately 1 g/mol, the molar mass of C is approximately 12 g/mol, and the molar mass of O is approximately 16 g/mol.
Step 3: Divide each mole value by the smallest number of moles calculated. This will give you the mole ratio of H, C, and O in the compound.
Step 4: If the mole ratios are not whole numbers, multiply them by the smallest number that will convert them all to whole numbers. This will give you the empirical formula of the compound.
Step 5: To find the molecular formula, you need to know the molar mass of the compound. Divide the molar mass of the compound by the molar mass of the empirical formula. This will give you a whole number, which you multiply by the subscripts in the empirical formula to get the molecular formula.
Recommended similar problem, with video answer:
Verified Solution
This video solution was recommended by our tutors as helpful for the problem above
Video duration:
5mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Empirical Formula
The empirical formula represents the simplest whole-number ratio of the elements in a compound. To determine the empirical formula from percentage composition, one converts the percentages to moles by dividing by the atomic masses of the elements. This ratio helps in identifying the basic composition of the compound before determining the molecular formula.
Recommended video:
Guided course
02:26
Empirical vs Molecular Formula
Molecular Formula
The molecular formula indicates the actual number of atoms of each element in a molecule of a compound. It can be derived from the empirical formula by multiplying it by a whole number, which is determined by comparing the molar mass of the compound to the molar mass of the empirical formula. This formula provides more specific information about the compound's structure.
Recommended video:
Guided course
02:08Determining Molecular Formulas
Molar Mass Calculation
Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). To find the molecular formula, one must first calculate the molar mass of the compound using the atomic masses of its constituent elements. This value is essential for determining the relationship between the empirical and molecular formulas.
Recommended video:
Guided course
03:12Molar Mass Calculation Example
Related Practice
Textbook Question
Suppose you have 3.00 g of powdered zinc metal, 3.00g of powdered silver metal and 500.0 mL of a 0.2 M copper(II) nitrate solution. (d) What is the molarity of Cu2+ ions in the resulting solution?
352
views
Textbook Question
(a) By titration, 15.0 mL of 0.1008 M sodium hydroxide is needed to neutralize a 0.2053-g sample of a weak acid. What is the molar mass of the acid if it is monoprotic?
1329
views
Textbook Question
The discovery of hafnium, element number 72, provided
a controversial episode in chemistry. G. Urbain, a French
chemist, claimed in 1911 to have isolated an element
number 72 from a sample of rare earth (elements 58–71)
compounds. However, Niels Bohr believed that hafnium
was more likely to be found along with zirconium than
with the rare earths. D. Coster and G. von Hevesy, working
in Bohr's laboratory in Copenhagen, showed in 1922 that
element 72 was present in a sample of Norwegian zircon,
an ore of zirconium. (The name hafnium comes from the
Latin name for Copenhagen, Hafnia).
(c) Solid zirconium
dioxide, ZrO2, reacts with chlorine gas in the presence
of carbon. The products of the reaction are ZrCl4 and two
gases, CO2 and CO in the ratio 1:2. Write a balanced chemical
equation for the reaction.
655
views
Open Question
A fertilizer railroad car carrying 129,840 L of commercial aqueous ammonia (30% ammonia by mass) tips over and spills. The density of the aqueous ammonia solution is 0.88 g/cm³. What mass of citric acid, C₆H₈O₇ (which contains three acidic protons), is required to neutralize the spill?
Textbook Question
A sample of 8.69 g of Zn(OH)2 is added to 155.0 mL of 0.750 M H2SO4. (b) Which is the limiting reactant in the reaction?