Determining the Empirical Formula from a Percent

Mr. Causey
20 Jul 201203:39
EducationalLearning
32 Likes 10 Comments

TLDRIn this 'Problem of the Week' video, Mr. Cozzi guides viewers through determining the empirical formula of a molecule containing 47.35% carbon, 10.60% hydrogen, and 42.05% oxygen. He explains the process of converting percentages to grams, then to moles, and finally to ratios to find the empirical formula. By using the molar masses from the periodic table, he calculates moles for each element and simplifies the ratios to find the formula C3H8O. He encourages viewers to reach out with questions and to subscribe to his YouTube channel for more educational content.

Takeaways
  • 🔍 The video is a 'Problem of the Week' series by Mr. Cozzi, focusing on empirical formulas.
  • 📚 Viewers are reminded to have a calculator, periodic table, and knowledge of empirical formulas, moles, and molar mass handy.
  • 🧪 The problem involves determining the empirical formula of a molecule with given percentages of carbon, hydrogen, and oxygen.
  • 📉 The first step is to convert the given percentages to grams, assuming a 100-gram sample of the compound.
  • ⚖️ The masses of carbon, hydrogen, and oxygen are calculated to be 47.35g, 10.60g, and 42.05g respectively.
  • 🔢 The next step is to convert these masses to moles using the molar masses from the periodic table.
  • 📈 Mr. Cozzi demonstrates the conversion to moles, resulting in 3.943 moles of carbon, 10.50 moles of hydrogen, and 2.628 moles of oxygen.
  • 📊 To find the empirical formula, the smallest value in moles is identified, and all values are divided by this number to find ratios.
  • 🔄 A problem arises with non-whole number ratios, which is resolved by multiplying all values by two to achieve whole numbers.
  • 📝 The final empirical formula derived is C3H8O, after adjusting the ratios to whole numbers.
  • 💌 Mr. Cozzi invites viewers to contact him with questions via email and to subscribe to his YouTube channel for more content.
  • 🌐 The video script also mentions visiting Mr. Cozzi's website and signing up for his Facebook group.
Q & A

  • What is the main topic of Mr. Cozzi's 'Problem of the Week' video?

    -The main topic of the video is determining the empirical formula of a compound based on its elemental composition.

  • What are the prerequisites for solving the problem presented in the video?

    -The prerequisites include knowledge of empirical formulas, the periodic table, moles, molar mass, and the ability to use a calculator.

  • What is the elemental composition of the molecule in the problem, in terms of percentages?

    -The molecule contains 47.35% carbon, 10.60% hydrogen, and 42.05% oxygen.

  • How does Mr. Cozzi suggest converting percentages to grams for the calculation?

    -He suggests assuming you have 100 grams of the compound and then converting the percentages to grams based on this assumption.

  • What is the molar mass of carbon, and how is it used in the calculation?

    -The molar mass of carbon is approximately 12.01 g/mol. It is used to convert the grams of carbon to moles.

  • How many moles of carbon, hydrogen, and oxygen are there in 100 grams of the compound according to the video?

    -There are 3.943 moles of carbon, 10.50 moles of hydrogen, and 2.628 moles of oxygen.

  • What is the purpose of dividing the moles of each element by the smallest value?

    -The purpose is to find the simplest whole number ratio of the elements to determine the empirical formula.

  • What is the smallest value in moles among the elements in the compound, and what does it represent?

    -The smallest value is 2.628 moles of oxygen, which represents the basis for the ratio of the elements in the compound.

  • How does Mr. Cozzi resolve the issue of non-whole number ratios in the empirical formula?

    -He suggests multiplying all the values by two to achieve whole numbers, resulting in a ratio of 3 carbons, 8 hydrogens, and 4 oxygens.

  • What is the empirical formula of the compound as determined in the video?

    -The empirical formula of the compound is C3H8O.

  • How can viewers get in touch with Mr. Cozzi or follow his work?

    -Viewers can email Mr. Cozzi at mr.cozzi@mrcozzi.com, visit his website at mrcozziworld.com, and subscribe to his YouTube channel.

Outlines
00:00
🔍 Problem Introduction and Empirical Formula Challenge

Mr. Cozzi introduces a chemistry problem of the week focused on determining the empirical formula of a compound. The problem requires knowledge of empirical formulas, moles, molar mass, and the use of a calculator and periodic table. The compound in question contains 47.35% carbon, 10.60% hydrogen, and 42.05% oxygen by mass. The process involves converting percentages to grams, then to moles, and finally to ratios to find the empirical formula. An example calculation is provided, assuming 100 grams of the compound.

Mindmap
Keywords
💡Empirical Formula
An empirical formula is the simplest whole-number ratio of atoms of each element in a compound. In the video, the empirical formula is derived by converting percentages to grams, then to moles, and finally to ratios to determine the simplest whole-number ratio of carbon, hydrogen, and oxygen in the given compound.
💡Calculator
A calculator is an electronic device used to perform arithmetic operations. In the context of the video, the calculator is necessary for converting percentages to grams, calculating molar masses, and determining moles of elements, which are all steps in finding the empirical formula.
💡Periodic Table
The periodic table is a tabular arrangement of the chemical elements, ordered by their atomic number, electron configuration, and recurring chemical properties. It is referenced in the video to find the molar masses of carbon, hydrogen, and oxygen, which are essential for converting grams to moles.
💡Moles
Moles are a measure used in chemistry to express amounts of a chemical substance, defined as the number of atoms in 12 grams of carbon-12. In the video, moles are calculated by dividing the mass of each element by its molar mass to determine the ratio of atoms in the empirical formula.
💡Molar Mass
Molar mass is the mass of one mole of a substance, typically measured in grams per mole (g/mol). It is used in the video to convert the given percentages of elements in the compound to moles, which is a crucial step in determining the empirical formula.
💡Percentages
Percentages are a way to express a proportion or a fraction of a whole, in this case, the composition of the compound by mass. The video starts with converting the given percentages of carbon, hydrogen, and oxygen to grams, which is the first step in finding the empirical formula.
💡Ratios
Ratios are the relative values of quantities, often expressed as a fraction or a multiple. In the video, the moles of each element are converted to ratios to find the simplest whole-number ratio, which is used to determine the empirical formula.
💡Compound
A compound is a substance formed when two or more chemical elements are chemically bonded together. The video's problem involves analyzing a compound containing carbon, hydrogen, and oxygen to find its empirical formula.
💡Blackboard
A blackboard is traditionally used in educational settings to write and display information. In the script, the blackboard is mentioned as the place where the masses of elements are written down and converted to moles, aiding in the calculation of the empirical formula.
💡Whole Numbers
Whole numbers are integers without any fractional or decimal parts. The video emphasizes the need to have whole numbers in the empirical formula, which is achieved by adjusting the ratios of moles to the smallest value and then scaling up to the nearest whole numbers.
💡Mr. Cozzi
Mr. Cozzi is the presenter of the video, introducing the problem of the week and guiding the viewers through the process of finding the empirical formula. His name is used to personalize the content and establish a connection with the audience.
Highlights

Introduction to the problem of the week involving empirical formulas.

Requirement of calculator, periodic table, and knowledge of empirical formulas, moles, and molar mass.

Problem statement: Determining the empirical formula of a molecule with given percentages of carbon, hydrogen, and oxygen.

Conversion of percentages to grams assuming 100 grams of the compound.

Mass of carbon, hydrogen, and oxygen calculated to be 47.35g, 10.60g, and 42.05g respectively.

Explanation of converting masses to moles using molar mass from the periodic table.

Calculation of moles for carbon, hydrogen, and oxygen based on their masses.

Identification of the smallest value in moles for ratio determination.

Division of moles of carbon and hydrogen by the moles of oxygen to find ratios.

Adjustment of ratios to achieve whole numbers by multiplying by two.

Determination of the empirical formula C3H8O based on the adjusted ratios.

Emphasis on the process of converting grams to moles and determining ratios for the empirical formula.

Invitation for questions and contact information for Mr. Cozzi.

Promotion of Mr. Cozzi's website and YouTube channel for further educational content.

Mention of a Facebook group sign-up available on the YouTube channel.

Encouragement for viewers to subscribe to the YouTube channel for more educational videos.

Transcripts

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Empirical FormulaChemistry ProblemMolar MassMoles CalculationPeriodic TableChemistry TutorialEducational ContentScience LearningMr. CozziYouTube Channel