Use the periodic table to identify the molar mass of each element below. Answer without doing any calculations.

Answer:

The empirical formula is =

The Valproic acid formula is =

Explanation:

Mass of the produced water = 0.166 g

Molar mass of water = 18 g/mol

The moles of are calculated as 0.166 g /18 g/mol = 0.00922 moles.

In 1 mole of water, there are 2 moles of hydrogen atoms.

Thus,

Moles of H = 2 x 0.00922 = 0.01844 moles

Each hydrogen atom's molar mass is 1.008 g/mol.

Hydrogen mass in the molecule = 0.01844 x 1.008 = 0.018588 g

Mass of produced carbon dioxide = 0.403 g

Molar mass of carbon dioxide = 44.01 g/mol

The moles of are calculated as 0.403 g  /44.01 g/mol = 0.009157 moles.

Each carbon atom's presence is 1 mole in 1 mole of carbon dioxide.

So,

Moles of C = 0.009157 moles

The molar mass of carbon is 12.0107 g/mol.

Carbon mass in molecule = 0.009157 x 12.0107 = 0.11 g

Since Valproic acid comprises only hydrogen, oxygen, and carbon, the oxygen mass in the sample = Total mass - Carbon mass  - Hydrogen mass.

The sample's overall mass = 0.165 g.

Oxygen mass in the sample = 0.165 - 0.11 - 0.018588 = 0.036412 g  

The molar mass of oxygen is 15.999 g/mol.

Moles of O  = 0.036412  / 15.999  = 0.002276 moles

Taking the simplest ratio for H, O, and C yields:

0.01844: 0.002276: 0.009157

= 8: 1: 4

The empirical formula becomes

While molecular formulas detail the precise count of atoms for each element, empirical formulas represent the simplest form or reduced ratio of these elements in the compound.

Consequently,  

The molecular mass equals n × Empirical mass.

Here, n is a positive integer from 1, 2, 3...

Empirical mass = 4×12 + 8×1 + 16 = 72 g/mol.

Molar mass = 144 g/mol.

Thus,  

The molecular mass = n × Empirical mass.

144 = n × 72

⇒ n = 2

The Valproic acid formula is =

Response:

The mass percentage of a solution comprising 7.6 grams of sucrose and 83.4 grams of water equals 8.351 %.

Details:

Provided data:

Sucrose mass = 7.6 grams

Water mass = 83.4 grams

In this scenario, sucrose acts as the solute, while water is the solvent.

The calculation for mass percent of a solution is done using the following formula:

Mass percent = (Mass of Solute/Mass of Solution)(100)

As sucrose is the solute, the mass equals 7.6 grams.

The total mass of the solution, which includes both sucrose and water, comes out to:

Total mass = 7.6 grams + 83.4 grams = 91 grams

Therefore, applying the values gives mass percent = (7.6/91)(100) = 8.351 %.

Step 1: Convert density from g/mL to g/L; 0.807 g/mL is equivalent to 807 g/L. Step 2: Calculate Moles of N₂; Density = Mass / Volume, or Mass = Density × Volume. Plugging in values, Mass = 807 g/L × 1 L gives us Mass = 807 g. Similarly, Moles = Mass / M.mass, which leads to Moles = 807 g / 28 g.mol⁻¹, giving us Moles = 28.82 moles. Step 3: Apply the Ideal Gas Law to determine Volume of gas occupied; P V = n R T, thus V = n R T / P. Remember to convert temperature to Kelvin (25 °C + 273 = 298 K). Hence, V = (28.82 mol × 0.08206 atm.L.mol⁻¹.K⁻¹ × 298 K) ÷ 1 atm, resulting in V = 704.76 L.

For instance, what is the difference in electronegativity for Acetone(CH2O)? Are there two distinct values, namely 0.4 for C versus H and 1.0 for C versus O? How do you decide which one to adopt?

6 Comments

AlwaysReady1

•

Apr 3, 2016, 10:14 PM

I may not fully grasp the question, but if you’re seeking to determine a compound's electronegativity to assess its electron-attracting capability, there are various other influencing factors.

It varies depending on the compound. For example, CH2O, known as formaldehyde, has oxygen with two pairs of electrons that can be donated. Neither hydrogen nor carbon can bond further as they are already fulfilling their valence shell requirements.

Robo94

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You're attempting to apply a concept from a binary system to a more complex one. I assume you're aiming to figure out a molecule's dipole moment. In the case of a diatomic molecule (where A is bonded to B), the potential difference can simply be determined as A minus B. For larger molecules, the calculations become much more involved.

If this inquiry is related to homework assistance, it’s a distinctly different method from what you might be accustomed to. I recommend starting with water and then expanding out from there.

Check this out: https://www.khanacademy.org/science/organic-chemistry/gen-chem-review/electronegativity-polarity/v/dipole-moment

Philosoaxolotl

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Electronegativity pertains to single elements (or rather individual atoms) and lacks straightforward applicability to broader molecules.

What precisely are you aiming to do with this data? If you're delving into how electrons transition between molecules, the situation is more intricate—within a molecule, the more electronegative elements pull electrons from other atoms (which frequently happens in organic compounds, such as when oxygen bonds with carbon and pulls in some of its electrons). Nevertheless, this effect diminishes in lengthened molecules. The system is more complicated as molecules do not possess a single, constant electronegativity (which is more accurate for atoms); instead, they exhibit varied localized charge regions that will respond differently.

From what I gather, your question pertains to the electronegativity difference among the atoms within an acetone molecule. This indeed relies on which two atoms you are examining and won't remain constant throughout; however, the difference won't simply match the values listed in an electronegativity table due to the factors discussed earlier.

This explanation might seem a bit hazy, and I’m just an undergraduate, so please take my interpretation lightly, but I am open to clarifying further if needed.

cheeseborito

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That statement is inaccurate.

Electronegativity represents the attraction an atom holds for the electrons in a covalent bond with another atom. Essentially, an element does not have a singular electronegativity; it fluctuates based on its bonding partners. We cannot discuss the electronegativity of an atom in isolation.

While average values are useful for practical discussions (though they may not capture the nuance), the effective electronegativity of an oxygen atom bonded to carbon will remain fairly consistent.

As far as my understanding goes, even though my definition of electronegativity may lack precision, the influence an oxygen atom has on the electrons of a carbon atom is affected by what the carbon is bonded to. For instance, the local charge around the oxygen in acetic acid will be more pronounced than that in decanoic acid.

I may have phrased the electronegativity issue poorly—what I meant was the interaction between pairs of atoms as related to one another. An oxygen will exert a consistent pull regarding a carbon atom, but the changes in local charge can differ due to the influence of surrounding atoms, making the topics we typically utilize electronegativity to clarify substantially more intricate.

Result:

I believe it’s called Trinitrogen Pentaseleniumide

Explanation:

Tri means three

Penta means five

The second element concludes with -ide