Chemistry, 08.10.2020 03:01 diegomacias2411

A student wants to burn a 1.25 mL sample of ethanol (C2H5OH, d = 0.789 g/mL) in a jar containing dry air. Assuming the air in the jar is at standard atmospheric pressure and room temperature (22 °C), what volume will the jar need to be in order to hold enough oxygen for complete combustion? Hint: Refer to the composition of dry air in the previous question. (a) Write a balanced chemical reaction for the combustion of ethanol. (b) Calculate the moles of oxygen needed to completely combust the ethanol. (c) Calculate the partial pressure of oxygen in the jar. (d) Calculate the volume of oxygen (in L) needed in t

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Answer from: MaeWolfe

The volume of the jar needed in order to hold enough oxygen for complete combustion is 24.2 L

(a) C₂H₅OH + 2O₂ -------> 2CO₂ + 3H₂O

(b) The moles of oxygen needed to completely combust the ethanol is 0.0429 moles

(d) the volume of oxygen (in L) needed in the jar is 1.038 L

Explanation:

Given;

volume of ethanol, V = 1.25 mL

density of ethanol, ρ = 0.789 g/mL

mass of ethanol, m = ρV = (1.25 mL) x (0.789 g/mL) = 0.986g

The volume of the dry air is calculated as;

$P_d = \rho _d R_d T\\\\P_d = (\frac{M_d}{V_d} )R_d T\\\\V_d = (\frac{M_d}{P_d} )R_d T\\\\V_d = (\frac{0.02897 \ (kg)}{101325 \ (Pa)} )*287 \ (J/K.kg)* 295\ (K)\\\\V_d = 0.0242 \ m^3\\\\V_d = 24.2 \ L$

(a) a balanced chemical reaction for the combustion of ethanol

C₂H₅OH + 2O₂ -------> 2CO₂ + 3H₂O

(b) The moles of oxygen needed to completely combust the ethanol.

$=0.986 g \ C_2H_5OH *(\frac{1 \ mol \ C_2H_5OH}{46g \ C_2H_5OH} )*(\frac{2 \ Mol \ O_2}{1 \ mol \ C_2H_5OH} )\\\\ = 0.0429 \ mols.$

Total pressure of air in the jar, Pt = 101,325 Pa

Partial pressure of oxygen = nPt

= 0.0429 x 101,325 Pa = 4346.84 Pa

(d) the volume of oxygen (in L) needed in the jar

Total volume of air in the jar = 24.2 L

The fraction of this volume by oxygen = 0.0429 mols x 24.2 L = 1.038 L

Answer from: Quest

For cyclohexane compounds drawn in a chair conformation: -axial bonds are vertical -equatorial bonds are parallel to two bonds within the ring. thus, as i assume the chair conformation is drawn: -the x group is in an axial position, as are the five other vertical bonds. -three axial bonds are on the top face of the ring -the other three axial bonds are on the bottom face the position of the second substituent on each ring carbon is equatorial. gauche groups must be on an adjacent carbon such as carbon 6 and carbon 2, and also gauche groups are rotated by 60 degrees relative to each other. drawing the newman projections for c1–c2 and c1–c6 aids in visualizing the groups that are gauche to the y group on c1. click this link and watch some academic videos that may you more understand the topic

Answer from: Quest

2b2t

explanation:

2b2t

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A student wants to burn a 1.25 mL sample of ethanol (C2H5OH, d = 0.789 g/mL) in a jar containing dry...

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