Hello, I am in a college Chemistry course (General Chem 1) and looking for some

Question

Hello, I am in a college Chemistry course (General Chem 1) and looking for some assistance with the above question. If some detail could be provided (shown work) with the final answer included, I would be greatly appreciative. This is a study guide to my final exam and I am in need of understanding the questions rather than memorizing how to do them. Thank you!

(4. (12 pts) You have a sample of a compound with the molecular formula czHsx, where X is a halogen (Fr Cl, Br, or I). Combustion analysis of 2.546 g of the sample yields 1.437 g carbon dioxide and o.7355 g Water. MIM CO 44.01 g/mo MM H20 18.02 g/mol a. What is the molar mass of the compound? b. What is the identity of X? 5. (6 pts) write balanced NET loNIC reaction c for the f

Explanation / Answer

C2H5X   is formula given

CO2 mass = 1.437 g

CO2 moles = mass / Molar mass of CO2

               = ( 1.437 g / 44 g/mol) = 0.032659

C moles = 0.032659     ( 1 C gives 1CO2 on combustion)

C mass = moles x atomic mass of C

            = 0.032659 mol x 12 g/mol = 0.3919 g

H2O moles = 0.7355 g/ ( 18.015 g/mol) = 0.040827

H moles = 2 x H2O moles = 2 x 0.040827 = 0.081654

H mass = 0.081654 mol x 1g/mol = 0.081654 g

compound mass = C + H + X mass

2.546 = 0.3919 + 0.081654 + X mass

X mass = 2.07244 g

as per formula for 2C and 5 H we have 1X           ( C2H5X os given)

hence X moles = ( 1/2) C moles = ( 1/2) 0.032659 = 0.0163295

Molar mass of X = mass / Moles of X

                  = 2.07244 g / 0.0163295 mol

          = 126.9 g/mol

hence X is Iodine I

Molar mass of C2H5I = ( 2 x 12 ) + ( 5 x 1) + ( 126.9)   = 156 g/mol

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