PLEASE EXPLAIN CLEARLY STEP BY STEP TO RECEIVE THE POINTS THANKS. 1) Organic che

Question

PLEASE EXPLAIN CLEARLY STEP BY STEP TO RECEIVE THE POINTS

THANKS.

1) Organic chemists write the formula for dimethyl ether as CH3OCH3. A sample of dimethyl ether contains 0.794 mole oxygen. How many moles of carbon are in the sample?

2) For the combustion of one mole of butane, C4H10, how many moles of oxygen gas are required?

3) For the reaction 2 KI(s) + Cl2(g) ? 2 KCl(s) + I2(s), if you start with 30.0 grams of KI (MM = 166.0g/mol) and 15.0 grams of Cl2 (MM = 70.9g/mol) how many grams of the each reactant will be left assuming 100% yield of product?

4) A polymer is formed by bonding 300 identical molecules, called the monomer, one to another in a chain. The empirical formula for the polymer is CH2. If the molar mass of the polymer is 12,600g/mol, what is the molecular formula of the monomer? Assume there is no other product than the polymer when it is synthesized from the monomer.

5) A sample of an unknown acid that weighs 2.374 g is placed in a 1.000 L volumetric flask and diluted to the mark with distilled water. A 25.0 mL volume of this solution is titrated to the equivalence point with 18.3 mL of 0.120 M NaOH. What is the molar mass of the unknown acid?

6) If there are only 2 naturally occurring isotopes of silver with the most abundant being Ag-107 (106.905 amu) at 51.8% abundance, what is the other naturally occurring isotope?

Explanation / Answer

1.) one mole of CH3OCH3 contains 1 mole of O and 2 moles of C

So moles of carbon in sample = 2*0.794 = 1.588

2.) 2 C4H10 + 13 O2 ===> 8 CO2 + 10 H2O

C4H10 + 13/2 O2 ===> 4 CO2 + 5 H2O

So, you need 6.5 moles of oxygen gas (the diatomic molecule)

3.) 2 KI(s) + Cl2(g) -> 2 KCl(s) + I2(s)

moles of KI = 30/166 = 0.181

moles of Cl2 = 15/70.9 = 0.212

Here limiting reagent is Cl2

So moles of Cl2 left = 0.212 - (0.5*0.181) = 0.121

So grams of Cl2 left = 8.58 grams

4.) molar mass of CH2 = 14 g

So no .of CH2 in polymer = 12600/14 = 900

So molecular formula of polymer = (CH2)90 = C90H180

5.) M1*V1 = M2*V2

18.3*0.12 = (2.374/M)*25

So M = 27.03 grams

So molar mass of unknown acid = 27.03 grams

6.) Naturally occurring silver (Ag) is composed of the two stable isotopes 107Ag and 109Ag with 107Ag being the more abundant (51.839% natural abundance)

So the other isotope is Ag-109 with 48.1% abundance

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