There are three different dichloroethylenes (molecular formula c2h2cl2), which we can designate x, y, and z. compound x has no dipole moment, but compound z does. compounds x and z each combine with hydrogen to give the same product: c2h2cl2(x or z) + h2 → clch2―ch2cl what are the structures of x, y, and z? be sure to include lone pair electrons. x draw structure y draw structure z draw structure

Explanation:

The three options are:

1) Both Cl in the same carbon

2) One Cl in each C and both in the same side of the double bond (cis )

2) One Cl in each C and both in the oposite sides of the double bond (trans )

Options 2 and 3 are geometrical isomers and will generate the same products, so this options will be X and Z. Therefore Y is the one described in option 1.

Now, having the two electronegative atoms (Cl) in the same side will create a dipole moment but if they are oposed, the dipole moment will be canceled. Being that said we can affirm that the option 2) is Z and the option 3) is X

In the figure you can see the structures of X, Y and Z from top to bottom.

Compound X= (E)-1,2-dichloroethene

Compound Y= 1,1-dichloroethene

Compound Z= (Z)-1,2-dichloroethene

Explanation:

In this case we will have 3 isomers which have the same formula. If we use the formula, the options we have are that the chlorides are attached to the same carbon (compound Y) or different carbons (Compounds X and Y).

Now, the problem gives a clue about compounds X and Y, hydrogenation results in the same compound (see figure) therefore the only difference between the compounds is the orientation of the Cl groups, therefore one of them it must be "E" and the other "Z" (this nomenclature should be used for alkenes, since the cis / trans nomenclature is used for other types of molecules), so the question is which is the cis isomer and which is the Isomer Z ?

The problem says that compound X has no dipole moment, therefore in compound X the Cl groups must have opposite directions such that the dipole moments of both cancel each other out. In conclusion, compound X is the isomer E, compound Y is the compound in which the Cl groups are on the same carbon and compound z is the isomer Z.

The concentration of 20.0 mL H2SO4 solution that requires 22.87 mL of a 0.158 M KOH solution to reach equivalence point is 0.0904 M. or 0.0904 moles/L

Further Explanation: Molarity   Molarity may be defined as the concentration of a solution in moles per liter. It is calculated by dividing the number of moles of a solution, n by its volume in liters, V.   That is; Molarity = n/V, where n is the number of moles and V is the volume in liters.   Therefore; when given the molarity of a solution and the volume of the solution, then we can get the number of moles, by multiplying the molarity by volume;   Number of moles = Molarity x Volume Additionally, the number of moles of a compound or an element can also be calculated by dividing the mass of the compound by its relative molecular mass.

In the question given;

The equation for the reaction is:

H2SO4 + 2KOH = K2SO4 + 2H2O

Step 1: Moles of KOH  

Number of moles = Molarity x Volume  

Molarity of KOH is 0.158 M  

Volume of KOH is 22.87 mL or 0.02287 L

Therefore;

Number of moles = 0.158 M x 0.02287 mL

                            = 0.003613 Moles of KOH  

Step 2: Moles of H2SO4

Mole ratio; from the equation, 1 mole of H2SO4 requires 2 moles of KOH

Therefore;

0.003613 moles of KOH requires  

   = 0.003613/2  

   = 0.001807 Moles  

Step 3: Molarity of H2SO4

Molarity = Number of moles / Volume  

Number of moles = 0.001807 moles  

Volume = 20 mL or 0.020 L  

Therefore;

Concentration = 0.001807/ 0.020  

                       = 0.0904 M

Hence, the concentration of the acid, H2SO4 was 0.0904 M or 0.0904 moles/L

Keywords: Molarity, Moles, Volume

Learn more about:   Molarity: Relationship between moles, molarity and volume:  

Level: High School

Subject: Chemistry

Chapter: Mole and stoichiometry equations