Elemental phosphorus exists as molecules of P4. P4 combines with chlorine gas (Cl2) to form phosphorus pentachloride, according to the following unbalanced reaction:
P4 + Cl2 → PCl5
If 16.75 grams of P4 reacts completely to form PCl5, what is the percent yield for this reaction if 85.65 grams of PCl5 is formed?
NOTE: molar masses: P4 123.88 g/mol; PCl5 208.22 g/mol Your answer must include the percent sign (%) and contain the correct number of significant figures.

percentage yield = 76.06%

Explanation:

The reaction is between phosphorus molecule and chlorine molecule to form phosphorus pentachloride.

The chemical equation can be written as follows:

P4 + Cl2 → PCl5

The equation must be balanced to solve this problem

Balanced equation

P4 + 10Cl2 → 4PCl5

molar mass of P4 = 123. 88g/mol

molar mass of PCl5 = 208.22 g/mol

From the chemical reaction 1 mole of P4 produces 4 moles of PCl5

Therefore,

1 mole of P4 = 123. 88 g

4 mole of  PCl5 = 4 × 208.22  = 832.88 grams

So,

if 123.88 g of P4 produces 832.88 g of PCl5

16.75 g of P4 will produce ? grams of PCl5

cross multiply

Theoretical yield of  the reaction = (16.75 × 832.88)/123.88

Theoretical yield of  the reaction = 13950.74/123.88

Theoretical yield of  the reaction = 112.61494995

Theoretical yield of  the reaction = 112.61494995 g

percentage yield = actual yield/theoretical yield × 100

percentage yield = 85. 65/112.61494995 × 100

percentage yield = 8565/112.61494995

percentage yield = 76.055621423

percentage yield = 76.06%

The percent yield of this reaction is 76.07 %

Explanation:

Step 1: data given

Mass of P4 = 16.75 grams

MAss of PCL5 = 85.65 grams

Molar mass P4 = 123.88 g/mol

PCl5 = 208.22 g/mol

Step 2: The balanced equation

P4 + 10Cl2 → 4PCl5

Step 3: Calculate moles of P4

Moles P4 = mass P4 / molar mass P4

Moles P4 = 16.75 grams / 123.88 g/mol

Moles P4 = 0.1352 moles

Step 4: Calculate moles PCl5

For 1 mol P4 we need 10 moles Cl2 to produce 4 moles PCl5

For 0.1352 moles P4 we'll have 4*0.1352  = 0.5408 moles PCl5

Step 5: Calculate mass PCl5

Mass PCl5 = moles PCl5 * molar mass PCl5

Mass PCl5 = 0.5408 moles * 208.22 g/mol

Mass PCl5 = 112.6 grams

Step 6: Calculate the percent yield

Percent yield = (actual yileld / theoretical yield ) * 100 %

Percent yield = ( 85.65 grams / 112.6 grams ) *100%

Percent yield = 76.07 %

The percent yield of this reaction is 76.07 %

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.