Part A How many O2 molecules are needed to react with 3.95g of S? Part B What is

Question

Part A

How many O2 molecules are needed to react with 3.95g of S?

Part B

What is the theoretical yield of SO3 produced by the quantities described in Part A?

Express your answer numerically in grams.

Limiting reactant

Next, consider a situation in which all of the S is consumed before all of the O2 reacts, or one in which you have excess S because all of the O2 has been used up.

Part C

For each of the given situations, indicate whether S or O2 is the limiting reactant.

Drag each item to the appropriate bin.

PART D

What is the concentration of K+ in 0.15 M of K2S?

PART E

A scientist wants to make a solution of tribasic sodium phosphate, Na3PO4, for a laboratory experiment. How many grams of Na3PO4 will be needed to produce 500mL of a solution that has a concentration of Na+ ions of 1.10M ?

Express your answer to three significant figures and include the appropriate units.

Question 2

When solutions of silver nitrate and potassium chloride are mixed, silver chloride precipitates out of solution according to the equation

AgNO3(aq)+KCl(aq)?AgCl(s)+KNO3(aq)

Part A

What mass of silver chloride can be produced from 1.86L of a 0.130M solution of silver nitrate?

Express your answer with the appropriate units.

Part B

The reaction described in Part A required 3.80L of potassium chloride. What is the concentration of this potassium chloride solution?

PART C

The chemical 5-amino-2,3-dihydro-1,4-phthalazinedione, better known as luminol, is used by forensic scientists in analyzing crime scenes for the presence of washed-away blood. Luminol is so sensitive that it can detect blood that has been diluted 10,000 times. A basic solution of luminol is often sprayed onto surfaces that are suspected of containing minute amounts of blood.

Luminol has a molecular weight of 177 g/mol.

Part C

The forensic technician at a crime scene has just prepared a luminol stock solution by adding 20.0gof luminol into a total volume of 75.0 mL of H2O.

What is the molarity of the stock solution of luminol?

Express your answer with the appropriate units.

Part D

Before investigating the scene, the technician must dilute the luminol solution to a concentration of 3.00

PART D

What is the concentration of K+ in 0.15 M of K2S?

Explanation / Answer

Part a)3O2+2S --> 2SO3

Number of moles of sulper=3.95/32=0.1234moles

O2 required=0.1234*3/2=0.185 mole=0.185*6.023*10^23 molecules=1.115*10^23 molecules

part b)theoretical yield of SO3 produced =0.1234 mole

Part C)

situation in which all of the S is consumed before all of the O2 reacts S is limiting reagent and O2 is excess reagent

Part D)

concentration of K+ in 0.15 M of K2S is 0.3M

Part E)

Number of moles of Na3PO4 required=1.1/3

Number of grams of Na3PO4=1.1*164/3=60.1 grams

Question 2)

Part A)

1.86L of a 0.130M solution of silver nitrate contains 1.86*0.13 grams of silver nitrate=0.2418 grams

                                                         =0.2418/170 moles=1.42 milli moles

This produces 1.42 millimoles of AgCl=1.42*10^-3*143.32 grams =0.203 grams

Part B) 1.42 mole of KCl is required .So concentration of KCl is 1.42/3.6 M=0.394 M

Part C)Molarity=mass/(molecular weight*volume)=20/(177*75*10^-3) =1.5M

Part D)number of moles of luminol are present in 2.00 L of the diluted spray=2*3*10^-2=0.06 mole

Part E)zinc chloride molecular weight=136.315

molarity of ZnCl2 that forms when 30.0g of zinc completely reacts with CuCl2=30/(136.315*270*10^-3)=0.815M

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