Science Homework Help

Hello,

I would like help with the below questions.

QUESTION 1

1. Which of the following is the correct definition for the concentration of a solution?

   		The concentration of a solution is the total amount of solute that can be dissolved before it begins to precipitate out of the solution.
   		The concentration of a solution is the amount of dissolved solute divided by the amount of the entire solution.
   		The concentration of a solution is the amount of dissolved solute divided by the temperature of the solution.
   		The concentration of a solution is the amount of solvent divided by the amount of solute in the solution.
   		The concentration of a solution is the amount of dissolved solute divided by the amount of solvent in the solution.

5 points

QUESTION 2

1. Which of the following best describes what happens as a soluble ionic compound dissolves in water?

   		The charges on individual ions become shielded by a shell of polar water molecules leading the ions to separate from one another
   		Ionic compounds react with water molecules to form three-dimensional hydrogen bonded networks that connect all the ions through a dissolved cage-like structure
   		Soluble ionic compounds precipitate out of water
   		The ionic compound reacts with the water and falls apart into individual atoms
   		The water reduces (gains electrons from) anions and oxidizes (loses electrons to) cations until all ions are neutrally charged and no longer interact with one another

6 points

QUESTION 3

1. Identify all of the ionic compounds that are soluble in water.

   NaBr

   Fe(OH)3

   Mg(C2H3O2)2

   BaSO4

   Pb(NO3)2

6 points

QUESTION 4

1. Predict whether a precipitate will form or whether there will be no reaction when aqueous solutions of the following ionic compounds are mixed.

   –A.B. CaCl2 and Na2SO4 –A.B. CaCl2 and Mg(CH3CO2)2 –A.B. CaCl2 and Pb(NO3)2 –A.B. CaCl2 and K3PO4

   A. Precipitate B. No reaction

6 points

QUESTION 5

1. Choose the correct net ionic equation for the precipitation reaction that occurs when AgNO₃(aq) is mixed with NH₄Cl(aq).

   		Ag+(aq) + NO3–(aq) + NH4+(aq) + Cl–(aq) –> AgCl(s) + NH4+(aq) + NO3–(aq)
   		AgNO3(aq) + NH4Cl(aq) –> AgCl(s)+ NH4NO3(aq)
   		Ag+(aq) + Cl– (aq) –> AgCl(s)
   		NO3–(aq) + NH4+(aq) –> NO3–(aq) + NH4+(aq)
   		Ag+(aq) +NO3–(aq) + NH4+(aq) + Cl–(aq) –> Ag+(aq) + Cl–(aq) + NH4+(aq) + NO3–(aq)

5 points

QUESTION 6

1. A student dissolves 45.1 g of MgCl₂ in water to a final volume of 215 mL. What is the concentration of the resulting solution in (w/w) % composition?Assume the density of the solution is 1.00 g/mL. Calculate your answer to three significant figures in units of (w/w) %, but only enter the number in the box, no units.

6 points

QUESTION 7

1. What is the molar concentration of a 14.9 (w/v) % NaCl solution?Enter your answer to three significant figures without units.

6 points

QUESTION 8

1. Calculate the molar concentration of a 3.9 liter solution containing 1.00 moles of dissolved MgCl₂. Give only the numerical answer in your response.

6 points

QUESTION 9

1. Given that the molar mass of penicillin is 356.37 g/mol, what is the molar concentration of an 86.9 mL aqueous solution that contains 14.2 g of solid penicillin?

6 points

QUESTION 10

1. What volume of a 1.44 M glucose solution will contain precisely 0.400 moles of dissolved glucose (give your answer in liters to three significant digits)?

6 points

QUESTION 11

1. Which of the following aqueous solutions would result in the greatest osmotic pressure if it were separated from pure water by a semi-permeable membrane? In other words, which of the following solutions exhibits the highest “osmolarity”?

   0.5 M (NH4)2SO4

   0.5 M NaCl

   0.5 M Ca(NO3)2

   0.5 M C6H12O6

   0.5 M K3PO4

6 points

QUESTION 12

1. What is the molar concentration of the solution that results after 600 milliliters of water are added to 200 milliliters of a 0.8 M solution of (NH₄)₂SO₄? Give only the molar concentration of the resultant solution without units in your answer.

5 points

QUESTION 13

1. Imagine you are working in a laboratory on a vaccine against SARS-CoV-2 and a particular procedure requires that you first prepare 200 mL of 150 mM sucrose solution. You look on the shelf above your bench and locate a stock 1 M sucrose solution. What volume of the concentrated stock 1 M sucrose do you need to dilute in water to produce your desired solution? (HINT: Give your answer in milliliters, without units, and “mM” means “millimolar”, which is “millimoles/liter”)