Question 1

A 38.1-g sample of SrCl₂ is dissolved in 112.5 mL of solution.Calculate the molarity of this solution.

Accepted Answer

To find the molarity, divide the moles of solute by the liters of solution. The molar mass of SrCl₂ is approximately 158.53 g/mol. Thus, 38.1 g SrCl₂ is 0.240 moles. The volume of the solution is 0.1125 L. Molarity = 0.240 moles / 0.1125 L = 2.14 M.

Question 2

Which of the following aqueous solutions contains the greatest number of ions?

Accepted Answer

CaCl2 ionizes into three ions (one calcium ion and two chloride ions) in aqueous solution. 
NaCl, FeCl3, and KBr ionize into two ions each (one cation and one anion).
Sucrose does not ionize and therefore does not contribute any ions. 
So, the solution with the greatest number of ions is the one with the salt that ionizes into the most ions, which is CaCl2.

Question 3

Polar molecules have an unequal distribution of charge within the molecule.

Accepted Answer

Polar molecules have an unequal distribution of charge within the molecule, meaning that one part of the molecule has a slightly positive charge and another part has a slightly negative charge, resulting in partial positive and negative charges within the molecule.

Question 4

How many grams of NaCl are contained in 350.mL of a 0.287 M solution of sodium chloride?

Accepted Answer

To find the grams of NaCl, use the formula: grams = molarity (M) × volume (L) × molar mass (g/mol). The molar mass of NaCl is approximately 58.44 g/mol. Convert 350 mL to liters (0.350 L) and calculate: 0.287 M × 0.350 L × 58.44 g/mol = 5.87 g.

Question 5

All of the following are weak acids except

Accepted Answer

HBr is a strong acid, while the other options listed are weak acids.

Question 6

Consider two organic molecules,ethanol and benzene.One dissolves in water and the other does not.Why?

Accepted Answer

Ethanol contains a polar O-H bond, which allows it to form hydrogen bonds with water molecules and dissolve in water. Benzene, on the other hand, is a nonpolar molecule and cannot form hydrogen bonds with water molecules, so it does not dissolve in water. Factors like molar mass, ionic nature, and electrolytic properties are not relevant in this case.

Question 7

The man who discovered the essential nature of acids through solution conductivity studies is

Accepted Answer

The man who discovered the essential nature of acids through solution conductivity studies is Svante Arrhenius.

Question 8

A solid acid HX is mixed with water.Two possible solutions can be obtained.Which of the following is true? I.  II.

Accepted Answer

In case I, HX is acting like a weak acid because it only partially dissociates in water, resulting in a solution with a lower concentration of H+ ions. In case II, HX is acting like a strong acid because it completely dissociates in water, resulting in a solution with a higher concentration of H+ ions. Therefore, the answer is B.

Question 9

What mass of calcium chloride,CaCl₂,is needed to prepare 3.950 L of a 1.49 M solution?

Accepted Answer

The answer of What mass of calcium chloride,CaCl₂,is needed to...

Question 10

A 74.28-g sample of Ba(OH)₂ is dissolved in enough water to make 2.450 liters of solution.How many mL of this solution must be diluted with water in order to make 1.000 L of 0.100 M Ba(OH)₂?

Accepted Answer

First, determine the molarity of the original solution. The molar mass of Ba(OH)2 is approximately 171.34 g/mol (137.33 for Ba + 2*(16 for O + 1 for H)). Thus, 74.28 g of Ba(OH)2 is 74.28 g / 171.34 g/mol = 0.433 mol. The molarity of the original solution is 0.433 mol / 2.450 L = 0.177 M. Using the dilution formula M1V1 = M2V2, where M1 is the initial molarity (0.177 M), V1 is the volume of the solution needed, M2 is the final molarity (0.100 M), and V2 is the final volume (1.000 L), we can solve for V1: V1 = (M2V2) / M1 = (0.100 M * 1.000 L) / 0.177 M = 0.565 L, which is 565 mL.

Question 11

An unknown substance dissolves readily in water but not in benzene (a nonpolar solvent).Molecules of what type are present in the substance?

Accepted Answer

The fact that the substance dissolves readily in water, which is a polar solvent, suggests that the substance must be polar. Nonpolar substances do not dissolve in polar solvents like water, and benzene is a nonpolar solvent. Therefore, the substance must be polar in order to dissolve in water and not in benzene.

Question 12

An acid is a substance that produces OH^- ions in water.

Accepted Answer

An acid is a substance that produces H+ ions in water, not OH^- ions.

Question 13

How many grams of NaOH are contained in 5.0 $\times$ 10² mL of a 0.74 M sodium hydroxide solution?

Accepted Answer

The correct answer is A because the number of moles of NaOH in 5.0 x 10^2 mL of a 0.74 M solution is:Moles of NaOH = Molarity x Volume (in liters)Moles of NaOH = 0.74 M x 0.500 LMoles of NaOH = 0.37 molesThe mass of NaOH in grams is:Mass of NaOH = Moles of NaOH x Molar mass of NaOHMass of NaOH = 0.37 moles x 40.00 g/molMass of NaOH = 15 g

Question 14

Which of the following is a strong acid?

Accepted Answer

HClO₄ (perchloric acid) is a strong acid, meaning it completely dissociates in water.

Question 15

A 16.4-g sample of HF is dissolved in water to give 2.0 $\times$ 10² mL of solution.The concentration of the solution is:

Accepted Answer

First, we need to calculate the number of moles of HF in the solution:
n(HF) = m(HF) / MM(HF) = 16.4 g / 20.01 g/mol = 0.819 moles HF

Next, we need to calculate the volume of the solution in liters:
V = 2.0 x 10^-10 m^3 x (1 L / 1000 cm^3) = 2.0 x 10^-13 L

Finally, we can calculate the concentration of the solution:
C = n(HF) / V = 0.819 moles / 2.0 x 10^-13 L = 4.1 M

Therefore, the correct answer is D.

Question 16

What mass of solute is contained in 256 mL of a 0.838 M ammonium chloride solution?

Accepted Answer

The correct answer is A because the mass of solute can be calculated using the formula: mass of solute = concentration × volume of solution × molar mass of solute. The molar mass of ammonium chloride is 53.49 g/mol. So, the mass of solute in 256 mL of a 0.838 M ammonium chloride solution is: mass of solute = 0.838 M × 0.256 L × 53.49 g/mol = 11.5 g.

Question 17

Which of the following is not a strong base?

Accepted Answer

Among the given choices, the weak base is NH3 (ammonia). NH₃ is not a strong base as NH3 is a weak base and it only has one associated OH group. The rest of the choices are all strong bases as they have multiple hydroxide ions (OH-) associated with them.

Question 18

Which of the following is paired incorrectly?

Accepted Answer

HNO₃ is not a known chemical formula. It is possible that the correct formula was intended to be HNO3, which is a strong acid.

Question 19

What volume of 18 M sulfuric acid must be used to prepare 2.30 L of 0.145 M H₂SO₄?

Accepted Answer

To prepare a solution with a lower concentration from a solution with a higher concentration, we use the dilution equation:M1V1 = M2V2where M1 and V1 are the initial concentration and volume, and M2 and V2 are the final concentration and volume.We are given:M1 = 18 MV2 = 2.30 LM2 = 0.145 MSolving for V1:V1 = (M2V2) / M1V1 = (0.145 M * 2.30 L) / 18 MV1 = 0.019 L = 19 mLTherefore, the correct answer is A) 19 mL.

Question 20

The interaction between solute particles and water molecules,which tends to cause a salt to fall apart in water,is called

Accepted Answer

When a salt is dissolved in water, the water molecules surround the ions in the salt and form hydration shells around them. This process is known as hydration and is the reason why salts tend to fall apart in water. The other options (polarization, dispersion, coagulation, and conductivity) do not accurately describe the interaction between solute particles and water molecules that causes salts to dissolve in water.

Quiz 4: Chemical Reactions and Solutions Stoichiometry

A 38.1-g sample of SrCl₂ is dissolved in 112.5 mL of solution.Calculate the molarity of this solution.

Which of the following aqueous solutions contains the greatest number of ions?

Polar molecules have an unequal distribution of charge within the molecule.

How many grams of NaCl are contained in 350.mL of a 0.287 M solution of sodium chloride?

All of the following are weak acids except

Consider two organic molecules,ethanol and benzene.One dissolves in water and the other does not.Why?

The man who discovered the essential nature of acids through solution conductivity studies is

A solid acid HX is mixed with water.Two possible solutions can be obtained.Which of the following is true? I. II.

What mass of calcium chloride,CaCl₂,is needed to prepare 3.950 L of a 1.49 M solution?

A 74.28-g sample of Ba(OH) ₂ is dissolved in enough water to make 2.450 liters of solution.How many mL of this solution must be diluted with water in order to make 1.000 L of 0.100 M Ba(OH) ₂?

An unknown substance dissolves readily in water but not in benzene (a nonpolar solvent) .Molecules of what type are present in the substance?

An acid is a substance that produces OH^- ions in water.

How many grams of NaOH are contained in 5.0 $\times$ 10² mL of a 0.74 M sodium hydroxide solution?

Which of the following is a strong acid?

A 16.4-g sample of HF is dissolved in water to give 2.0 $\times$ 10² mL of solution.The concentration of the solution is:

What mass of solute is contained in 256 mL of a 0.838 M ammonium chloride solution?

Which of the following is not a strong base?

Which of the following is paired incorrectly?

What volume of 18 M sulfuric acid must be used to prepare 2.30 L of 0.145 M H₂SO₄?

The interaction between solute particles and water molecules,which tends to cause a salt to fall apart in water,is called

Quiz 4: Chemical Reactions and Solutions Stoichiometry

A 38.1-g sample of SrCl2 is dissolved in 112.5 mL of solution.Calculate the molarity of this solution.

Which of the following aqueous solutions contains the greatest number of ions?

Polar molecules have an unequal distribution of charge within the molecule.

How many grams of NaCl are contained in 350.mL of a 0.287 M solution of sodium chloride?

All of the following are weak acids except

Consider two organic molecules,ethanol and benzene.One dissolves in water and the other does not.Why?

The man who discovered the essential nature of acids through solution conductivity studies is

A solid acid HX is mixed with water.Two possible solutions can be obtained.Which of the following is true? I. II.

What mass of calcium chloride,CaCl2,is needed to prepare 3.950 L of a 1.49 M solution?

A 74.28-g sample of Ba(OH) 2 is dissolved in enough water to make 2.450 liters of solution.How many mL of this solution must be diluted with water in order to make 1.000 L of 0.100 M Ba(OH) 2?

An unknown substance dissolves readily in water but not in benzene (a nonpolar solvent) .Molecules of what type are present in the substance?

An acid is a substance that produces OH- ions in water.

How many grams of NaOH are contained in 5.0 ×\times× 102 mL of a 0.74 M sodium hydroxide solution?

Which of the following is a strong acid?

A 16.4-g sample of HF is dissolved in water to give 2.0 ×\times× 102 mL of solution.The concentration of the solution is:

What mass of solute is contained in 256 mL of a 0.838 M ammonium chloride solution?

Which of the following is not a strong base?

Which of the following is paired incorrectly?

What volume of 18 M sulfuric acid must be used to prepare 2.30 L of 0.145 M H2SO4?

The interaction between solute particles and water molecules,which tends to cause a salt to fall apart in water,is called

A 38.1-g sample of SrCl₂ is dissolved in 112.5 mL of solution.Calculate the molarity of this solution.

What mass of calcium chloride,CaCl₂,is needed to prepare 3.950 L of a 1.49 M solution?

A 74.28-g sample of Ba(OH) ₂ is dissolved in enough water to make 2.450 liters of solution.How many mL of this solution must be diluted with water in order to make 1.000 L of 0.100 M Ba(OH) ₂?

An acid is a substance that produces OH^- ions in water.

How many grams of NaOH are contained in 5.0 $\times$ 10² mL of a 0.74 M sodium hydroxide solution?

A 16.4-g sample of HF is dissolved in water to give 2.0 $\times$ 10² mL of solution.The concentration of the solution is:

What volume of 18 M sulfuric acid must be used to prepare 2.30 L of 0.145 M H₂SO₄?