Chapter 9 HW

What is the overall balanced equation for the precipitation reaction occurring between silver nitrate and calcium bromide?

2AgNO3(aq)+CaBr2(aq)→2AgBr(s)+Ca(NO3)2(aq)

Watch the animation and select the interactions that can be explained by hydrogen bonding. Check all that apply.

*HF has a higher boiling point than HCl. *Ice, H2O, has a solid structure with alternating H−O interactions.

Suppose that NaCl is added to hexane instead of water. Which of the following intermolecular forces will exist in the system? Check all that apply.

*Ion-ion force between Na+ and Cl− ions *London dispersion force between two hexane molecules

What is the solubility of CO2 in a soft drink (which is mainly water) that was bottled under a CO2 pressure of 4.6 atm? Express your answer using two significant figures.

0.69 g/(100 mL)

How many liters of a 3.49 M K2SO4 solution are needed to provide 73.9 g of K2SO4(molar mass 174.01 g/mol)? Recall that M is equivalent to mol/L. Express your answer to three significant figures.

ANSWER: 0.122 L (Formula: 7.39 x (1 mole / 174.01 g) x (1 L / 3.49 mol) = 0.122 L )

In order to understand how this equation is derived and why it holds true, the product of each side of the equation should be examined. What value and unit do you get when you multiply a concentration of 0.796 M by a volume of 0.550 L? This question can be expressed as 0.550 L / 1 ×0.796 mol / L= Express your answer to three significant figures with the appropriate units.

ANSWER: 0.438 mol (.550 X .0796= 0.438 mol)

Calculate the molarity (M) of 153.2 g of H2SO4 in 1.430 L of solution. Express your answer to four significant figures.

ANSWER: 1.092 M (FORMULA: 153.2 / (98.082 X 1.4300 = 1.092 M)

The absorbance of a cationic iron(II) sample solution was measured in a spectrophotometer, but the instrument returned an error because the absorbance was too high. The sample was then diluted by using a pipette to take 100.0 μL of the sample and injecting it into a cuvette already containing 2.00 mL of water (total volume is 2.00 mL + 100.0 μL). The absorbance value of the diluted solution corresponded to a concentration of 7.11×10−6 M . What was the concentration of the original solution? Express the concentration to three significant figures with the appropriate units.

ANSWER: 1.49*10^-4 m (FORMULA: (7.11 x 10^-6 x 2100) / 100= 1.49 x10^-4 M)

Vinegar is a solution of acetic acid in water. If a 185 mL bottle of distilled vinegar contains 21.7 mL of acetic acid, what is the volume percent (v/v) of the solution? Express your answer to three significant figures.

ANSWER: 11.7% (NOTE: volume of solute: 21.7 ML volume of solution: 325 mL (21.7 mL) / (185 mL) x 100 = 11.7%

Calculate the mass percent of a solution that is prepared by adding 73.7 g of NaOH to 246 g of H2O. Express your answer numerically.

ANSWER: 17.0 % (FORMULA: -mass of solute: 182 g -mass of solvent: 1.07 L (1070 mL) (182 g / 1070 mL) x 100 = 17.0 % NOTE: The mass/volume percent (sometimes called weight/volume percent) is the method commonly used in hospitals in the preparation of IV (intravenous) solutions.)

Part A Calculate the mass percent (m/m) of a solution prepared by dissolving 40.47 g of NaCl in 175.0 g of H2O. Express your answer to four significant figures.

ANSWER: 18.78 % (mass of NaCl: 40.47 g Mass of H2O: 175.50 H20 Mass of solution: 40.47 g + 175.0 g= 215.47 g %mm= (40.47 g) / (215.47 g) x 100 = 18.78 % The mass percent (m/m) of the solution is 18.78 %)

Calculate the mass/volume percent (m/v) of 22.0 g NaCl in 71.0 mL of solution. Express your answer to three significant figures.

ANSWER: 31.0% (NOTE: (22.0 ) / (71.0) x 100= 31.0% The mass/volume percent (m/v) is 31.0 %)

When you need to produce a variety of diluted solutions of a solute, you can dilute a series of stock solutions. A stock solution has a significantly higher concentration of the given solute (typically 101 to 104 times higher than those of the diluted solutions). The high concentration allows many diluted solutions to be prepared using minimal amounts of the stock solution. What volume of a 6.51 M stock solution do you need to prepare 100. mL of a 0.2799 M solution of HCl? Express the volume to three significant figures with the appropriate units.

ANSWER: 4.30 mL (formula: M1: 6.51 M V1: ? M2: 0.2799 M V2: 100 mL V1= (0.2799 M x 100 mL) / 6.51 M = 4.2995 ==> 4.30 mL

A solution of rubbing alcohol is 78.1 % (v/v) isopropanol in water. How many milliliters of isopropanol are in a 88.8 mL sample of the rubbing alcohol solution? Express your answer to three significant figures.

ANSWER: 69.35 mL (formula: (78.1 x 88.8) / 100 = 69.35 mL)

An atmospheric concentration of 380 ppm CO2 corresponds to a partial pressure of 0.00038 atm. What percentage of the CO2 originally dissolved in the solution in Part A remains in solution after the soft drink reaches equilibrium with the ambient atmosphere? Express your answer using two significant figures.

ANSWER: 8.3*10^-3 (% of CO2 = 0.00038atm / 4.6atm x 100 = 8.3 x 10^-3 %0

One bottle of soda is stored in a refrigerator at 3 ∘C, and another is stored at room temperature (25 ∘C). If both bottles were opened simultaneously, which one would exhibit greater carbonation (i.e., have more bubbles) and why?

ANSWER: The solubility of CO2 decreases with increasing temperature, so the warmer bottle will lose its carbonation faster. (NOTE: Increasing the temperature decreases the solubility of a gas in a liquid and decreasing the temperature increases the solubility of a gas. When soda is warmed by increasing the temperature, CO2 gas is released from the soda in the form of bubbles, which makes the carbonation faster. This results in a decrease in the amount of dissolved CO2 gas in the solvent. However, when soda is cold, more CO2 gas remains in the solvent upon opening the bottle.)

Using the introduction's definition for each type of concentration, determine the Conversion Factor Required that, when multiplied by the Given Unit, will provide the correct Desired Unit answer. Drag the appropriate labels to their respective targets.

ANSWERS from top to bottom: 30 g NaCl/ 100 g solution 8mL ethanol/ 100 mL solution 14 g fructose/ 100 mL solution 1 L solution / 5.0 mol HBr

Water and toluene are not miscible. Which of the following is most likely the formula of toluene?

C6H5CH3

Which of the following will be the most soluble in water?

CH3CH2CH2OH

What precipitate will form when aqueous solutions of sodium carbonate (Na2CO3) and calcium chloride (CaCl2) are mixed?

CaCO3(s) (NOTE: Na2CO3(aq) + CaCl2(aq) -------> CaCO3(s) + 2NaCl(aq))

Watch the animation in the activity, and rank the events in the order that they occur as equilibrium is reached, keeping in mind that some events may occur simultaneously. Rank from first step to last step. To rank items as equivalent, overlap them.

FIRST STEP: hydration of cations hydration of anions dissociation of salt into its cations and anions SECOND STEP: dissolved cations and anions begin to deposit as a solid salt LAST STEP (3RD STEP) rate of dissolution is equal to the rate of recrystallization (overlap the first 3 on first step.)

Identify which of the following molecules can exhibit hydrogen bonding as a pure liquid. Check all that apply.

H-O-O-H H-O-H H-N-N-H w/ two H above the two N's.

The hydrides of group 5A are NH3, PH3, AsH3, and SbH3. Arrange them from highest to lowest boiling point. Rank the molecules from highest to lowest boiling point. To rank items as equivalent, overlap them.

Highest to Lowest (left to right) SbH3 NH3 AsH3 PH3

Classify the substances according to the strongest solute-solvent interaction that will occur between the given substances and water during dissolution. Drag the appropriate items to their respective bins.

Ion-dipole Forces: CuCl2 CuSo4 Hydrogen bonding: CH3OH HF

Consider the following ionic compounds: CdCO3, Na2S, PbSO4, (NH4)3PO4, and Hg2Cl2. Which compounds will be soluble when added to water?

Na2S and (NH4)3PO4

Predict the products for the following precipitation reaction: NiCl2(aq)+(NH4)2S(aq)→

NiS(s) + 2NH4Cl(aq) (full formula: NiCl2(aq)+(NH4)2S(aq)→ NiS(s) + 2NH4Cl(aq)

Identify the type of interactions involved in each of the following processes taking place during the dissolution of sodium chloride (NaCl) in water. Drag the appropriate items to their respective bins.

Solvent-solvent interactions: *interactions involving dipole-dipole attractions *interactions between the water molecules Solute-solute interactions: *interactions involving ion-ion attraction *interactions between the ions of sodium chloride Solute-solvent interactions: * interactions formed between the sodium ions and the oxygen atoms of water molecules * interactions formed during hydration

Five different substances are given to you to be dissolved in water. Which substances are most likely to undergo dissolution in water? Check all that apply.

ethanol, CH3CH2OH sodium fluoride, NaF potassium bromide, KBr

NaCl is an ionic solid. The Na+ and Cl− ions in NaCl are bonded through an electrostatic force of attraction commonly known as the ionic bond. Water is a polar solvent. The oxygen atom, being more electronegative, attracts the electron cloud toward itself. As the electron cloud is pulled by the oxygen atom, it carries a partial negative charge, and the hydrogen atoms carry a partial positive charge. This partial separation of charges in the water molecule makes it polar. Which intermolecular forces contribute to the dissolution of NaCl in water? Check all that apply.

ion-dipole forces