Modules 7-9

Which of the solutions below represents the STRONGEST acid?

(C)

Calculate the energy change for the reaction of 2 moles of HI to produce 1 mol of H2 and 1 mol of I2, given the average bond energies.2HI → H2 + I2H-H (bond energy: 436 kJ/mol)I-I (bond energy: 151 kJ/mol)H-I (bond energy: 297 kJ/mol)

+ 7 kJ

Which of the following are correct statements about solutions? Select all that apply, this is a multiple response question.

-Solutions are homogeneous mixtures. -The solvent in a solution is the substance present in the greatest amount.

Which of the following solutions would be considered acidic? Select all that apply, this is a multiple response question.

-a solution with pH = 3 -a solution with [H3O+] = 1.0 x 10-5

Sodium hydroxide (a strong base) is added to a buffer solution of acetic acid (a weak acid) and acetate (a weak base). What is the effect on the concentration of acetic acid? What is the effect on the concentration of acetate?

-the concentration of acetic acid: decreases -the concentration of acetate: increases

How many liters (L) of a 2.50 M solution would contain 0.450 moles of solute?

0.180 L

Which sample would have the greatest mass in grams?

1 mol Si

What is the molar mass of Fe(OH)3? (A mol of Fe(OH)3 would have a mass of how many grams?)

106.9 g/mol

What is the mass of zinc sulfide (ZnS) required to produce 12.8 grams of zinc phosphide (Zn3P2) according to the following balanced equation?3ZnS + 2AlP → Zn3P2 + Al2S3

14.5 grams

Choose the correct coefficient for each reactant and product to correctly balance the chemical equation below, the decomposition of potassium chlorate to form potassium chloride and oxygen:___ KClO3 → ___KCl + ___ O2

2 2 3

Arrange the following types of intermolecular attractive forces from strongest to weakest. (1 = strongest, 4 = weakest) Dipole-Dipole Induced dipole-induced dipole Ion-dipole Dipole- induced dipole

2 4 1 3

Which sample would have the greatest number of atoms?

2 mol Na

Which of the following solutions in the MOST CONCENTRATED?

30 grams of solute in 50 grams of solution

What is the pH of a solution that has a hydronium ion (H3O+) concentration of 2.8 x 10-5 M?

4.55

How many moles of water (H2O) would be required to react with 2.50 moles of calcium according to the balanced equation below:Ca + 2H2O → Ca(OH)2 + H2

5.00 moles

How many molecules of glucose are in 0.40 L of a 3.0 M solution of glucose?

7.22 x 1023 molecules

identify each of the solutions below as acidic, basic or neutral.

Basic Neutral Acidic

Which of the following molecules would NOT be capable of hydrogen bonding? Select all that apply, this is a multiple response question.

CH4 N2 CO2

Water is considered "hard" when it contains high amounts of which TWO ions (i.e. select two answers):

Ca2+ Mg2+

For the acid-base reaction below, identify the other product formed.HF + Ca(OH)2 → H2O + ?????

CaF2

In the chemical equation below, which substances would be considered reactants? Select all that apply this is a multiple response question.HCl + NaOH → H2O + NaCl

HCl NaOH

How readily an acid donates a hydrogen ion is a function of how well the acid is able to accommodate the resulting negative charge it gains after donating. Which should be the stronger acid, HClO4 or HClO2? Why?

HClO4, because the resulting negative charge is spread over a greater number of highly electronegative oxygen atoms.

Which compound in the acid-base reaction below is acting as an acid?KOH + HNO3 → H2O + KNO3

HNO3

What is an exothermic reaction?

It is a reaction that generates heat as a product.

Why do red blood cells, which contain an aqueous solution of dissolved ions and minerals, burst when placed in fresh water?

More water molecules enter the cell (through osmosis) than leave the cell.

In the destruction of ozone molecules by chlorinated fluorocarbons, the chlorinated fluorocarbons are acting as a(n) ________, by converting hundreds of thousands of ozone molecules (O3) to O2 without being used up.

catalyst

If the pH of a solution increases from 3 to 5, how did the hydronium ion (H3O+) concentration change?

The hydronium ion concentration decreased by a factor of 100.

How does a soap molecule dissolved in water orient itself around a particle of oil?

The nonpolar tail points towards the oil and the polar head points towards the water.

How would an increase in global temperature affect the solubility of carbon dioxide dissolved in ocean water?

The solubility of carbon dioxide would decrease.

The solubility of a given substance in water is 36.0 grams per liter. If 18.0 grams of the substance are dissolved in 0.500 L of water, which of the statements below would best describe the solution?

The solution is saturated.

Ion-Dipole

attractive force between an ion and the oppositely charged end of a polar molecule.

Dipole-Dipole

attractive force between two oppositely charged polar molecules

Of the following boxes containing reactants in a chemical reaction, which of the reactions below would you predict to proceed the slowest?

c

Carbon dioxide reacts with water to form

carbonic acid (H2CO3)

endothermic

energy absorbed during the chemical reaction

exothermic

energy released during the chemical reaction

Which of the following atoms would be the most polarizable?

germanium (Ge)

Dipole-Induced Dipole

polar molecule and nonpolar molecule

As hard water passes through a water softening unit

the Ca2+ and Mg2+ ions in the hard water are replaced with Na+ ions

• solvent

what does the dissolving (present in largest amount)

solute

what gets dissolved (present in smallest amount)

soap: contains both polar and nonpolar ends

• nonpolar end interacts with dirt, oil, etc. • polar end interacts with water

Induced dipole-Induced dipole

• results from randomness of electron distribution at any given point in time (temporary dipole)