Answers 25-26 KCS18 Chemistry ICArrhenius, Bronsted-Lowry, and Lewis Acids and Bases

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The molar mass of KCl is 74.55 g/mol. If 8.45 g KCl are dissolved in 0.750 L of solution, what is the molarity of the solution?Use .

0.113 M

0.151 M

6.62 M

11.3 M

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A substance is dissolved in water and produces hydronium ions. This occurs when hydrogen ions move from the substance to associate with water molecules. Which term best matches the behavior of this substance?

Arrhenius base

Arrhenius acid

Bronsted-Lowry base

Bronsted-Lowry acid

What is the Arrhenius definition of a base?

A substance that increases H3O+ concentration when it is dissolved in water.

A substance that increases OH– concentration when it is dissolved in water.

A compound that donates protons.

A compound that accepts protons.

Which of these equations correctly expresses the self-ionization of water?

Upper H subscript 2 upper O superscript plus upper H subscript 3 upper O superscript plus double-headed arrow upper H subscript 2 upper O plus upper O upper H superscript minus.

Upper H subscript 2 upper O plus upper H subscript 2 upper O double-headed arrow 2 upper O upper H superscript minus.

Upper H subscript 2 upper o plus upper H subscript 2 upper O double headed arrow 2 upper H subscript 3 upper O superscript plus.

Upper H subscript 2 upper O plus upper H subscript 2 upper O double-headed arrow upper H subscript 3 upper O superscript plus, plus upper O upper H superscript minus.

The pH of lemon juice at 298 K is found to be 2.32. What is the concentration of ions in the solution? Use .

1.05 times 10 to the negative 3 moles per liter.

4.79 times 10 to the negative 3 moles per liter.

2.09 times 10 squared moles per liter.

9.55 times 10 squared moles per liter.

An acid is a substance that increases the concentration of H3O+ ions in solution. Look at the reaction below of phenol (C6H5OH) with water:Which reactant acts as an acid by contributing a H+ ion to create H3O+ in the chemical equation?

C6H5OH(aq)

H2O(l)

C6H5O–(aq)

H3O+(aq)

How does litmus paper identify a base?

A base turns red litmus blue.

A base turns blue litmus red.

A base turns orange litmus red.

A base turns yellow litmus blue.

Why is citric acid added to food?

to add color

to add tartness

to add bitterness

to add sweetness

An unknown substance turns methyl orange solution red. This shows that the substance

is a base.

is water.

is an acid.

is an alkaloid.

A solution containing 1.15 mol benzene dissolved in carbon tetrachloride has a concentration of 0.86 m. How many kilograms of carbon tetrachloride must the solution contain?Use .

0.29 kg

0.75 kg

0.99 kg

1.3 kg

Four different solutions (I, II, III, and IV) are labeled on the pH scale below.Why would solution IV be considered the most concentrated base out of the four substances?

It has the highest concentration of hydrogen ions.

It has the highest concentration of hydronium ions.

It has the highest concentration of oxide ions.

It has the highest concentration of hydroxide ions.

A 125 mL aqueous solution contains 1.86 10–5 g of potassium chloride and has a density of 1.02 g/mL. What is the concentration in ppm?Use .

1.46 10-7 ppm

1.82 10-5 ppm

0.146 ppm

18.2 ppm

Several substances are labeled on the pH scale below.Which substance has the lowest [H+] concentration but is still considered an acid?

milk

blood

gastric fluid

household lye

Saline is a solution that contains a certain amount of NaCl and is designed to have the same osmotic pressure as normal blood cells. Doctors often give saline to patients who have lost blood. Which of the following explains why glucose of the same molality cannot attain the same effect as saline?

Each formula unit of NaCl will give two particles because of ionization, but each molecule of glucose dissolves to give only one particle. Osmotic pressure for glucose will be lower than is required.

Glucose would not maintain osmotic pressure because on dissociation it forms two particles per formula unit, but NaCl would give only one particle per formula unit. Osmotic pressure is higher when the number of particles decreases.

Osmotic pressure increases with the decrease in the number of particles of solute in the solution. NaCl provides fewer particles per formula unit than glucose does.

Sodium and chloride ions can pass freely through the membranes of red blood cells, but glucose molecules cannot pass through the membranes.

Which characteristic best identifies an Arrhenius base?

It must donate electrons to form a covalent bond.

It must accept protons from an acid.

It must generate hydroxide ions in water.

It must form a conjugate acid after reacting.

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