A solution with a pH of 5.0 _____.

A. H+ ions

B. OH- ions

C. Na+ ions

D. Cl- ions

A) H+ ions (Correct Answer): Ethanoic acid (acetic acid) is acidic because it donates protons (H+) in solution, leading to the formation of hydronium ions (H3O+). This process characterizes acids.

B) OH- ions: Hydroxide ions (OH-) typically characterize bases, not acids. Ethanoic acid doesn't contain hydroxide ions.

C) Na+ ions: Sodium ions (Na+) are not responsible for the acidity of ethanoic acid. Na+ ions are typically found in salts and do not contribute to acidity.

D) Cl- ions: Chloride ions (Cl-) are not responsible for the acidity of ethanoic acid. Cl- ions are typically found in salts and do not contribute to acidity.

A. 7-8

B. 9-10

C. 10-13

D. 13-14

A) 7-8: This pH range suggests a neutral to slightly basic solution. Ammonia solution is typically more alkaline than this range.

B) 9-10: This pH range suggests a slightly basic solution. Ammonia solution is generally more alkaline than this range.

C) 10-13 (Correct Answer): Ammonia solution is typically alkaline and falls within the pH range of 10-13. Ammonia reacts with water to produce hydroxide ions (OH-), resulting in an alkaline solution.

D) 13-14: This pH range suggests a highly basic solution, which may be too high for typical ammonia solutions. Ammonia solutions are usually within the pH range of 10-13.

A. Red

B. Yellow

C. Blue

D. Black

A) Red (Correct Answer): Acids turn litmus paper red. Litmus paper is a common indicator that changes color in response to changes in acidity or alkalinity. Acids change the blue litmus paper to red.

B) Yellow: Acids do not typically turn litmus paper yellow. Litmus paper is generally unaffected by acids in a way that would cause it to turn yellow.

C) Blue: Acids do not turn litmus paper blue. Instead, they change blue litmus paper to red.

D) Black: Acids do not turn litmus paper black. Litmus paper is not expected to change to black in the presence of acids.

A. Yellow, green, and blue colors.

B. Green, blue, and purple colors.

C. White, grey, and black colors.

D. Yellow, orange, and red colors

A. Yellow, green, and blue colors: This sequence of colors does not represent the typical color changes observed in universal indicator when exposed to acidic solutions. Universal indicator typically changes from green/blue in neutral solutions to yellow/orange/red in acidic solutions.

B. Green, blue, and purple colors: Purple is not typically observed in the color changes of universal indicator in acidic solutions. Universal indicator usually transitions from green/blue in neutral solutions to yellow/orange/red in acidic solutions.

C. White, grey, and black colors: These colors are not typically observed in the color changes of universal indicator. Universal indicator undergoes a series of color changes from green/blue to yellow/orange/red in acidic solutions.

D. Yellow, orange, and red colors. (Correct Answer): Universal indicator typically changes from green/blue in neutral solutions to yellow/orange/red in acidic solutions. This sequence of colors represents the typical color changes observed in universal indicator when exposed to acidic solutions.

A. pH 2-4

B. pH 1-3

C. pH 0-2

D. pH 3-5

Rationale for each choice:

A) pH 2-4: While hydrochloric acid is indeed highly acidic, a pH range of 2-4 would suggest a slightly less concentrated solution. However, this range might still be appropriate for dilute or partially neutralized hydrochloric acid.

A) pH 1-3 (Correct Answer): Hydrochloric acid typically has a very low pH due to its strong acidic nature. A pH range of 1-3 is commonly observed for concentrated hydrochloric acid solutions.

C) pH 0-2: This range suggests an even stronger acidity, which could be true for very concentrated hydrochloric acid solutions, although they might not commonly occur in typical laboratory or industrial settings.

D) pH 3-5: This pH range would indicate a significantly less acidic solution compared to hydrochloric acid. Such a pH range might be more appropriate for weak acids or diluted hydrochloric acid solutions rather than the concentrated form.

A. To provide energy for photosynthesis

B. To build cellulose in cell walls

C. To build amino acids and proteins

D. To regulate water uptake

A) To provide energy for photosynthesis: While nitrogen is essential for various metabolic processes in plants, it is not directly involved in providing energy for photosynthesis. Instead, plants use sunlight to convert carbon dioxide and water into glucose during photosynthesis.

B) To build cellulose in cell walls: Nitrogen is not directly involved in the synthesis of cellulose, which is primarily composed of glucose units. Cellulose synthesis mainly relies on carbon and hydrogen, which are obtained from carbon dioxide and water during photosynthesis.

C) To build amino acids and proteins: Plants use nitrogen from fertilizers to synthesize amino acids and proteins. Nitrogen is a crucial component of amino acids, the building blocks of proteins, which are essential for plant growth, development, and various physiological processes.

D) To regulate water uptake (Correct Answer): Nitrogen plays a role in regulating various physiological processes in plants, including water uptake. It affects the osmotic potential of plant cells and helps regulate the movement of water and nutrients within the plant.

A. has a hydrogen-ion concentration of 5.0M

B. is neutral

C. has a hydroxide-ion concentration of 1 x 10 –9 M

D. None of the above

a. is basic: Incorrect. Solutions with pH values less than 7 are acidic, not basic. A pH of 5.0 indicates an acidic solution.

b. has a hydrogen-ion concentration of 5.0M: Incorrect. The pH value does not directly provide information about the concentration of hydrogen ions. pH is a logarithmic scale that measures the concentration of hydrogen ions in a solution.

c. is neutral: Incorrect. Solutions with a pH of 7 are considered neutral. A pH of 5.0 indicates an acidic solution.

d. has a hydroxide-ion concentration of 1 x 10 –9 M: Incorrect. This statement relates to the calculation of hydroxide-ion concentration in a neutral solution using the Kw value (the ion product of water). It does not directly pertain to the pH value of the solution.

A. Salt and water

B. Carbon dioxide and water

C. Oxygen gas and water

D. Salt and hydrogen

A) Salt and water: This reaction occurs when an acid reacts with a metal hydroxide or a metal oxide. When metals react with acids, hydrogen gas is typically produced along with a salt, not water.

B) Carbon dioxide and water: This reaction occurs when an acid reacts with a metal carbonate, not a metal. When carbonates react with acids, carbon dioxide gas is produced along with water and a salt.

C) Oxygen gas and water: This reaction is not typical when an acid reacts with a metal. Metal reactions with acids usually produce hydrogen gas along with a salt.

D) Salt and hydrogen (Correct Answer): When an acid reacts with a metal, hydrogen gas is produced along with a salt. The metal displaces hydrogen ions from the acid, forming a salt, while hydrogen gas is released as a byproduct of the reaction.

A. Filtration

B. Distillation

C. Decantation

D. Evaporation

A) Filtration: Filtration is not suitable for separating dissolved substances from a solution. It is typically used to separate solid particles from a liquid mixture.

B) Distillation: Distillation is a process used to separate components of a mixture based on differences in their boiling points. It is not typically used to separate solid crystals from a solution.

C) Decantation: Decantation involves pouring off the liquid portion of a mixture, leaving the solid behind. While it can be used to separate solid and liquid phases, it may not effectively separate dissolved copper sulfate from the solution.

D) Evaporation (Correct Answer): Evaporation involves heating the solution to allow the solvent (water) to vaporize, leaving behind the solute (copper sulfate) as solid crystals. This process is commonly used to obtain solid crystals from a solution.

A. NH4SO4

B. (NH4)2SO4

C. (NH4)SO4

D. (NH3)2SO4

A) NH4SO4: This formula suggests a compound where one ammonium ion is combined with one sulfate ion, which is not the correct composition of ammonium sulfate.

B) (NH4)2SO4 (Correct Answer): This formula correctly represents ammonium sulfate, indicating that it consists of two ammonium ions (NH4+) and one sulfate ion (SO4^2-).

C) (NH4)SO4: This formula suggests a compound with one ammonium ion combined with one sulfate ion, which is not the correct composition of ammonium sulfate.

D) (NH3)2SO4: This formula suggests a compound where two ammonia molecules (NH3) are combined with one sulfate ion, which is incorrect. Ammonium sulfate contains ammonium ions (NH4+), not ammonia molecules (NH3).