2.2 Vocabulary

weak attraction between slightly positive hydrogen atom and another atom that is slightly negatiave

• hydrogen bond

• covalent bond

• ionic bond

Answer explanation

The weak attraction described is a hydrogen bond, which occurs between a slightly positive hydrogen atom and a slightly negative atom, typically oxygen or nitrogen. This distinguishes it from covalent and ionic bonds.

attraction between molecules of the same substance

• hydrogen bond

• cohesion

• adhesion

• Van der Waals forces

Answer explanation

Cohesion refers to the attraction between molecules of the same substance, such as water molecules sticking together. This is different from adhesion, which is the attraction between different substances.

force of attraction between different types of molecules

• hydrogen bond

• cohesion

• adhesion

• Van der Waals forces

Answer explanation

Adhesion refers to the force of attraction between different types of molecules, such as water molecules sticking to a glass surface. This distinguishes it from cohesion, which is the attraction between similar molecules.

a compound that prevents sharp, sudden changes in pH is a(n)

• acid

• base

• buffer

Answer explanation

A buffer is a compound that helps maintain a stable pH by neutralizing small amounts of acids or bases, preventing sharp changes in pH levels. Therefore, the correct answer is buffer.

The curvature of the water in a test tube - referred to as the meniscus is due to

• cohesion

• adhesion

• both cohesion and adhesion

Answer explanation

The curvature of the water in a test tube, known as the meniscus, is primarily due to adhesion. Water molecules are attracted to the glass, causing the liquid to climb up the sides, while cohesion keeps the water molecules together.

a bug's ability to walk on water is due to

• cohesion

• adhesion

• cohesion and adhesion

Answer explanation

A bug's ability to walk on water is primarily due to cohesion, which is the attraction between water molecules that creates surface tension. This allows the bug to stay on the surface without sinking.

Capillary action- the movement upward in a small tube is due to

• cohesion

• adhesion

• cohesion and adhesion

Answer explanation

Capillary action occurs due to both cohesion and adhesion. Cohesion is the attraction between like molecules, while adhesion is the attraction between unlike molecules. Together, they enable liquid to rise in a small tube.

type of mixture in which all the components are evenly distributed

• compound

• solution

• solute

• suspension

Answer explanation

A solution is a type of mixture where all components are evenly distributed at the molecular level, unlike suspensions where particles are not uniformly distributed. Therefore, the correct answer is 'solution'.

material composed of two or more elements or compounds that are physically mixed together but not chemically combined

• mixture

• compound

• solution

• suspension

• solute

Answer explanation

A mixture is defined as a material composed of two or more elements or compounds that are physically mixed together but not chemically combined. This distinguishes it from compounds, which are chemically bonded.

a substance with a pH less than 7 is a(n)

• acid

• base

• buffer

Answer explanation

A substance with a pH less than 7 is classified as an acid. Acids release hydrogen ions in solution, which lowers the pH, while bases have a pH greater than 7 and increase hydroxide ions.