Compound Chemistry Quiz (Chapter 4)

During a chemical reaction, reactants undergo a transformation and combine to form new substances. These newly formed substances are referred to as products. The products are the result of the chemical reaction and are different from the reactants. They have their own set of properties and characteristics that are distinct from the initial reactants. Therefore, the correct answer is "products."

An acid is a substance that tastes sour, conducts electricity, and donates hydrogen ions. Acids have a pH value less than 7 and can react with bases to form salts and water. They are commonly found in fruits such as lemons and vinegar. When dissolved in water, acids release hydrogen ions (H+) which make them conduct electricity. The sour taste of acids is due to the presence of these hydrogen ions.

pH means potential for hydrogen. This is because pH is a measure of the concentration of hydrogen ions in a solution. It indicates the acidity or alkalinity of a substance, with a lower pH indicating higher acidity and a higher pH indicating higher alkalinity. The term "potential" refers to the ability of hydrogen ions to react with other substances, determining their chemical properties. Therefore, pH is a measure of the potential of a substance to release or accept hydrogen ions in a chemical reaction.

An exothermic reaction occurs when energy is released during a chemical reaction. This means that the products of the reaction have less energy than the reactants, resulting in a release of heat or light. Exothermic reactions are often characterized by an increase in temperature, and examples include combustion reactions and many types of oxidation reactions.

A crystal is not formed when a gas becomes a liquid. Crystals are formed when a liquid or a gas solidifies, meaning it changes from a liquid or gas state to a solid state. So, the correct answer is false.

Diet Coke has a pH of 3, which indicates that it is acidic. Acids have a low pH value, typically below 7, and can release hydrogen ions when dissolved in water. This acidity in Diet Coke is primarily due to the presence of carbonic acid, which forms when carbon dioxide gas dissolves in water. Therefore, based on its pH value, Diet Coke is considered an acid.

The term "crystal" is not one of the four C's used to determine diamond quality. The four C's are carat (which refers to the weight of the diamond), cut (which refers to the quality of the diamond's cut and its ability to reflect light), color (which refers to the presence of any color in the diamond), and clarity (which refers to the presence of any internal or external flaws in the diamond). "Crystal" is not a factor that is considered when evaluating diamond quality.

Polymers, such as plastics, have a long decomposition time, which means they do not break down easily in the environment. This can result in a buildup of waste and contribute to the problem of excess garbage. Therefore, the statement that polymers do not decompose easily and can lead to an excess of garbage is true.

Tasting a substance is not the best way to determine whether it is an acid or base. This is because some acids and bases can be harmful or toxic to ingest. Instead, the pH scale is commonly used to determine the acidity or basicity of a substance. Acids have a pH value less than 7, while bases have a pH value greater than 7.

Borax crystals are not considered a gemstone because they do not possess the necessary characteristics to be classified as one. Gemstones are typically valued for their beauty, rarity, and durability, whereas borax crystals do not meet these criteria. Borax crystals are formed from the mineral borax, and while they can be aesthetically pleasing, they are not commonly used in jewelry or considered as valuable as traditional gemstones like amethyst, diamonds, and sapphires.

Vinegar has the most acidity among the given substances. Vinegar is a solution of acetic acid in water, which gives it its sour taste and acidic properties. It has a low pH value, typically around 2-3, indicating high acidity. On the other hand, bleach, water, and soapy water are not acidic substances. Bleach is a strong base, water is neutral, and soapy water is slightly basic due to the presence of soap. Therefore, vinegar is the correct answer for the substance with the most acidity.

Polymer is the correct answer because it is a type of molecule that is made up of long chains of repeating small molecules called monomers. This arrangement allows polymers to have unique properties and characteristics. Crystals, hydrogen, and acids do not typically exhibit this type of repeating chain structure.

Glass is not an example of a polymer because it is not made up of repeating units of smaller molecules. Polymers, on the other hand, are large molecules composed of repeating subunits called monomers. Wool, silly putty, and plastic soft drink bottles are all examples of polymers as they are composed of repeating units of smaller molecules.

Chemical reactions involve a change at the molecular level. During a chemical reaction, bonds between atoms are broken and new bonds are formed, resulting in the formation of new molecules with different properties than the original substances. This process involves the rearrangement of atoms and the breaking or formation of chemical bonds, leading to a change in the composition and structure of the substances involved. Therefore, the correct answer is "Chemical".

Soapy water has the most alkalinity because alkalinity refers to the ability of a substance to neutralize acids. Soap is typically made from a combination of fats and alkali, which gives it a high alkalinity. This means that it can effectively neutralize acids, making it more alkaline than tap water, lemon juice, or battery acid.