Correct Answer: B

Rationale: A balanced equation is one where the number of each type of atom is the same on both sides, fulfilling the law of conservation of mass. This principle ensures that the total number of atoms of each element is equal in both reactants and products, signifying that no atoms are created or destroyed, but rather rearranged.
Choice A is incorrect because a balanced equation has equal numbers of atoms in the reactants and products.
Choice C is incorrect as a balanced equation includes both reactants and products.
Choice D is incorrect because coefficients are essential in balancing equations by adjusting the number of atoms present.

Correct Answer: B

Rationale: Alloys are mixtures of two or more metals, combining their properties to create materials with enhanced characteristics. Examples of alloys include bronze (copper and tin) and steel (iron and carbon). Alloys are commonly used in various industries due to their improved strength, durability, and other desirable qualities. Solutions (
Choice
A) refer to a homogeneous mixture of two or more substances, where one substance is dissolved in another. Compounds (
Choice
C) are substances composed of two or more elements chemically combined in fixed proportions. Suspensions (
Choice
D) are heterogeneous mixtures where particles are dispersed but can settle out over time.

Correct Answer: B

Rationale: The correct answer is B: "-2". Oxygen usually exhibits an oxidation state of -2 in most compounds. This is due to oxygen's high electronegativity, which causes it to attract electrons, leading to the gain of two electrons in chemical reactions.
Choice A (-1) is incorrect because oxygen rarely has an oxidation state of -1 in compounds.
Choice C (0) is incorrect as oxygen does not usually have an oxidation state of zero in compounds.
Choice D (-3) is incorrect as oxygen does not commonly have an oxidation state of -3 in compounds.

Correct Answer: B

Rationale: Glycogen is classified as animal starch, not plant starch. It is the storage form of glucose in animals, primarily found in the liver and muscles.
Choice A (Plant starch) is incorrect because glycogen is not derived from plants.
Choice C (Glucose) is incorrect as glucose is a monosaccharide and not a type of starch.
Choice D (Cellulose) is incorrect as cellulose is a structural polysaccharide found in plant cell walls, not the same as glycogen.

Correct Answer: B

Rationale: Oxygen typically has an oxidation number of -2 in compounds because it tends to gain electrons. This is due to its high electronegativity, which leads to oxygen attracting electrons towards itself in a chemical bond.
Choice A (2) is incorrect because oxygen doesn't have a +2 oxidation number in compounds.
Choice C (0) is incorrect as oxygen rarely has an oxidation number of 0 in compounds.
Choice D (-1) is incorrect as oxygen's oxidation number in compounds is typically -2, not -1.