Chemical Reaction Of Respiration Quiz

The balanced chemical equation for the reaction between hydrogen gas (H2) and oxygen gas (O2) to form water (H2O) is 2 H2 + O2 → 2 H2O. This means that for every 2 molecules of hydrogen gas and 1 molecule of oxygen gas, 2 molecules of water are produced.

The given chemical equation represents the decomposition of silver(II) oxide (Ag2O) into its constituent elements, silver (Ag) and oxygen gas (O2). The balanced equation shows that 2 moles of Ag2O decompose to form 4 moles of Ag and 1 mole of O2. Therefore, the correct answer is 4.

The location of an element in the periodic table provides information about its properties. This is because elements in the same group or period tend to have similar chemical and physical properties. For example, elements in the same group have the same number of valence electrons, which determines their reactivity. Additionally, the position of an element in the periodic table can give insights into its atomic size, electronegativity, and ionization energy. Therefore, knowing the location of an element in the periodic table allows us to make predictions about its properties.

The principle of conservation of mass states that mass cannot be created or destroyed in a chemical reaction, only rearranged. This principle holds true for all reactions, regardless of whether they take place in open or closed systems. In an open system, matter can enter or leave the system, but the total mass of the system remains constant. In a closed system, matter is confined and cannot enter or leave, but the principle still applies as the total mass within the system remains constant. Therefore, the principle of conservation of mass is valid for all reactions.

The reactants in the given equation are water and oxygen. This can be determined by looking at the left side of the equation, where water (H2O) and oxygen (O2) are present. The right side of the equation shows the product, which is hydrogen peroxide (H2O2). Reactants are the substances that undergo a chemical reaction to form the products.

A chemical equation that shows the same number of each kind of atom on both sides of the equation is said to be balanced. This means that the total number of atoms of each element is equal on both the reactant and product sides of the equation. This is important because it follows the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction. By balancing the equation, it ensures that the same amount of each element is present before and after the reaction.

When chemical bonds break and new bonds form, it indicates a chemical reaction. In a chemical reaction, the arrangement of atoms is altered, resulting in the formation of new substances with different properties. This process involves the breaking of existing chemical bonds and the formation of new ones, leading to a rearrangement of atoms and the creation of new molecules or compounds. This is different from a physical change, where no new substances are formed and the arrangement of atoms remains the same.

Reactants are the substances that are present on the left side of a chemical equation. They are the starting materials that undergo a chemical reaction to form products. In a chemical equation, reactants are represented by their chemical formulas or names. They are typically written before the arrow, which represents the direction of the reaction. Reactants are consumed during the reaction and their chemical bonds are broken and rearranged to form new substances, which are the products of the reaction.

The correct answer is "the study of matter and how matter changes." This answer accurately describes the field of chemistry, which involves the study of the composition, properties, and behavior of matter, as well as the changes that matter undergoes during chemical reactions. Chemistry encompasses a wide range of topics, including the structure of atoms and molecules, the interactions between different substances, and the principles that govern chemical reactions. By studying chemistry, scientists can gain a deeper understanding of the world around us and develop new materials, medicines, and technologies.

An endothermic reaction is characterized by the absorption of energy in the form of heat. This means that the reaction requires an input of heat energy to occur. In an endothermic reaction, the products have higher energy than the reactants, resulting in a decrease in temperature of the surroundings as heat is taken in. This is opposite to an exothermic reaction, where heat is released to the surroundings. Combustion refers to a specific type of exothermic reaction involving the reaction of a substance with oxygen, while "unbalanced" does not accurately describe the energy absorption in a chemical reaction.

The principle of conservation of mass in chemical reactions states that matter is not created or destroyed. This means that the total mass of the reactants before the reaction is equal to the total mass of the products after the reaction. In other words, atoms are rearranged and combined in different ways, but no atoms are lost or gained during a chemical reaction.

In a chemical formula, the number placed below an element's symbol is called a subscript. Subscripts are used to indicate the number of atoms of each element in a molecule or compound. They are written in a smaller font below the element's symbol. Subscripts are important because they help us understand the ratio of elements present in a compound and determine the chemical formula.

Synthesis and decomposition can be considered opposites because synthesis is the process of combining simpler substances to form a more complex substance, while decomposition is the process of breaking down a complex substance into simpler substances. In synthesis, new bonds are formed, whereas in decomposition, existing bonds are broken. Therefore, these two processes have opposite effects on the complexity of substances.

The given reaction, FeS + 2HCl -> FeCl2 + H2S, is an example of a replacement reaction. In this type of reaction, one element in a compound is replaced by another element. In this case, the iron (Fe) in FeS is replaced by the chlorine (Cl) in HCl, forming FeCl2. Similarly, the hydrogen (H) in HCl is replaced by the sulfur (S) in FeS, forming H2S. Therefore, the correct answer is replacement.

The production of one or more new substances is the only sure evidence for a chemical reaction because it signifies a chemical change. In a chemical reaction, the reactants undergo a rearrangement of their atoms to form new substances with different chemical properties. This is different from physical changes where the substances may undergo a change in state or appearance but do not form new substances. Therefore, the production of new substances is a clear indication that a chemical reaction has occurred.

The correct answer is "formula" because CaCO3 represents the chemical formula for calcium carbonate. A chemical formula is a shorthand representation of the elements present in a compound, using their symbols and subscripts to indicate the ratio of atoms. In this case, Ca represents calcium, C represents carbon, and O represents oxygen, with the subscript 3 indicating that there are three oxygen atoms for every one calcium and carbon atom.

The given reaction represents a synthesis reaction. In a synthesis reaction, two or more substances combine to form a single compound. In this case, nitrogen gas (N2) and hydrogen gas (H2) combine to form ammonia (NH3).

Metals contain the most elements among the given options. Metals are a large group of elements that are typically shiny, malleable, and good conductors of heat and electricity. They make up the majority of the periodic table and include elements such as iron, copper, and gold. Nonmetals, metalloids, and transition elements are smaller groups compared to metals. Nonmetals are poor conductors of heat and electricity, metalloids have properties of both metals and nonmetals, and transition elements are a specific subset of metals found in the middle of the periodic table.

In every chemical reaction, energy is involved and can either be released or absorbed. This is because chemical reactions involve the breaking and formation of bonds between atoms, which requires the input or release of energy. Therefore, energy is an essential component of chemical reactions and is always involved in the process.

In a chemical equation, the numbers that appear in front of a chemical formula represent the number of molecules or atoms of each substance involved in the reaction. These numbers, known as coefficients, provide information about the ratio in which the substances react and the number of particles present in the reaction. By indicating the number of molecules or atoms, the coefficients help balance the equation and ensure that the law of conservation of mass is followed.