1.
Which equation listed below is an example of a synthesis reaction?
Correct Answer
A. A + B yields AB
Explanation
A synthesis reaction is a type of chemical reaction in which two or more substances combine to form a single, more complex substance. In the given options, the equation "A + B yields AB" represents a synthesis reaction because two individual substances (A and B) combine to form a more complex substance (AB).
2.
Which equation listed below is an example of a decomposition reaction?
Correct Answer
B. AB yields A + B
Explanation
The equation AB yields A + B is an example of a decomposition reaction because it represents the breaking down of a compound (AB) into its individual elements (A and B).
3.
Which equation listed below is an example of a single replacement reaction?
Correct Answer
C. AB + C yields AC + B
Explanation
The equation "AB + C yields AC + B" is an example of a single replacement reaction because one element (C) replaces another element (B) in the compound AB, forming a new compound AC.
4.
Which equation listed below is an example of a double replacement reaction?
Correct Answer
D. AB + CD yields AC + BD
Explanation
The equation AB + CD yields AC + BD is an example of a double replacement reaction. In a double replacement reaction, the cations and anions of two different compounds switch places to form two new compounds. In this equation, the cation AB and the anion CD switch places to form the compounds AC and BD.
5.
The _____________ are on the left side of the yield sign in a chemical reaction and are described as the "ingredients" in a chemical reaction.
Correct Answer
A. Reactants
Explanation
In a chemical reaction, the reactants are the substances that undergo a chemical change to form new substances called products. They are placed on the left side of the yield sign, indicating that they are the starting materials or "ingredients" in the reaction. Therefore, the correct answer is Reactants.
6.
The _____________ are on the right side of the yield sign in a chemical reaction and are described as what is produced in a chemical reaction.
Correct Answer
B. Products
Explanation
In a chemical reaction, the products are the substances that are formed as a result of the reaction. They are located on the right side of the yield sign. The reactants, on the other hand, are the substances that undergo the chemical changes and are located on the left side of the yield sign. Therefore, the correct answer is "Products".
7.
The arrow in a chemical reaction means all of the following except
Correct Answer
D. Attaches to
Explanation
The arrow in a chemical reaction is used to represent the direction of the reaction, indicating the conversion of reactants into products. It does not imply that one substance "attaches to" another substance, but rather shows the transformation of the reactants into the products. Therefore, "attaches to" is not a valid interpretation of the arrow in a chemical reaction.
8.
The Law of Conservation of Matter states
Correct Answer
A. Matter cannot be created or destroyed in a chemical reaction
Explanation
The Law of Conservation of Matter states that matter cannot be created or destroyed in a chemical reaction. This means that the total mass of the reactants must be equal to the total mass of the products. While matter can undergo physical and chemical changes, the total amount of matter remains constant. This principle is a fundamental concept in chemistry and is supported by numerous experimental observations.
9.
Painting a pencil red is a chemical change.
Correct Answer
B. False
Explanation
Painting a pencil red is not a chemical change, but a physical change. Chemical changes involve a rearrangement of atoms and the formation of new substances, while physical changes only alter the appearance or state of a substance without changing its chemical composition. In this case, painting a pencil red only changes its color, but the chemical composition of the pencil remains the same. Therefore, the correct answer is false.
10.
Check ALL of the properties listed below that are chemical properties.
Correct Answer(s)
A. Flammability
B. Combustability
D. Affected by light
E. Ability to rust
Explanation
Flammability and combustibility are chemical properties because they describe the ability of a substance to undergo a chemical reaction, specifically combustion. Being affected by light is also a chemical property as it can cause a substance to undergo a chemical change, such as photochemical reactions. The ability to rust is also a chemical property as it involves a chemical reaction, specifically the oxidation of a metal in the presence of oxygen and water. However, flexibility is not a chemical property as it is a physical property that describes the ability of a substance to bend or deform without breaking.
11.
Select ALL the answers listed below that are examples of a physical change.
Correct Answer(s)
A. Color change
D. Water changing to steam
E. Wood being shreded
Explanation
The given answers "color change," "water changing to steam," and "wood being shredded" are examples of physical changes. A physical change is a change in the physical properties of a substance, such as its shape, size, or state, without altering its chemical composition. In the case of "color change," it implies a change in the appearance of the substance without any chemical reaction. "Water changing to steam" is a phase change from a liquid to a gas, which is a physical change. "Wood being shredded" involves breaking down the wood into smaller pieces, which is also a physical change as it does not alter the chemical composition of wood.
12.
Select ALL the choices below that are examples of a chemical change.
Correct Answer(s)
A. Iron rusting
B. Color change as an indicator
C. Baking soda fizzing/bubbling when mixed with vinegar
Explanation
Iron rusting, color change as an indicator, and baking soda fizzing/bubbling when mixed with vinegar are all examples of chemical changes. Iron rusting is a chemical reaction that occurs when iron reacts with oxygen in the presence of water or moisture. Color change as an indicator is also a chemical change because it involves a chemical reaction that causes a change in the color of the indicator. Baking soda fizzing/bubbling when mixed with vinegar is a chemical change as it involves a reaction between the two substances, resulting in the release of carbon dioxide gas.
13.
Select ALL the choices below that are examples of a physical property.
Correct Answer(s)
A. Bitter taste
B. Odor
D. Melting point
Explanation
The given answer choices, bitter taste, odor, and melting point, are all examples of physical properties. A physical property is a characteristic of a substance that can be observed or measured without changing the substance's chemical composition. Bitter taste and odor are sensory properties that can be perceived by our senses. Melting point is the temperature at which a substance changes from a solid to a liquid state. These properties do not involve any chemical reactions or changes in the composition of the substance, making them physical properties.
14.
Which of the following best describes something that has mass and takes up space?
Correct Answer
B. Matter
Explanation
Matter is the correct answer because it refers to anything that has mass and occupies space. In the context of physics and chemistry, matter is the fundamental substance that makes up all physical objects. It can exist in different states such as solid, liquid, or gas, and can undergo various changes, such as chemical reactions. Therefore, matter encompasses all physical substances and is a broad term that encompasses the concept of mass and occupying space.
15.
The study of matter and how it changes is best described as
Correct Answer
A. Chemistry
Explanation
The study of matter and how it changes is best described as chemistry because chemistry is the branch of science that deals with the composition, structure, properties, and reactions of matter. It involves the study of atoms, molecules, elements, compounds, and the various changes that matter can undergo, such as chemical reactions. Chemistry helps us understand the behavior of substances, their interactions, and how they can be manipulated or transformed.
16.
A change in matter that results in something new is called
Correct Answer
C. Chemical change
Explanation
A change in matter that results in something new is called a chemical change. This type of change involves a rearrangement of atoms or molecules, resulting in the formation of new substances with different properties. It often involves the breaking and forming of chemical bonds, leading to a transformation at the molecular level. Examples of chemical changes include combustion, rusting, and digestion.
17.
A characteristic that can be observed without changing the substance is called a ______________.
Correct Answer
A. pHysical property
Explanation
A physical property is a characteristic that can be observed without changing the substance. This means that the substance remains the same even when the property is observed. Examples of physical properties include color, density, odor, and melting point.
18.
A(n) _____________ chemical reaction occurs when heat is absorbed into a chemical reaction.
Correct Answer
C. Endothermic
Explanation
Endothermic chemical reactions occur when heat is absorbed into the reaction. In these reactions, the reactants absorb energy from the surroundings, usually in the form of heat, causing the temperature of the surroundings to decrease. This is in contrast to exothermic reactions, where heat is released into the surroundings. Endothermic reactions often require an input of energy to proceed, and they are commonly observed in processes such as photosynthesis, evaporation, and the melting of ice.
19.
A(n) _____________ chemical reaction occurs when heat is released from a chemical reaction.
Correct Answer
D. Exothermic
Explanation
An exothermic chemical reaction occurs when heat is released from a chemical reaction. This means that the reactants have more energy than the products, and the excess energy is released in the form of heat.
20.
Select ALL the options listed below that are a sign of a chemical reaction.
Correct Answer(s)
A. Temperature increase
B. Temperature decrease
C. Light is produced
F. Fizzing/bubbling
Explanation
When a chemical reaction occurs, it can be indicated by several signs. An increase or decrease in temperature suggests that energy is being released or absorbed during the reaction. The production of light is a clear indication of a chemical reaction taking place. Fizzing or bubbling occurs when a gas is being released as a product of the reaction. Therefore, all of these options are signs of a chemical reaction occurring.
21.
A characteristic of a substance that describes its ability to change into something new is called a(n)
Correct Answer
B. Chemical property
Explanation
A chemical property is a characteristic of a substance that describes its ability to change into something new. Unlike physical properties, which describe the substance's appearance or state, chemical properties involve the substance's composition and its ability to undergo chemical reactions. Chemical properties can include flammability, reactivity with other substances, and stability.