Chemical Reactions End-of-Unit Assessment

What is an endothermic reaction?

• A chemical reaction that releases energy into its surroundings.

• A chemical reaction that absorbs energy from its surroundings, usually in the form of heat.

• A chemical reaction that occurs spontaneously without energy input.

• A chemical reaction that only occurs at high temperatures.

How do the properties of substances relate to their atomic structure?

• The properties of substances are solely determined by their temperature.

• The properties of substances are influenced by the arrangement and types of atoms in their structure.

• The properties of substances are unrelated to their atomic structure.

• The properties of substances depend only on their molecular weight.

What is an example of a chemical reaction?

• The mixing of vinegar and baking soda, which produces carbon dioxide gas.

• Boiling water to produce steam.

• Melting ice to form water.

• Mixing salt and water to create a saline solution.

What is meant by 'repeating groups of atoms'?

• The arrangement of atoms that form the basic unit of a substance, which can be repeated to create larger structures.

• A random collection of atoms with no specific arrangement.

• A single atom that cannot be divided further.

• A group of atoms that only exists temporarily during a chemical reaction.

What is the law of conservation of mass?

• The law of conservation of mass states that mass can be created in a chemical reaction.

• The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction; the total mass of reactants equals the total mass of products.

• The law of conservation of mass states that the mass of products is always greater than the mass of reactants.

• The law of conservation of mass states that mass can be transformed into energy in a chemical reaction.

What is a chemical reaction?

• A process where substances are mixed without any change.

• A process in which substances (reactants) undergo a transformation to form new substances (products) with different properties.

• A method of measuring the weight of substances before a reaction.

• A technique used to separate mixtures into their individual components.

What are reactants in a chemical reaction?

• Substances that are produced as a result of a chemical reaction.

• Starting substances that undergo change during a chemical reaction.

• Elements that do not participate in the reaction.

• Byproducts that are formed after the reaction is complete.

What is the difference between a physical change and a chemical change?

• A physical change alters the form of a substance without changing its chemical composition.

• A chemical change alters the form of a substance without changing its chemical composition.

• A physical change results in the formation of new substances.

• A chemical change does not affect the physical properties of a substance.

What is an exothermic reaction?

• A chemical reaction that absorbs energy from its surroundings.

• A chemical reaction that releases energy to its surroundings, usually in the form of heat.

• A reaction that occurs only in the presence of light.

• A reaction that produces gas as a byproduct.

What role do diagrams play in understanding chemical reactions?

• Diagrams are used to represent chemical equations only.

• Diagrams help visualize the arrangement of atoms in reactants and products, aiding in the understanding of chemical transformations.

• Diagrams are not useful in chemistry and are often ignored.

• Diagrams only show the final products of a reaction without any details.