Chemistry Chapter 8 Flashcards

Questions and Answers

What is a chemical equation?

An equation that represents, with symbols and formulas, the identities and relative molecular or molar amounts of the reactants and products in a chemical reaction.

The evolution of heat and light is not an indication of a chemical reaction.

False

What is a precipitate?

A solid that is produced as a result of a chemical reaction in solution and that separates from the solution.

Which of the following are characteristics of chemical equations? (Select all that apply)

The same number of atoms of each element must appear on each side. Signup and view all the answers

What does a coefficient represent in a chemical equation?

A small whole number that appears in front of a formula in a chemical equation. Signup and view all the answers

What is a word equation?

An equation in which the reactants and products in a chemical reaction are represented by words. Signup and view all the answers

What symbol indicates that reactants yield products in a chemical equation?

→ Signup and view all the answers

Name two examples of diatomic molecules.

Hydrogen (H₂) and Oxygen (O₂). Signup and view all the answers

What is the process of balancing an equation?

The process of adjusting the relative amounts of reactants and products to satisfy the law of conservation of mass. Signup and view all the answers

A balanced formula equation has the same number of atoms of each element on both sides.

True Signup and view all the answers

What does the symbol (s) represent in a chemical equation?

A reactant or product in the solid state. Signup and view all the answers

What does a catalyst do in a chemical reaction?

It changes the rate of a chemical reaction but can be recovered unchanged. Signup and view all the answers

What is a synthesis reaction?

A chemical reaction in which two or more substances combine to form a new compound. Signup and view all the answers

What characterizes a decomposition reaction?

A chemical reaction in which a single compound undergoes a reaction that produces two or more simpler substances. Signup and view all the answers

Define electrolysis.

The decomposition of a substance by an electric current. Signup and view all the answers

What does a double-displacement reaction involve?

It involves the exchange of ions between two compounds to form two new compounds. Signup and view all the answers

What type of reaction releases energy in the form of light and heat?

Combustion reaction. Signup and view all the answers

Study Notes

Chemical Equations

A chemical equation uses symbols and formulas to represent reactants and products in a reaction.
It must depict known facts, ensuring all reactants and products are identified correctly.

Indications of a Chemical Reaction

Signs include the release of energy (heat and light), production of gas, formation of a precipitate, and color changes.

Precipitate

A precipitate is a solid that forms from a chemical reaction in a solution and separates from the liquid.

Characteristics of Chemical Equations

Recognize the importance of correct formulas for each substance.
The law of conservation of mass dictates that the same number of each type of atom must be present on both sides of the equation.

Coefficient

A coefficient is a whole number in front of a formula in a chemical equation, indicating the relative number of moles; if absent, it is understood to be one.

Types of Equations

A word equation expresses reactants and products in word form.
A formula equation represents them by their chemical symbols.

Reaction Symbols

The arrow (→) indicates that reactants yield products.
A reversible reaction is depicted with two arrows (← →).

States of Matter in Reactions

(s) denotes a solid, (l) a liquid, (aq) an aqueous solution, and (g) a gas.
Symbols like ↓ and ↑ indicate the formation of a precipitate or gaseous products, respectively.

Catalysts and Reactions

Catalysts are substances altering the reaction rate but remain unchanged. They are indicated in the equation, often over the reaction arrow.
Electrolysis refers to decomposing a substance using electric current.

Types of Chemical Reactions

Synthesis reaction: A + X → AX; two or more substances combine.
Decomposition reaction: AX → A + X; a single compound breaks down.
Single-displacement reaction: A + BX → AX + B; one element replaces another.
Double-displacement reaction: AX + BY → AY + BX; ions exchange places in solution.
Combustion reaction: Combines with oxygen, producing energy, often with water as a product.

Activity Series

An activity series ranks elements by their reactivity, affecting how they replace each other in reactions. More active elements can replace less active ones in single-displacement reactions.

Balancing Chemical Equations

Balancing involves adjusting coefficients to equalize the number of atoms of each element on both sides of the equation, maintaining the law of conservation of mass.

Important Notes

Use coefficients for balancing; never alter subscripts.
Adjust oxygen and hydrogen last when balancing reactions.

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Description

Test your knowledge of Chemical Equations and Reactions with these flashcards. Learn key terms and definitions that are essential for understanding the fundamentals of chemical reactions. Perfect for students studying chemistry.