Chemistry: Chemical Reactions

cooking, hair dye, respiration, auto feul

What are 4 examples of chemical reactions?

chemical reaction

The process by which one or more substances change into one or more new substance.

chemical equations

What are chemical reactions represented by?

the law of conservation of mass (matter)

• atoms won’t be created or destroyed in a chemical reaction

• what you start with is what you end with

color, gas formation, precipitate formation, temperature change, color change, odor

What are the 6 indicators of a chemical reaction?

law of conservation of mass

We balance chemical equations to satisfy the _____________.

matter

In a chemical reaction, _________ neither created nor destroyed.

no

Can atoms change their identity (according to the law of conservation of mass)?

yes

According to the law of conservation of mass, will the same number of each type of atom appear on each side of the chemical equation?

symbols and formulas

What do chemical equation us to represent a chemical reaction?

reactants

Parts of a chemical equation: Substances which start the reaction are used up

products

Parts of a chemical equation: substances formed the reaction

subscripts

Parts of a chemical equation: numbers inside the formulas (tells how many atoms/ions are present)

coefficients

Parts of a chemical equation: in balanced equations, numbers written in front of the formula of a substance

→

Symbols used in chemical equations: “yields,” or “produces” (separates reactants from products); indicates the result of a reaction

+

Symbols used in chemical equations: “reacts with," or “produced alongside”; (separates two or more reactants or products)

NR

Symbols used in chemical equations: no reactions takes place when reactants are mixed

(s)

Symbols used in chemical equations: pure substance (reactant or product) is a solid

(l)

Symbols used in chemical equations: pure substance (reactant or product) is a liquid

(g)

Symbols used in chemical equations: pure substance (reactant or product) is a gas

(aq)

Symbols used in chemical equations: aqueous solution (reactant or product is dissolved in water)

synthesis, decomposition, single replacement (displacement), double replacement (displacement), combustion

Name the 5 types of chemical reactions.

4Na+O₂ → 2Na₂O

Practice: __Na + __O₂ → __Na₂O

Ca(OH)₂ + H₂SO₄ → CaSO₄ + 2H₂O

Practice: __Ca(OH)₂ + __H₂SO₄ → __CaSO₄ + __H₂O

Synthesis Reaction

Name the type of chemical reaction: A + B → AB

decomposition reaction

Name the type of chemical reaction: AB → A + B

single replacement reaction

Name the type of chemical reaction: A + BC → AC + B

double replacement reaction

Name the type of chemical reaction: AB + CD → AD + CB

Combustion reaction (with hydrocarbons only)

Name the type of chemical reaction: C₂H₂ + O₂ → CO₂ + H₂O

couple

Synthesis reaction = the _________ reaction

product

In a synthesis reaction, elements combine (react) to form a __________

binary

In a synthesis reaction, you are predicting products for ________ ionic only.

Al + Cl₂ → AlCl₃

Practice Synthesis Reactions: Al + Cl₂ →

K + N₂ → K₃N

Practice Synthesis Reactions: Potassium + nitrogen →

decomposition reaction

• The break-up reaction

• AB → A + B

• Ex: 2HgO (s) → 2Hg (l) + O₂ (g)

Opening a carbonated beverage (carbonic acid breaks down into H₂O and CO₂), Digestion of food (carbs, fats, and proteins breakdown into simpler nutrients), Plant decomposition (photodegradation of leaves into nutrient source)

What are 3 common types of decomposition reactions?

1 reactant; 2; simpler products

Decomposition reaction is the opposite of synthesis; ____ ________ breaks down into ____ or more _______ ________.

binary

Decomposition reactions are predicting products for ________ compounds only.

electrolysis

Sometimes a compound is decomposed by electricity.

electrolysis

water is broken down into its components by __________

hydrocarbon combustion reactions

• the reaction that always has the same products

• CH₄ + 4CO₂ → CO₂ + 2H₂O

oxygen; carbon dioxide; water

A hydrocarbon compound (usually a fuel) burns; burning always requires _________, products of hydrocarbon combustion are always _________ and _______

Burning of candle wax, burning LPG (liquid petroleum gas) too cook, burning of coal or wood, thermal power plants

Name 4 common hydrocarbon combustion reactions.

single replacement (or displacement) reaction

• The choosing a more reactive partner reaction

• Ex: 2K + 2H₂O → 2KOH + H₂

• One compound reacts with an element to form a new compound and a different element.

• A + BC → AC + B

active

In a single replacement reaction, one element only replaces another in a compound if it is more ________.

cation; anion; halogens

In a single replacement reaction, a cation will replace a _______ or an anion will replace a ________. Halogens replace _________.

aqueous solution

Single replacement reactions often take place in an ________ ________.

Double Replacement (or displacement) reactions

• the let’s switch dance partners reaction

• AB + CD → AD + CB

• Ex: K₂CO_3(aq) → 2KCl_(aq) + BaCO_3(s)

2 different compounds

In a double replacement reaction, 2 compounds react to form what?

positive; positive

In a double replacement reaction, the ________ ion of one compound replaces the ________ ion of the other compound.

precipitate; insoluble gas; molecular compound

In a double replacement reaction, one of the products formed will either be a __________ or an _________ _____ that bubbles out of the solution or a _________ ________ (usually water).

dissociation

When the substance has been dissolved in water, an ionic compound is breaking down into its ions (charged substances).

precipitate (s); soluble substance (aq)

When predicting the products of a double replacement reaction, you must identify the substance as a __________ or a _________ _________.