BasicsofChemRxns.pptx

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Describing Chemical Reactions

On May 6, 1937, the huge airship

Hindenburg erupted into a fireball. Within a short time, 210,000 cubic meters of hydrogen had burned and the airship was destroyed. The

chemical reaction that occurred is “hydrogen combines with oxygen to produce water.” You will learn to

represent this chemical reaction by a chemical equation.

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Describing Chemical

Reactions >

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Writing Chemical Equations

Writing Chemical Equations

How do you write a word equation?

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Reactions >

Word Equations

To write a word equation, write the

names of the reactants to the left of the arrow separated by plus signs; write the names of the products to the right of the arrow, also separated by plus signs.

Reactant + Reactant  Product + Product

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Reactions >

Methane + Oxygen  Carbon dioxide + Water

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Reactions >

iron + oxygen  iron(III) oxide

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Reactions >

Hydrogen Peroxide  Water and Oxygen

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Reactions >

Chemical Equations

A chemical equation is a representation of a chemical reaction; the formulas of the reactants (on the left) are connected by an arrow with the formulas of the products (on the right).

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Reactions >

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How do you write a skeleton equation?

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Reactions >

Write the formulas of the reactants to the left of the yields sign (arrow) and the formulas of the products to the right.

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Reactions >

A skeleton equation is a chemical equation that does not indicate the relative amounts of the reactants and products.

Here is the equation for rusting:

Fe + O₂  Fe₂O₃

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Reactions >

A catalyst is a substance that speeds up the reaction but is not used up in the reaction.

Without Catalyst With Catalyst

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Reactions >

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Reactions >

Animation 12

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Reactions >

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Balancing Chemical Equations

Balancing Chemical Equations

What are the steps in writing a balanced chemical equation?

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Reactions >

To write a balanced chemical equation, first write the skeleton equation. Then use coefficients to balance the equation so that it obeys the law of conservation of mass.

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Reactions >

This is a balanced equation for making a bicycle. The numbers are called coefficients—small

whole numbers that are placed in front of the formulas in an equation in order to balance it.

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Reactions >

A chemical reaction is also described by a

balanced equation in which each side of the

equation has the same number of atoms of each element and mass is conserved.

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Reactions >

Simulation 11

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Practice Problems for Conceptual Problem 11.2

Problem Solving 11.4 Solve Problem

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Practice Problems for Conceptual Problem 11.2

Problem Solving 11.6 Solve Problem

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Section Quiz

-or-Continue to: Launch:

Assess students’ understanding of the concepts in Section 11.1.

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11.1 Section Quiz.

1. Propane gas reacts with oxygen to produce water vapor and carbon dioxide. Choose the correct word equation for this reaction.

a. propane + carbon dioxide  water + oxygen

b. propane + oxygen + water  carbon dioxide

c. propane + oxygen + water + carbon dioxide

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Slide 36 of 37 2. Which of the following is a skeleton equation?

a. H₂ + CO  CH₃OH

b. 2H₂ + CO  CH₃OH

c. 2H₂ + CO₂  CH₃OH

d. hydrogen + carbon monoxide  methanol

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Slide 37 of 37 3. What coefficient for H₂SO₄ is required to

balance the following equation?

Ca₃(PO₄)₂ + ____ H₂SO₄  3CaSO₄ + 2H₃PO₄

a. 1

b. 2

c. 3

d. 4

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