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Ch 11: ORELA General Science: Basics of Chemical Reactions

About This Chapter

Use the video lessons and quizzes in this chapter to help you get ready for questions about the basics of chemical reactions on the ORELA General Science test. Our expert instructors are here to help!

ORELA General Science: Basics of Chemical Reactions - Chapter Summary

Let us help you get ready for the ORELA General Science test with our chapter on the basics of chemical reactions. Our expert instructors have created video lessons that are brief but thorough. These lessons are easy to navigate so you can jump over stuff you know already and concentrate on the areas where you're a bit rusty. Our lessons guide you through topics like:

  • How to balance chemical equations
  • Mole-to-mole ratios in chemical equations
  • Mass-to-mass stoichiometry
  • Relative quantities in a gas or a solution
  • Limiting and excess reactants
  • Reaction and percentage yield
  • Percent composition and empirical formulas
  • Hydrates
  • Endothermic and exothermic reactions

Take the short, multiple-choice quiz following each lesson to help you gain confidence in your skills and find areas that need more work. Each video can be watched as many times as needed.

ORELA General Science: Basics of Chemical Reactions - Chapter Objectives

The NES General Science test is a computer-based multiple-choice test with four main sections. You'll have three hours to complete the test (totaling 150 questions). The Physical Science section, constituting about 37% of the test, is where you're most likely to find questions about chemical reactions. Test creators formatted the test to assess, among other things, your knowledge of chemical formulas, types of chemical bonds, balancing chemical equations using stoichiometry and the mole concept, as well as analyzing and distinguishing various types of chemical reactions. As you can see, our instructors have correlated their lesson topics with these exam objectives. We want you to feel confidently prepared on test day!

9 Lessons in Chapter 11: ORELA General Science: Basics of Chemical Reactions
Chemical Reactions and Balancing Chemical Equations

1. Chemical Reactions and Balancing Chemical Equations

In this lesson, you'll learn how to balance a chemical reaction equation using the conservation of matter law. You'll also learn how to write both word and formula equations, what the subscripts after a letter mean and what the numbers in front of compounds mean.

Mole-to-Mole Ratios and Calculations of a Chemical Equation

2. Mole-to-Mole Ratios and Calculations of a Chemical Equation

Learn what a mole ratio is and how to determine and write the mole ratio relating two substances in a chemical equation in this video lesson. Also, learn to make mole-to-mole calculations and solve problems involving moles of substances.

Mass-to-Mass Stoichiometric Calculations

3. Mass-to-Mass Stoichiometric Calculations

Learn how to set up and make mole to mass, mass to mole and mass to mass stoichiometric calculations. Learn how the ratios of moles helps you compare and make calculations. Learn how to relate mole ratios to molar mass.

Stoichiometry: Calculating Relative Quantities in a Gas or Solution

4. Stoichiometry: Calculating Relative Quantities in a Gas or Solution

In this lesson, learn about molar volume and how to set up and make stoichiometric calculations with gases. Then learn about solution stoichiometry and how to make stoichiometric calculations with solutions.

Limiting Reactants & Calculating Excess Reactants

5. Limiting Reactants & Calculating Excess Reactants

In this lesson, you'll learn what limiting reactant and excess reactant mean and how to determine which reactant is limiting in a chemical reaction when given the amount of each reactant. You'll also discover how to calculate the amount of product produced.

Calculating Reaction Yield and Percentage Yield from a Limiting Reactant

6. Calculating Reaction Yield and Percentage Yield from a Limiting Reactant

Learn what the theoretical yield, actual yield and percent yield are. Given the limiting reactant, learn how to calculate the theoretical reaction yield, which is also known as the ideal reaction yield and percentage yield.

Calculating Percent Composition and Determining Empirical Formulas

7. Calculating Percent Composition and Determining Empirical Formulas

Learn the difference between the empirical formula and chemical formula. Learn how to calculate the percent composition of an element in a compound. Learn how, if given a percent composition, to determine the empirical formula for a compound.

Hydrates: Determining the Chemical Formula From Empirical Data

8. Hydrates: Determining the Chemical Formula From Empirical Data

Learn the definition of a hydrate and an anhydrate in this lesson. Discover how, when given experimental data, you can determine the formula of a hydrate by following simple steps that include finding the moles of hydrate and anhydrate and comparing the two to write the formula.

Endothermic and Exothermic Reactions

9. Endothermic and Exothermic Reactions

Explore a chemical reaction at the molecular level. Learn about exothermic and endothermic reactions, what they look like and what happens when they occur. Understand enthalpy and how you can use it to predict whether a reaction will be exothermic or endothermic.

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