Physical Science Ch 10

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Chapter 10 Chemical Compounds

Table of Contents

Section 1 Ionic and Covalent Compounds

Section 2 Acids and Bases

Section 3 Solutions of Acids and Bases

Section 1 Ionic and Covalent CompoundsChapter 10

What You Will Learn

• The physical properties of a compound are determined by the type of bonding in the compound.

• Ionic compounds tend to be brittle, have high melting points, dissolve in water, and often conduct electric current in solution.

• Many covalent compounds tend to be insoluble in water, have low melting points, are not water soluble, and often do not conduct electric current in solution.

Ionic Compounds and Their Properties

• Compounds can be grouped by the kind of chemical bond they have. A chemical bond is an interaction that holds atoms or ions together.

• Bonding happens between the valence electrons of different atoms. Valence electrons are electrons in the outermost energy level of an atom. The type of compound that forms depends on what happens to the valence electrons.

Ionic Compounds and Their Properties, continued• An ionic bond is an attraction between oppositely

charged ions.

• Compounds that have ionic bonds are called ionic compounds. Ionic compounds can form when atoms transfer electrons.

Ionic Compounds and Their Properties, continued• Ionic compounds tend to be brittle solids at room

temperature. Their ions are arranged in a repeating three-dimensional pattern called a crystal lattice, which often breaks apart when hit.

• Ionic compounds have high melting points, are highly soluble in water, and often conduct an electric current in solution.

Chemical CompoundsChapter 10

Covalent Compounds and Their Properties

• Covalent compounds are compounds that form when atoms share electrons. A covalent bond forms as a result of this sharing of electrons.

• A molecule is the smallest particle into which a covalently bonded compound can be divided and still be the same compound.

Covalent Bonding

Covalent Compounds and Their Properties, continued• Properties of covalent compounds are very different

from the properties of ionic compounds.

• Many covalent compounds have low melting points, do not dissolve in water, and do not conduct an electric current in solution.

Section 2 Acids and BasesChapter 10

What You Will Learn

• An acidic solution has an increased number of hydronium ions. A basic solution has an increased number of hydroxide ions.

• Acids are sour, react with many metals, conduct electric current, and change the color of indicators.

• Bases are bitter, feel slippery, conduct electric current, and change the color of indicators.

Acids and Their Properties

• An acid is any compound that increases the number of hydronium ions, H3O+, when dissolved in water.

• Acids have a sour flavor. Many acids are corrosive, which means that they destroy body tissue, clothing, and many other things.

Acids and Their Properties, continued

• Acids change the colors of indicators, such as litmus paper and bromthymol blue. An indicator is a compound that can reversibly change color depending on conditions.

• Bromthymol blue turns yellow in the presence of an acid. Blue litmus paper turns red when an acid is added.

Acids and Their Properties, continued

• Acids react with some metals to make hydrogen gas.

• Acids conduct an electric current when in solution.

• Acids are used for industrial purposes and in household products.

Properties of Acids

Bases and Their Properties

• A base is any compound that increases the number of hydroxide ions, OH-, when dissolved in water. Hydroxide ions give bases their properties.

• Bases have a bitter flavor and a slippery feel. Like acids, many bases are corrosive.

Bases and Their Properties, continued

• Bromthymol blue turns a darker blue when a base is added to it. Red litmus paper turns blue when a base is added.

• Bases conduct an electric current when in solution.

• Bases are useful as cleaning agents and antacids.

Properties of Bases

Section 3 Solutions of Acids and BasesChapter 10

What You Will Learn

• Every molecule of a strong acid or a strong base produces ions in solution. Only a few molecules of a weak acid or a weak base form ions.

• When an acid reacts with a base, a salt forms.

• The pH scale is used to determine if a solution is acidic, basic, or neutral.

• Indicators and pH meters can measure pH.

Strengths of Acids and Bases

• Acids and bases can be strong or weak.

• In a strong Acid all the molecules break apart to form hydronium ions (H3O+)

• In a strong Base all the molecules break apart to form hydroxide ions (OH-)

Strengths of Acids and Bases, continued

• In a weak acid only a few molecules break apart, making only a few hydronium ions. (H3O+)

• In a weak base only a few molecules break apart, making only a few hydroxide ions. (OH-)

Strengths of Acids and Bases, continued

• When all the molecules of an base break apart in water to form ions, the base is a strong base.

• When only a few molecules of a base break apart in water to form ions, the base is a weak base.

Strength and Weakness of Acids and Bases

Acids, Bases, and Neutralization

• The pH is a value from 1 to 14 that is used to express the acidity or basicity (alkalinity) of a system.

• The pH measures the hydronium ion concentration in the solution.

• A solution that has a pH of 7 is neutral. • Basic solutions have a pH greater than 7. • Acidic solutions have a pH less than 7.

• When an acid neutralizes a base, a salt and a water are produced. A salt is an ionic compound formed from the positive ion of a base and the negative ion of an acid.

• Sodium chloride, or table salt, is only one example of a large group of compounds called salts. Salts have many uses in industry and in homes.

Chapter 10 Chemical Compounds

Use the terms below to complete the concept map on the next slide.

a basepHsalt

an acidneutral

Concept Map

Chemical Compounds Chapter 10

End of Chapter 10 Show

Chapter 10 Standards Assessment

1. In the sentence “Some compounds form solids by creating a crystal structure,” what does the word structure mean?A. the arrangement of parts of the compoundB. a building that has been put together from many

partsC. a system made up of parts functioning as a wholeD. a part of a body or organism, such as a tissue or

an organ

1. In the sentence “Some compounds form solids by creating a crystal structure,” what does the word structure mean?A. the arrangement of parts of the compoundB. a building that has been put together from many

partsC. a system made up of parts functioning as a wholeD. a part of a body or organism, such as a tissue or

an organ

2. Identify the correct meaning of the word elements in the following sentence: “Water is made up of the gaseous elements hydrogen and oxygen.”A. natural habitats or environmentsB. parts of appliances that conduct heatC. causes or factors leading to a resultD. substances that cannot be broken down into

simpler substances

2. Identify the correct meaning of the word elements in the following sentence: “Water is made up of the gaseous elements hydrogen and oxygen.”A. natural habitats or environmentsB. parts of appliances that conduct heatC. causes or factors leading to a resultD. substances that cannot be broken down into

simpler substances

3. In the sentence “Compounds have properties that are different from their constituent elements,” what does the word constituent mean?A. a person who lives in a certain area and votes

thereB. one of the words or phrases used in a sentenceC. one of the parts that make up a materialD. a person who appoints another person to act for

3. In the sentence “Compounds have properties that are different from their constituent elements,” what does the word constituent mean?A. a person who lives in a certain area and votes

thereB. one of the words or phrases used in a sentenceC. one of the parts that make up a materialD. a person who appoints another person to act for

4. Which of the following words is the noun form of the word neutral?A. neutralityB. neuterC. neutronD. neutralize

5. What type of compound increases the number of hydronium ions when dissolved in water?A. an acidB. a baseC. an indicatorD. hydrogen gas

6. A compound dissolved in water turns red litmus paper blue and changes the indicator bromthymol blue to dark blue. What kind of compound is it?A. an acidB. waterC. table saltD. a base

7. The ions in an ionic compound are arranged in a repeating three-dimensional pattern called a(n)A. ionic solution.B. chemical bond.C. valence electron.D. crystal lattice.

8. What factor does the pH scale measure?A. the degree of neutralization between acids and

basesB. the concentration of hydroxide ions in a solutionC. the number of salt molecules present in a solutionD. the concentration of hydronium ions in a solution

8. What factor does the pH scale measure?A. the degree of neutralization between acids and

basesB. the concentration of hydroxide ions in a solutionC. the number of salt molecules present in a solutionD. the concentration of hydronium ions in a solution

Use the table below to answer the next question.

9. Which of the compounds in the table above is most likely a covalent compound?A. compound AB. compound BC. compound CD. compound D

Use the table below to answer the next question.

10. Which solution listed in the table above is the most acidic?A. solution AB. solution BC. solution CD. solution D

11. Under what conditions are particles of covalent compounds formed?A. oppositely-charged ions transfer electrons and

form a bondB. two or more atoms share electronsC. an atom of a noble gas bonds with an atom of a

transition metalD. two metal atoms form a bond

11. Under what conditions are particles of covalent compounds formed?A. oppositely-charged ions transfer electrons and

form a bondB. two or more atoms share electronsC. an atom of a noble gas bonds with an atom of a

transition metalD. two metal atoms form a bond

12. Atoms may combine in chemical reactions to formA. elements.B. electrons.C. neutrons.D. compounds.

13. Two atoms of hydrogen have different masses. Which of the following best explains this phenomenon?A. The atoms are ionic compounds of hydrogen.B. One atom has more protons than the other.C. The two atoms are different isotopes of hydrogen.D. The atoms have different atomic numbers.

14. According to the periodic table, which of the following elements is a transition metal?A. titaniumB. magnesiumC. aluminumD. tin

15. The chemical formula for two molecules of glucose is shown below. Which part of the formula is the coefficient?A. AB. BC. CD. D

Physical Science Ch 10

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