STANDARD 5a

• Students know reactant atoms and molecules interact to form products with different chemical properties

CHEMICAL REACTIONS• The reactants are the atoms and

molecules that start a chemical change or reaction

• The new substances that form in a chemical change are called products

• During a chemical change or reaction, atoms in the reactants rearrange as chemical bonds break and new bonds form

• The products of a chemical reaction have different chemical and physical properties than the reactants

CHEMICAL REACTIONS55. The reactants of a chemical reaction

haveA chemical properties identical to the productsB chemical properties different from the productsC the same chemical makeup as the productsD no chemical bonds

ANSWER: B

CHEMICAL REACTIONS

56. Which is evidence that a chemical reaction might have occurred?

A release of energy

B change in shape

C similarities in physical properties

D presence of ions

ANSWER: A

CHEMICAL REACTIONS

57. Which of the following statements is true about the reaction shown in the diagram?A The products are identical to the reactantsB The atoms of the product rearrange to form new moleculesC The atoms of the reactants rearrange to form new moleculesD No chemical bonds are broken

ANSWER: C

STANDARD 5b

• Students know the idea of atoms explains the conservation of matter: in chemical reactions the number of atoms stays the same no matter how they are arranged, so their total mass stays the same

CONSERVATION OF MATTER• Conservation of matter states

that during a chemical reaction, matter is neither created nor destroyed

• The total number of atoms stays the same before and after the reaction

CONSERVATION OF MATTER

58. According to the principle of the conservation of matterA reactants have the same mass as the productsB reactants have more mass than the productsC products have less mass than the

reactantsD products have more mass than the

reactants

ANSWER: A

CONSERVATION OF MATTER59. Which equation

shows that the total mass during a chemical reaction stays the same?A 1B 2C 3D 4

ANSWER: C

CONSERVATION OF MATTERN2O5 + H2O → HNO3

60. Berta wants to balance the equation shown above. Which number should she place in front of HNO3 in order to balance the equation?

A 1

B 2

C 3

D 4

ANSWER: B

Chemical Reactions61. According to the

law of conservation of mass, what mass of O2 is generated?

A 8 g

B 16 g

C 200 g

D 216 g

ANSWER: B

STANDARD 5c

• Students know chemical reactions usually liberate heat or absorb heat

CHEMICAL REACTIONS• If a chemical reaction results in the

release of energy, the reaction is called an exothermic reaction

• This energy is often released as heat and light into the surroundings, which becomes warmer

• If a chemical reaction results in a net absorption of energy, the reaction is called an endothermic reaction

• The energy for the reaction is usually absorbed from the surroundings, which becomes cooler

CHEMICAL REACTIONS• The graphs show energy changes in endothermic

and exothermic reactions.• The “bump” in the graph represents the activation

energy, which is the minimum amount of energy required to get the reaction started

Exothermic Reaction Endothermic Reaction

CHEMICAL REACTIONS62. Burning wood is an exothermic

reaction because

A energy is absorbed

B energy is released

C the reaction requires energy to keep going

D Activation energy is not required

ANSWER: B

CHEMICAL REACTIONS63. In an endothermic reaction,

A the products give off heat

B mass is not conserved

C the products have less energy than the reactants

D the products have more energy than the reactants

ANSWER: D

CHEMICAL REACTIONS

64. The graphs show the energy changes that occur during a chemical reaction. Which graph best describes a chemical reaction that absorbs energy?

ANSWER: D

CHEMICAL REACTIONS65. Which of the following is true of both

exothermic and endothermic reactions?

A They absorb heat

B They release heat

C They require some energy to start

D They use more energy than they produce

ANSWER: C

STANDARD 5d

• Students know physical processes include freezing and boiling, in which a material changes form with no chemical reaction

PHYSICAL CHANGES• A physical change differs from a

chemical change in that chemical bonds are neither broken nor formed

• The appearance of the substance will change, but not its chemical makeup

• When water changes from a liquid to a solid, the appearance changes, but the ice and liquid water have the same chemical formula: H2O

Chemical ReactionsFreezing, melting and

boiling are NOT chemical reactions. They are physical

changes.

PHYSICAL CHANGES• A mixture is made of two or more

substances that are together in the same place but are not chemically combined: salad, pizza

• Making a mixture is a physical change because the parts of the mixture can be separated

• A solution is a uniform mixture that has the same properties throughout: salt water

PHYSICAL CHANGES66. A change of state is a physical change

becauseA the parts of the mixture can be separatedB the atoms of the substance form new chemical bondsC the boiling point of the substance changesD the chemical makeup of the substance stays the same

ANSWER: D

PHYSICAL CHANGES67. David stirs a spoonful of sugar into a

glass of lemonade. As he stirs, the sugar disappears. What type of change is occurring?

A chemical change

B creation of matter

C destruction of matter

D physical change

ANSWER: D

PHYSICAL CHANGES

68. During boiling, liquid water turns to water vapor. This is an example of

A physical change

B chemical change

C chemical equation

D chemical formula

ANSWER: A

STANDARD 5e

• Students know how to determine whether a solution is acidic, basic, or neutral

ACIDS AND BASES

• Properties of acids:– Taste sour

– Corrosive

– Conduct electricity

– pH range of 1.0 - 6.9

– Changes blue litmus paper to red

ACIDS AND BASES

• Properties of bases:– Tastes bitter

– Feels slippery

– Conducts electricity

– Corrosive

– pH range of 7.1 – 14.0

– Changes red litmus paper to blue

ACIDS AND BASES

• If the pH of a solution is 7.0 then the solution is considered neutral

• Water has a pH of 7.0

ACIDS AND BASES71. Which of the following things could be

used to determine whether a substance is an acid or a base?A an indicatorB litmus paperC pH meterD all of the above

ANSWER: D

ACIDS AND BASES72. These data indicate that gastric juice is a

A strong acidB strong baseC weak acidD weak baseANSWER: A

ACIDS AND BASES73. A substance that turns red litmus

paper blue is

A an acid

B a base

C an indicator

D a solvent

ANSWER: B

STANDARD 6a

• Students know that carbon, because of its ability to combine in many ways with itself and other elements, has a central role in the chemistry of living organisms

CHEMISTRY OF LIVING THINGS• CARBON - has four valence (outer)

electrons and so it can make four bonds

• Carbon atoms bonded together with single, double, or triple bonds can form straight chains, branched chains, or rings

• Carbon’s ability to form four bonds results in millions of different shaped carbon-based molecules that allow them to have many different functions in living organisms

C

CHEMISTRY OF LIVING THINGS

74. Unlike the atoms of most other elements, carbon atoms have which number of bonding electrons?

A 1

B 2

C 3

D 4

ANSWER: D

CHEMISTRY OF LIVING THINGS

75. Carbon-based molecules have a wide range of chemical properties because they

A have covalent bonds

B have the same shape

C can form many different shapes

D always form straight chains

ANSWER: C

STANDARD 6b

• Students know that living organisms are made of molecules consisting largely of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur

CHEMISTRY OF LIVING THINGS

• An organic compound contains carbon

• Organic compounds are found in all living organisms

• Organic compounds include hydrocarbons, alcohols, organic acids, and polymers

Other Important Atoms in Living Things

Most organic molecules in living things contain

carbon hydrogennitrogen oxygensulfur phosphorus

NCHOPS

Chemistry of Living Things76. Compounds that contain the element

carbon are called

A organic compounds

B polar molecules

C nonpolar molecules

D hydrocarbons

ANSWER: A

Chemistry of Living Things

77. Which chemical formula does not represent an organic compound?

A CH3OH

B NH3

C C6H14

D CHCl3

ANSWER: B

Chemistry of Living Things

78. Which of the following elements is not an important component of organisms?

A nitrogen

B oxygen

C phosphorus

D potassium

ANSWER: D

STANDARD 6c

• Students know that living organisms have many different kinds of molecules, including small ones, such as water and salt, and very large ones, such as carbohydrates, fats, proteins, and DNA

Chemistry of Living Things• Carbohydrates are polymers made of

smaller molecules called glucose. Includes sugars, starch, and cellulose. Provides energy for living organisms

• Proteins are polymers made up of smaller molecules called amino acids. Proteins are used to build and repair body parts

• Lipids are polymers made from three fatty acids and alcohol named glycerol. Lipids include fats, oils, and waxes and are used to store energy for living organisms

• Nucleic acids are very large polymers made from four smaller molecules called nucleotides. Two types: DNA and RNA. Carries genetic information

Chemistry of Living Things

• Smaller molecules that living organisms need to survive include water, vitamins, minerals, and salts

• Most chemical reactions that occur in living things take place in water

• Vitamins and minerals serve as helper molecules in many life processes

• Salts are required for many functions, such as contracting muscle, transmitting nerve impulses, and balancing blood pH

Chemistry of Living Things

79. Which of the following is the smallest molecule?

A protein

B sugar

C salt

D carbohydrate

ANSWER: C

Chemistry of Living Things80. Which molecule is NOT a chemical

used by living organisms?A lipidB nucleic acidC carboxylic acidD protein

ANSWER: C

Chemistry of Living Things

82. Which of the following kinds of chemical compounds does not contain carbon?

A sugar

B lipid

C water

D protein

ANSWER: C