Science Standards Review Matter a Distinguish between atoms

Science Standards Review: Matter

a. Distinguish between atoms and molecules. Atoms—smallest unit of any element Protons • Positively charged • Found in the nucleus • Determines the type of element Neutrons • No electrical charge (neutral) • Found in the nucleus Electrons • Negatively charged particles • Found outside the nucleus in electron clouds

Molecule—two or more atoms joined in a definite ratio (ex. H 2 O, C 6 H 12 O 6, O 3)

Mini Review Which of the following pictures represents atoms rather than molecules? Which element has 3 protons? a. Hydrogen (H) b. Oxygen (O) c. Lithium (Li) d. Nitrogen (N)

If the dartboard above is used to model an atom, which dart indicates where the protons and neutrons are located? A Dart W B Dart X C Dart Y D Dart Z

In the equation below, how many molecules of water are present? a. 1 b. 2 c. 3 d. 4 How many molecules of methane? a. 1 b. 2 c. 3 d. 4

What do water, aluminum, redwood trees, and valley quail all have in common? A They are all pure elements. B They are all made of cells. C They are all living creatures. D They are all made of atoms Which of the following represents a molecule? a. H b. He c. O 2 d. Cl

The positive subatomic particle that identifies which element it is called a a. Proton b. Neutron c. Electron d. Nucleus The negatively charged subatomic particle that is involved in bonding with other atoms to make molecules is called a____. a. Proton b. Neutron c. Electron d. Nucleus

1. Which statement best describes how atoms are different from molecules? a. atoms are the smallest unit of an element b. molecules are the smallest unit of an element c. atoms can be divided, molecules can’t 2. Which of the following materials is composed of only one kind of atom? A. Helium B. A compound C. An electron D. A molecule

The picture above shows two hydrogen atoms chemically bonded to one oxygen atom. The following picture is an example of A. an atom B. an element C. a molecule D. a subatomic particle

According to the model which is the chemical formula formaldehyde? A. H 2 C 2 O B. CH 2 O C. HCO D. C 2 HO

Which of the following pictures represents only one kind of atom? A C B D

Which of the following molecules could represent benzene (CH)? A B C

Which of the following materials is made of only one kind of atom? a. He c. C 6 H 12 O 6 b. H 2 O d. Na. Cl Two or more atoms joined in a definite ratio make a a. molecule b. electron c. atom d. proton

b. Describe the difference between pure substances (elements and compounds) and mixtures. Matter Pure Substances Elements Compounds Mixtures

Pure Substance—substance in which there is only one type of particle • Ex. Elements and Compounds Element—pure substance that cannot be separated into simpler substances by physical or chemical means Compound—a pure substance composed of two or more different elements that are chemically combined

Mixture—a combination of two or more substances that are not chemically combined ex. air, salt water, salad, brass, milk Each substance in a mixture has the same chemical makeup it had before the mixture formed

Mini Review Which of the following can be separated into several elements? a. nitrogen b. zinc c. air d. aluminum Which of the following is an example of the formation of a mixture? a. Tarnish forming on silver b. Kool-aid dissolving in water c. Alka seltzer reacting with water d. Hydrogen & oxygen reacting to produce water

Salt is composed of sodium and chlorine chemically combined. Salt is an example of which of the following? a. an atom b. a compound c. an electron d. a mixture Which of these substances is an element? a. steel b. chlorine c. plastic d. sugar Which formula represents a compound? a. Si. O 2 b. N 2 c. Ag d. Au

What is the main difference between compounds and mixtures? a. Mixtures combined chemically while compounds are combined physically b. Mixtures are combined physically while compounds are combined chemically Which of the following formulas represents a compound? A. He B. N 2 C. H 2 O D. O 2

Which of the following is an example of a container that is filled with a pure substance rather than with a mixture? a. A tire filled with air b. A jar filled with salt water c. A balloon filled with helium d. A glass filled with chocolate milk Which of the following molecules represents the molecule NH 3?

An example of a mixture is a. Salt (Na. Cl) c. Brass b. Neon (Ne) d. Water (H 2 O) Sterling silver is a combination of silver and copper. Which of the following is also a combination of two or more metals? A aluminum B lead C gold D brass

Which of the following pieces of equipment should be used to separate this mixture? A magnet B balance C funnel D hot plate

Which picture below represents a mixture? A B C D

c. Describe the movement of particles in solids, liquids, gases, and plasmas states. Solids • Have definite shape and volume • Particles are very close together (strong attraction) • Particles vibrate in place

Liquids • Have definite volume • Takes the shape of its container • Particles move more than in a solid but less than in a gas Gas • No definite shape or volume • Particles move quickly • Lots of space between particles

Plasma—gas that contains electrically charged particles Where can we find plasma? • Stars • Nebulas • Auroras (Northern Lights) • Certain TVs • Lightening

Add energy Solid Liquid Take away energy Gas Take away energy Liquid Gas

Mini Review Bromine can vaporize if heated. This means that with enough heat, bromine can a. Be destroyed b. Change from a liquid to a solid c. Be changed into a gas d. Become water vapor A material has a definite volume but a changing shape. What is it? a. A liquid b. a gas c. A solid d. water

Particles would be closest together in which substance? A. Kool-Aid B. A nail C. Air D. Water

In which form of water will the particles in a sample move slowest? a. Ice b. liquid water c. water vapor d. steam What happens to the particles of a solid as they are exposed to warm temperatures? a. The particles decrease in speed b. The particles increase in speed c. The particles become more rigid d. The motion of the particles is unchanged

Which of the following statements is true of all different types of matter? a. The particles move extremely fast and far apart b. The particles vibrate in place c. The particles move at the same speed. d. The particles are always in motion.

Which substance has a definite shape and definite volume? a. a crystal of table salt b. a solution of saltwater c. water vapor d. iced tea The melting point for water is 0 degrees Celsius. The boiling point of water is 100 degrees Celsius. At what temperature would water start to condense? a. 0 b. 100

What state of matter exists between numbers 3 and 4? A. B. C. D. Solid Liquid Gas Plasma

At which point will the particles of water have the LEAST movement? A. Point A C. Point C B. Point B D. Point D A B 0 o C D 100 o

A scientist uses an instrument to observe the pattern of molecules in a substance. The picture below shows what the scientist sees. What state of matter is the scientist most likely observing? A gas B liquid C vapor D solid

Which describes a change from gas to liquid? a. Boiling b. condensing c. Freezing d. sublimation What happens to particles when a solid changes to a liquid? a. They speed up b. They slow down c. Speed doesn’t change d. They stop moving

When water evaporates it a. Is a physical change b. Is a chemical change c. Is permanently a gas d. Can not be changed into water again Which state of matter has the least energy? A. Solid B. Liquid C. Gas D. Plasma

What happens to particle movement as a gas becomes a liquid? a. The particles speed up b. The particles slow down c. The particles stop moving d. The speed of the particles stays the same

d. Distinguish between physical and chemical properties of matter as physical (i. e. , density, melting point, boiling point) or chemical (i. e. , reactivity, combustibility). Physical Property—can be observed or measured without changing the matter’s identity

Common Physical Properties: v Magnetism v Odor v Conductivity v Density=m/v v Strength v State v Flexibility v Ductility v Volume v Malleability v Color v Solubility v Boiling Point v Melting Point x L = V H x W D= m/v

Chemical Property • Matter’s ability to change into a new substance that has different properties and a new chemical composition • Observed when a chemical change takes place

Chemical Properties: Flammability—Flashpoint less than 37. 8 degrees Celsius Combustibility—flashpoint greater than 37. 8 degrees Celsius (the difference between flammability and combustibility is how easily they ignite—aka their flashpoints) Reactivity—the ability of an atom or molecule to combine with another atom or molecule

Mini Review Which statement describes a chemical property of matter? a. The density of ice is 0. 4 g/m. L b. The boiling point of ethanol is 78. 4◦C c. Sodium is a very reactive element d. Rust is a flaky material with an orange-red color

A chemical property of aluminum is… A. Aluminum is silver B. The density is 10. 49 g/cm 3 C. The melting point is 962◦C D. Aluminum does not react with water

Mercury melts at -38. 87◦C and boils at 356. 58◦C. What is the freezing point of mercury? a. -38. 87 ◦C b. 0 ◦C c. 100 ◦C d. 356. 58 ◦C What is the volume of a box that is 5 cm by 2 cm by 3 cm? a. 30 cm b. 30 cm 3 c. 10 cm d. 10 cm 3

Which action will result in a product with new chemical properties? A shredding newspaper B boiling water C cutting wood D burning toast Which of the following represents a chemical reaction? A a sugar cube dissolving in water B ice cubes forming in a freezer C ice cream melting in a bowl D a cake baking in an oven

What is the density of an object that has a mass of 25 grams and a volume of 5 cm 3? a. 30 g/cm 3 b. 125 g/cm 3 c. 5 g/cm 3 d. 20 g/cm 3 Objects float because… a. They are more dense than water b. They are less dense than water c. They have more buoyant force than the water d. Everything floats

A student added a small ball to a graduated cylinder containing 10 milliliters of water. What is the volume of the ball? A 5 m. L B 10 m. L C 15 m. L D 20 m. L

A student divides several cubes into two groups, based on whether or not each cube can float in water. What property is the student using to classify the cubes? A weight B density C conductivity D mass Which physical property of matter describes the ability of a substance to transfer heat and electricity? a. Solubility b. Conductivity c. Malleability d. Density

Using the density column and the data table shown, which of the samples will probably float on top of the oil? A. Sample C B. Sample B C. Sample A D. Sample D

Which physical property of matter describes a substance’s ability to dissolve in another substance? a. Density b. ductility c. Malleability d. solubility Which physical property of matter describes metal’s ability to be pounded and shaped? a. Density c. Ductility b. Malleability d. Solubility

Which of the following describes a chemical property of matter a. Sodium is highly reactive with water b. An ice cube melts when placed in the sun c. Water boils at 100◦C d. The density of water is 1 g/m. L What two quantities must be known to calculate the density of a sample of matter? A. Color and mass B. Mass and volume C. Length and mass D. Solubility and mass

Identify the following properties as physical or chemical properties Magnetism Reactivity Density Boiling Point Size Texture Malleability Freezing point Combustibility Ductility Odor Volume Flammability Solubility

e. Distinguish between changes in matter as physical (i. e. , physical change) or chemical (development of a gas, formation of precipitate, and change in color). Physical Changes • A change that affects one or more physical properties of a substance • Does Not form new substances

Examples • • • bending (nail) crushing (can) cutting (paper) dissolving (sugar) freezing (ice) • • • melting (butter) molding (clay) pounding (metal) mixing (kool-aid) sanding (wood)

Chemical Changes • The process by which one or more substances actually change into entirely new substances with different properties • Involve chemical reactions • Hard to reverse

Evidence of changes A new substance is formed Change in odor (sour milk) Change in color (jewelry, copper dome) Production of heat (exothermic) (hand warmer) Absorption of heat (endothermic) (cool pack) Fizzing, foaming, bubbles (release of gas) (effervescent tablets) • Release of sound or light (fireworks) • Forms a precipitate (a solid from solutions) • • •

Examples of Chemical Changes: • Leaves changing color in fall • Alka-Seltzer Tablet in water • A candle burning • A cake/bread baking • Toasting bread • Digesting food • Metal rusting • Silver tarnishing • Copper tarnishing (Statue of Liberty) • A battery working • Roasting marshmallows • Frying an egg

Mini Review Which is an example of a chemical change? a. Ice melting b. lava cooling c. Wood being chopped d. iron rusting Why would dissolving salt in water be considered a physical change? a. The salt disappears forever. b. A new substance is produced. c. The salt changes its state. d. The salt keeps its identity.

During physical changes, matter always retains its a. size. c. state. b. identity. d. texture. Which of the following is a characteristic of ALL chemical changes? A. A different state of matter is produced B. Some mass is converted to energy C. Some form of light is given off D. A new material is formed

A student mixes two clear liquids in a flask. A moment later a white solid forms at the bottom of the flask. What can the student conclude? a. A physical change occurred b. A chemical change occurred c. No new substances have formed d. A mixture has been created

Which of the following statements best supports the idea that a chemical reaction is occurring when baking soda is combined with vinegar? A. The baking soda disappears B. Gas is produced. C. Two different substances are combined. D. The substances no longer look the same.

All of the following are signs of a chemical reaction except A. color change B. development of a gas C. formation of precipitate D. change in state When making cookies, which process involves a chemical change? A. Mixing the sugar and the flour B. Rolling out the dough C. Cutting the dough with cookie cutters D. Baking the dough

Let’s Practice—Decide whether each change is physical or chemical Melting chocolate Baking a cake Burning a match Adding kool-aid mix to water Crushing a pill Evaporating water Digesting food Making Jello Burning gas in a car

Using a cookie cutter to cut cookie dough Baking cookies The Statue of Liberty oxidizing Molding play-dough Leaves changing color in the fall Metal rusting Silver tarnishing Turning water into ice Cracking an egg A battery working Frying an egg

f. Recognize that there are more than 100 elements and some have similar properties as shown on the Periodic Table of Elements. • Elements in a family or group have similar properties • They have similar properties because they have the same number of electrons in their outer energy level

A Column of elements is called a group or family A row of elements is called a period (think: a period goes at the end of a sentence)

Elements are classified as metals, nonmetals, and metalloids Metals • Most elements are metals • Are found to the left of the zigzag line • Most are solid at room temperature • Most are shiny and good conductors • Malleable—can be flattened • Ductile—can be drawn into wires

Nonmetals • Right of the zigzag line on the periodic table • Elements in group 18 (Noble Gases) have a complete set of electrons in their outer level • More than ½ are gases at room temperature • Many nonmetal properties are the opposite of properties of metal Metalloids • Also called semiconductors • Border the zigzag line on the periodic table • Have some properties of metal and some of nonmetals

Mini Review What do the elements sulfur (S), nitrogen (N), phosphorus (P), and bromine (Br) have in common? A They are noble (inert) gases B They are nonmetals C They have the same thermal conductivity D They have the same number of protons

The elements highlighted in the picture above are members of which group? A. Alkali metals B. Alkaline Earth metals C. The Halogens D. The Noble Gases The elements in this group are A. Highly reactive B. Somewhat reactive C. Non reactive

In which region of the table would nonmetals be found? A 1 B 2 C 3 D 4 Each element on the periodic table has its own unique type of A. atom B. molecule C. compound D. electron

The columns highlighted on the periodic table above are called A. Periods B. Groups or Families C. Transition Columns D. Periodic Columns What forms when atoms bond? A. molecules and compounds B. Electrons and protons C. groups or families D. periods or rows

Which class of elements best conducts electricity? A metals B nonmetals C metalloids Which element is represented in the 6 C square above? 12. 0 A. Calcium B. Carbon C. Chlorine D. Cesium What does the number 6 represent? A. the element’s atomic number B. the element’s atomic mass C. the number of neutrons D. the number of protons and neutrons

Which of the following atoms would be most likely to form chemical bonds?

The element fluorine (F) is a very reactive non metal with 7 valence electrons. Which other element shares these properties? A. oxygen (O) B. sulfur (S) C. silver (Ag) D. iodine (I) What can group/family numbers on the periodic table help you determine? a. the number of valence electrons b. the number of protons c. the number of electrons d. the number of neutrons

Which of the elements is most metallic? A. Titanium (Ti) B. Germanium (Ge) C. Bromine (Br)

Which area includes an element that is a gas at room temperature? A. Area 1 B. Area 2 C. Area 3

g. Identify and demonstrate the Law of Conservation of Matter. Law of Conservation of Mass/Matter— states that mass is neither created nor destroyed in ordinary chemical and physical changes

• Atoms are not lost or gained in a chemical reaction—just rearranged • The mass of the reactants will equal the mass of the products • A chemical equation must show the same numbers and kinds of atoms on both sides of the arrow (it must be balanced)

Mini Review The chemical formula for water is always H 2 O. What is the ratio of hydrogen to oxygen in a molecule of water? a. 1: 1 b. 1: 2 c. 2: 1 d. 2: 2 Which is the product in this chemical formula? N + O 2 → NO 2 a. N, O 2 b. O 2 c. O d. NO 2

How many atoms of oxygen must have been present in the reactant of the equation below? a. 1 ? CO 2 b. 2 c. 3 d. 4

In the equation below, how many atoms of hydrogen are present in the reactants? a. 1 b. 2 c. 3 d. 4 How many atoms of oxygen are in the reactants? a. 1 b. 2 c. 3 d. 4

What should the mass be after the reaction takes place? a. 299. 23 g b. 300. 23 g c. 325. 23 g d. 400. 23 g

What does the Law of Conservation of Matter state? A. The total mass of the reactants is greater than the total mass of the products B. The total mass of the reactants is less than the total mass of the products C. The total mass of the reactants equals the total mass of the products D. Matter cannot change form

10/3/11 Cu + CO 2 Cu. CO 2 40 g ? 100 g What must be the missing mass? a. 40 g b. 50 g c. 60 g d. 100 g

Tina combined 25 grams of vinegar and 25 grams of baking soda in a sealed plastic bag and watch a chemical reaction take place. What should the mass be after the reaction? A. 50 grams B. 75 grams C. 100 grams D. 125 grams