SCIENCE 8 CHEMISTRY UNIT TEST REVIEW PACKAGE ANSWER KEY

Transcription

1 SCIENCE 8 CHEMISTRY UNIT TEST REVIEW PACKAGE ANSWER KEY This package is only a START. Once you have gone through this package, then you should review your notes IN DETAIL, using this package as a guide for the kinds of questions to prepare for, and as a focus for those sections you need to spend more time on. 1. UNDERSTANDING MATTER. Write the meaning of each of the following words, and give an example that clearly demonstrates each: MATTER: MASS: VOLUME: SHAPE: FLOW: DEFINITION Anything that has a mass and a volume The amount of matter in an object The amount of space that matter takes up The form that matter takes Supporting example An ice cube, a glass of juice, and oxygen gas A candle s mass is determined to be 18.4grams 12.6 ml of water is poured into a graduated cylinder The water in the pail froze into a cylindrical shape The movement of matter The hot steam from the pot of boiling water flowed up onto the ceiling

2 2. PROPERTIES OF THE STATES OF MATTER. Describe (in detail), each of the following properties for the states of matter: Volume Shape Flow SOLID Has a fixed volume Has a fixed shape Can NOT flow LIQUID Has a fixed volume Takes the shape of the container CAN flow GAS Takes the volume of the container (will expand or contract to fill the container) Takes the shape of the container CAN flow

3 3. CHANGES OF STATE. Name each of the changes of state, according to which phases are involved. State whether heat (energy) is added or given off in each case. Change of state Starting Phase Ending Phase Is Heat ADDED or RELEASED VAPOURIZATION (If happening slowly: evaporation) (If happening very quickly: BOILING) Liquid to Gas HEAT IS ADDED SUBLIMATION Solid to Gas HEAT IS ADDED SOLIDIFICATION (or freezing) Liquid to Solid HEAT IS RELEASED (or REMOVED) DEPOSITION Gas to Solid HEAT IS RELEASED (or REMOVED) CONDENSATION Gas to Liquid HEAT IS RELEASED (or REMOVED) MELTING Solid to Liquid HEAT IS ADDED

4 4. THE KINETIC MOLECULAR THEORY. The Kinetic Molecular theory describes how the PARTICLES of MATTER move when HEAT or other type of ENERGY is added. A THEORY explains our OBSERVATIONS. So the Kinetic Molecular Theory explains our OBSERVATIONS about the MOVING particles of MATTER. The Particle Model of Matter and Kinetic Molecular theory state that all matter is made up of tiny PARTICLES. These particles are in constant MOTION. This motion is called KINETIC energy. There are SPACES between the particles of matter. These particles, and the spaces between them, are too SMALL to be seen. When ENERGY (usually HEAT) is added to particles, their KINETIC energy (the energy of motion) INCREASES.

5 THE KINETIC MOLECULAR THEORY continued Using the given images, state the Phase (or State) that is being represented and elaborate on the spaces, energy, and movement of the particles. STATE represented in the given image SPACES between particles ENERGY of particles MOVEMENT of particles GAS Large spaces Between particles HIGH ENERGY VERY FAST 0 gas particles are zooming around LIQUID Some spaces Between particles MEDIUM ENERGY SOMEWHAT FAST liquid particles can flow past each other SOLID Barely any spaces Between particles LOW ENERGY NOT VERY FAST (just vibrating slightly)

6 5. TEMPERATURE, THERMAL ENERGY, and HEAT. TEMPERATURE describes the SPEED (average kinetic energy) of the particles in an object. An object s TEMPERATURE does not change if you have more of that object. If particles are moving fast, they have a HIGH temperature. If particles are moving slow, they have a LOW temperature. To speed up particles, you should add HEAT or ENERGY. The term that depends on the size of the object is HEAT. HEAT is defined as the TOTAL ENERGY of the object. If you have MORE of the object, then we say that it has more HEAT. Anders Celsius developed a scale to measure temperature. Describe how he did this: He filled a tube with liquid mercury. He put this tube of mercury into ICE water and noted the measure of the liquid mercury as it condensed down near the bottom of the tube. He marked this spot 0 0 C. He then put this tube of mercury into BOILING water and noted the measure of the liquid mercury as it expanded up near the top of the tube. He marked this C.

7 How does Anders Celsius experiment to determine the freezing point and boiling point of water, relate to the Kinetic Molecular Theory? Be VERY SPECIFIC in your answer, being sure to elaborate on the spaces between particles, the energy of the particles, and the movement of particles. The ICEY cold water caused the mercury particles in the tube to slow down and get closer together. As a result the spaces between the particles got smaller and the mercury particles started to move slower and take up less space in the tube. They shrank down and only filled up the bottom space of the tube. This was noted as a zero value. The BOILING hot water caused the mercury particles in the tube to speed up and get farther apart. As a result the spaces between the particles got bigger and the mercury particles started to move faster and take up more space in the tube. They expanded up and filled up almost all the space in the tube. This was noted as a hundred value. Explain the significance of the KELVIN scale for temperature: Lord Kelvin wanted a temperature scale that never had to use negative numbers. So Kelvin said his lowest temperature would be O Kelvin. This corresponds to NEGATIVE 273 on the Celisus scale ( C). Having a temperature scale without negative numbers is really useful in Chemistry and Physics. Give a very clear example of each: Something that has HIGH heat But a medium to low temperature A large bathtub filled to the very top with water at 37 0 C (body temperature) Something that has LOW heat But a HIGH temperature A small cup of espresso or tea at 98 0 C

8 6. ATOMIC THEORY MODELS AND TIMELINE. Fill in the following table for each of the scientists involved in the development of Atomic Theory: Democritus 465 BC John Dalton 1803 Dmitri Mendeleev 1869 JJ Thomson 1897 Ernest Rutherford 1911 Niels Bohr 1915 Werner Heisenberg 1925 James Chadwick 1932 Hypothesized that atoms cannot be destroyed, are always moving, and are indivisible Created the first real atomic theory Hypothesized that the atom was a tiny hard sphere Believed that atoms of a given element are identical Suggested future elements would be discovered and fitted into the periodic table Proposed the basis of our modern periodic table Discovered the electron Used the cathode ray tube in his discovery Created the plum pudding model of the atom Discovered that the atom is mostly empty space Discovered that the proton had a positive charge Did the gold foil experiment Created a model of the atom with electrons moving around the nucleus in fixed orbits Uncertainty principle: A particle s position, energy, and time can never be precisely known Worked with the Quantum Theory of the Atomic Model Discovered the neutron Found the missing mass of the atom s nucleus

9 CHOOSE ONE of scientists above, describe IN DETAIL HOW the scientist developed this contribution to the atomic theory (how the experiment was conducted). And what RELEVANCE or IMPORTANCE this discovery had of the Model of the Atom. Use the research you did for your Atomic Theory Timeline Project. 7. ELEMENTARY and SUBATOMIC PARTICLES. The three main subatomic particles that Chemists talk about are: PROTONS NEUTRONS ELECTRONS These subatomic particles are made up of ELEMENTARY particles, which are the building blocks of the Universe. Fermions are a type of Elementary Particles. All matter is made up of FERMIONS. Two types of Fermions are QUARKS and LEPTONS Quarks are the building blocks of PROTONS and NEUTRONS There are SIX types of quarks and each type is called a FLAVOUR The characteristics of each quark are referred to as COLOUR. Particles made up of quarks are called HADRONS Leptons are the building blocks of ATOMS. A common example of LEPTONS is ELECTRONS. Bosons are the FORCE-carrying particles. They are made up of TINY BUNDLES OF ENERGY Light is made up of a type of boson called a PHOTON Another type of Boson, the GLUON acts as the force-carrier between quarks in creating one of the fundamental forces of nature, the STRONG force.

10 8. THE FOUR FUNDAMENTAL FORCES. Write each of the following statements under the appropriate heading in the table. STRONG FORCE WEAK FORCE ELECTROMAGNETIC FORCE The strongest of the forces Holds the nucleus of an atom together Uses gluons to hold protons and neutrons together The second strongest force (only weak when compared to the strong force) Responsible for radioactivity in some elements Electricity and magnetism are interconnected Static electricity, like a balloon sticking to a wall, or magnetism, like magnets attracting or repelling each other are both the result of a single force Positively charged protons attract negatively charged electrons Holds the atom together GRAVITY The weakest of the fundamental forces Holds you to the Earth, and the Earth to the sun (etc.) Very easy to overpower

11 9. HOW ELEMENTS ARE NAMED. List one example for each category: Element that was discovered prehistorically Element named after a place on earth Element named after a god (mythology) Element named after a person (Scientist) Man made element named after the Scientist who discovered it Element named for a property or characteristic Element named for a planet or celestial object Name of the Element Symbol (short form) for the element You must choose the elements you want to memorize / learn for each category. Be sure that you can spell it correctly and write it s short form symbol correctly. It matters when you use a capital letter and when you use a lowercase letter.

12 10. PHYSICAL AND CHEMICAL PROPERTIES. Define Physical Property and give one example: A characteristic of matter that can be observed without changing the matter into a new substance. Can often be determined by just seeing, smelling or touching the substance. Eg. Odour, Viscosity. Define Chemical Property and give one example: A characteristic of matter that can be observed when the matter chemical combines with other matter or is changed due to energy input or output. Often observed when matter changes into a new substance (but not necessarily) Eg. Flammability, ozidizing ability, corrosiveness Write P for Physical Property and C for Chemical Property & explain WHY P or C Explanation Colour of matter P Can just be observed by looking at it Combustibility of a chemical Melting Point of a solid ph of a liquid or solution The ability of a metal to corrode or rust C P C C Chemical must be exposed to source of flame to ignite it This is a reversible property and the substance does not change its chemical identity when it melts This property is exhibited when an acid loses an H to turn the opposite, base version of the molecule (or vice versa) Corrosion or rusting occurs when oxygen combines with a metal to form a new oxide compound. Density of matter P This is a property that can be measured without changing the substance s chemical identity

13 11. ATOMS, ELEMENTS, MOLECULES, and COMPOUNDS. Give an example of: An ATOM that can also be used as an example of an ELEMENT Cu or O An ELEMENT that can NOT be used as an example of an ATOM O 2 or P 4 An ELEMENT that can also be used as an example of a MOLECULE O 2 or P 4 An ELEMENT that can NOT be used as an example of a MOLECULE Cu or O A MOLECULE that can NOT be used as an example of an ELEMENT H 2 O or CH 4 A MOLECULE that can also be used as an example of a COMPOUND H 2 O or CH 4 An MOLECULE that can NOT be used as an example of a COMPOUND O 2 or P 4 A COMPOUND that can NOT be used as an example of a MOLECULE all compounds can also be called molecules (although in Chem 11 we would suggest that the type of BONDING in the Chemical Formula suggest whether we should be calling it a compound or a molecule)

14 12. PHYSICAL AND CHEMICAL CHANGES. Define Physical Change and give one example: A change where no new matter is formed. Characterized by REVERSIBILITY. Eg. Dissolving salt in water (it can be removed by precipitation or crystallization Also any change of state. Define Chemical Change and give one example: A change where new matter IS formed. Characterized by a lack of REVERSIBILITY. Eg. An explosion, Something burning or cooking, An acid neutralizing a base Write P for Physical Change and C for Chemical Change and explain WHY P or C Explanation An ice cube melts P It can be reversed by cooling it back down A solid crystal dissolves in P It can be reversed by recrystallizing the water and changes colour dissolved solid A green solid is heated C Assuming that cooling it down does not and turns black change it back, the assumption leads us to believe a new chemical substance Baking soda is added to vinegar and bubbles form ELEPHANT toothpaste (H 2 O 2 is degraded to O 2 and H 2 O) Dry ice is created in very cold conditions (CO 2 gas turns into CO 2 solid) C C P was formed. The bubbles are carbon dioxide gas which were not one of the two original substances mixed together This is a non reversible chemical reaction where new substances are formed and a lot of energy is given off This is a reversible change of state

15 PHYSICAL AND CHEMICAL CHANGES continued Use your responses to this lab report in your studying. Be sure that you are THOROUGHLY explaining, using all of the concepts we have talked about in the Science 8 Chemistry unit, including: Kinetic Molecular Theory, Temperature and Heat (energy), Atoms, Elements, Molecules, and Compounds, and Physical and Chemical Properties. Explain what part of the Candle lab was a PHYSICAL CHANGE. Explain WHY by explaining what the molecules are doing as the Candle is burning. How could you PROVE that it is a PHYSICAL CHANGE? Explain what part of the Candle lab was a CHEMICAL CHANGE. Explain WHY by explaining what the molecules are doing as the Candle is burning. How could you PROVE that it is a CHEMICAL CHANGE? What kind of change is occurring when a BUNSEN BURNER is attached to the gas tap and is lit with the sparker? Explain WHY by explaining what the molecules are doing as the Bunsen Burner is burning.

16 PHYSICAL AND CHEMICAL CHANGES continued Think about our Bunsen Burner lab as you answer these questions. Be sure that you are THOROUGHLY explaining, using all of the concepts we have talked about in the Science 8 Chemistry unit, including: Kinetic Molecular Theory, Temperature and Heat (energy), Atoms, Elements, Molecules, and Compounds, and Physical and Chemical Properties. A test tube containing Copper Carbonate is heated over the Bunsen Burner. The substance turns from a green powder to coarse black granules when heated. The mass decreases as CO2 gas escapes while the chemical is heated. Explain if this was a PHYSICAL or CHEMICAL CHANGE. Explain WHY by explaining what the molecules are doing as the change is occurring. A test tube containing a bluish-green crystalline solid called Copper Sulphate pentahydrate is heated over the Bunsen Burner. The substance turns from a bluish-green powder to dark green when heated. The mass decreases as the chemical is heated. Once the substance is cooled down enough to handle, a student then adds 4 drops of water to the test tube and the substance changes back to it s original colour. Explain if this was a PHYSICAL or CHEMICAL CHANGE. Explain WHY by explaining what the molecules are doing as the change is occurring.