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Introduction to Chemistry Workbook Units 12 1 REGENTS CHEMISTRY
Introduction to Chemistry Workbook Units 1-‐2
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REGENTS CHEMISTRY
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Key Ideas • Matter is classified as a pure substance or as a mixture of substances. (3.1q) • The three phases of matter (solids, liquids, and gases) have different properties. (3.1kk) • A pure substance (element or compound) has a constant composition and constant properties throughout a
given sample, and from sample to sample. (3.1r) • Elements cannot be broken down by chemical change. (3.1u) • Mixtures are composed of two or more different substances that can be separated by physical means. When
different substances are mixed together, a homogeneous or heterogeneous mixture is formed. (3.1s) • The proportions of components in a mixture can be varied. Each component in a mixture retains its original
properties. (3.1t) • Differences in properties such as density, particle size, molecular polarity, boiling point and freezing point, and
solubility permit physical separation of the components of the mixture. (3.1nn) • A solution is a homogeneous mixture of a solute dissolved in a solvent. The solubility of a solute in a given
amount of solvent is dependent on the temperature, the pressure, and the chemical natures of the solute and solvent. (3.1oo)
• Energy can exist in different forms, such as chemical, electrical, electromagnetic, thermal, mechanical, and nuclear. (4.1a)
• Heat is a transfer of energy (usually thermal energy) from a body of higher temperature to a body of lower temperature. Thermal energy is the energy associated with the random motion of atoms and molecules. (4.2a)
• Temperature is a measurement of the average kinetic energy of the particles in a sample of material. Temperature is not a form of energy. (4.2b)
• The concepts of kinetic and potential energy can be used to explain physical processes that include: fusion (melting), solidification (freezing), vaporization (boiling, evaporation), condensation, sublimation, and deposition. (4.2c)
• A physical change results in the rearrangement of existing particles in a substance. A chemical change results in the formation of different substances with changed properties. (3.2a)
• Chemical and physical changes can be exothermic or endothermic. (4.1b) • The structure and arrangement of particles and their interactions determine the physical state of a substance at
a given temperature and pressure. (3.1jj)
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VOCABULARY
For each word, provide a short but specific definition from YOUR OWN BRAIN! No boring textbook definitions. Write something to help you remember the word. Explain the word as if you were explaining it to an elementary school student. Give an example if you can. Don’t use the words given in your definition!
Significant Figures: __________________________________________________________________________________
Matter: ___________________________________________________________________________________________
Substance: _________________________________________________________________________________________
Element: __________________________________________________________________________________________
Compound: ________________________________________________________________________________________
Mixture: ___________________________________________________________________________________________
Homogeneous Mixture: ______________________________________________________________________________
Heterogeneous Mixture: ______________________________________________________________________________
Solution: __________________________________________________________________________________________
Decant: ___________________________________________________________________________________________
Filter: _____________________________________________________________________________________________
Distillation: ________________________________________________________________________________________
Chromatography: ___________________________________________________________________________________
Solid: _____________________________________________________________________________________________
Liquid: ____________________________________________________________________________________________
Gas: ______________________________________________________________________________________________
Evaporation: _______________________________________________________________________________________
Condensation: ______________________________________________________________________________________
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Melting: ___________________________________________________________________________________________
Freezing: __________________________________________________________________________________________
Sublimation: _______________________________________________________________________________________
Deposition: ________________________________________________________________________________________
Kinetic Energy: _____________________________________________________________________________________
Potential Energy: ____________________________________________________________________________________
Physical Change: ____________________________________________________________________________________
Chemical Change: ___________________________________________________________________________________ Section 1 Metrics
Use Reference Tables C and D to help you answer the following questions about the metric system.
1. Give the unit used to describe the following:
a. Mass _______ d. Time: ______
b. Volume _______ e. Temperature: ______
c. Energy _______ f. Pressure: ______
2. Complete the following number line by adding the prefixes that pertain to the marked values:
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3. If a substance weighs 2.00 grams and you need the mass in kilograms, will the number appear to become smaller or larger? Explain your answer.
4. If a liquid has a volume of 5800 mL and you need the volume in Liters, will the number appear to become smaller or larger? Explain your answer.
5. If a substance has a mass of 0.00235 grams and you need the mass in milligrams, will the number appear to become smaller or larger? Explain your answer.
6. Convert the following:
a. 900 km = __________ m h. 568 mm = __________ m b. 200 kg = __________ g i. 52 mg = __________ g c. 5.00 m = __________ km j. 0.025 J = __________ mJ d. 7000 J = __________ kJ k. 0.859 s = __________ ms e. 800 cm = __________ m l. 0.0256 m = __________ um f. 20 cg = __________ g m. 0.000589g = __________ ng g. 2.0 L = __________ cL n. 0.00005987 m = __________ pm
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Section 2 Scientific Notation
Scientific notation is used to express numbers that are very large or small. An example is 6.02x1023 which is a large number called a “mole” in chemistry. It means 6.02 times 10 twenty three times; or 602000000000000000000000! The number 6.02 is the “base number”, which must be between 1 and 10. The number 23 is the “exponent” which represents the number of place the decimal moved to get the base number between 1 and 10.
Another number, 5.12x10-‐5 is a small number. The exponent is negative which really means the 5.12 is divided by 10 five times. So the rule is if the exponent is positive the real number is large and if the exponent is negative the real number is small.
Convert the following numbers into scientific notation:
1) 3,400 ____________________________ 2) 0.000023 ____________________________ 3) 101,000 _______________________________ 4) 0.010 _______________________________ 5) 45.01 _______________________________
6) 1,000,000 ____________________________ 7) 0.00671 ____________________________ 8) 4.50 _______________________________ 9) 560000 _______________________________ 10) 0.0000098 ____________________________
Convert the following numbers into standard notation: 1) 2.30 x 104_______________________________ 2) 1.76 x 10-‐3_______________________________ 3) 1.901 x 10-‐7_____________________________ 4) 8.65 x 10-‐1_______________________________ 5) 9.11 x 103_______________________________
6) 5.40 x 101_______________________________ 7) 1.76 x 100_______________________________ 8) 4.5x10-‐1 _______________________________ 9) 8.0x10-‐4 _______________________________ 10) 4.62x102_______________________________
Name:________________________
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Section 3 Significant Figures
1. A student finds the mass of a solid using 4 balances. Explain his findings in terms of precision and accuracy. Data Mass 1 45.698 grams Mass 2 45.7 grams Mass 3 45.69842 grams Mass 4 45.9 grams 2. A beaker has marks every 50mL. A cylinder has marks every 10mL. A pipette has marks every 1mL. Is the pipette the most accurate or precise tool? Explain your answer. 3. Sally measures 11mL of water in the beaker described in question 2. Henry measures 11mL in the pipette described in question 2. When they add their water together in one cup, do they have exactly 22mL combined? Why or why not? In order to report the most precise and accurate data possible we must learn to count significant figures. When measuring a substances mass, volume, etc. the device requires you to measure “one place beyond.” All the numbers you report count as a significant figure sig fig) except leading zeros and sometimes the trailing zeros. Let’s investigate:
Example 1: A piece of aluminum has a mass of 0.0521 grams which had 3 sig figs. This is not 5 sig figs because if we convert that mass to mg the mass becomes 52.1 mg. Again the number has 3 sig figs which shows it didn’t get any more precise. Proof that leading zeros never count.
Example 2: A beaker of water contains 520 mL which has 2 sig figs. The trailing zero doesn’t count this time because if we convert to liters the volume is .52 L. The trailing zero was not measured. If we want to show that it was exactly 520 mL we would report it as 520. mL with a decimal point. That way if we convert to liters it is .520L.
Example 3: A reaction takes 0.0025050 s which has 5 sig figs. Remember the first three zeros are place holders and don’t count. If we convert to ms we get 2.5050 ms, also with 5 sig figs. The trailing zero was measured or else the student wouldn’t have reported it. The rule is: Leading zeros never count, trapped zeros always count they are measured) and trailing zeros count if there is a decimal.
Name:________________________
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Using the rules above, count the number of significant figures in the following measurements: 4. 3.456 L _____ 7. 0.000206 m _____ 5. 2.300 g _____ 8. 0.025600 L _____ 6. 1.258092 m _____ 9. 0.520301 J _____ If a piece of glassware is very precise it may have a lot of sig figs, as many as 4. A less accurate piece of glassware such as a beaker will only have 1 sig fig. If both pieces of glassware are used to measure quantities in a lab we have to round our results to the least precise measurement. When working with measurements the quantity with the least decimal places is the least precise. For example, if the beaker measures 10mL and a cylinder measures 10.1mL the cylinder is more precise. If the two quantities are added together the new volume is 20mL. The decimal must be rounded to make our answer to one sig fig. Therefore the rule is: When adding or subtracting measurements, round your answer to the lowest number of decimal places given. Complete the following operations and report to the correct number of significant figures. 10. 10.2 + 21 ________ 14. 0.023 -‐ 0.0004 _______ 11. 31.3 + 54.45 ________ 15. 5.068 -‐ 0.1 _______ 12. 22.59 + 21 ________ 16. 45.6 -‐ 22.12 + 11 _______ 13. 0.023 + 20.1 ________ 17. 0.0123 +5.689 – 0.014 _______ When performing calculations with our data sometimes we have to multiply and divide our data. In this case, the most precise answer is the one with the most sig figs. Since we need to round to our least precise measurement, we should round to the least number of sig figs given. For example, if the mass of a substance is 10.0 grams (3 sig figs) and the volume is 2 mL 1 sig fig) the density is 5 g/mL also 1 sig fig). The rule is: When multiplying or dividing measurements, round your answer to the lowest number of significant figures given. Complete the following operations and report to the correct number of significant figures. 18. 5.87 * 2.1 ________ 22. 589 / 12 _______ 19. 4 * 78 ________ 23. 78.632 / 52.3 _______ 20. 0.0235 * 9 ________ 24. 1569 / 24 * 2 _______ 21. 0.014 * 0.01 ________ 25. ( 596 * 32 ) / 22 _______
Name:________________________
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If both types of operations are used, always follow the multiplication rules (least sig figs). Finally, in scientific notation, only the base number counts, not the exponent or the 10). Use PEMDAS! 26. (22.1-‐10.0) / 2 ________ 28. 6.23x10-‐3/2.15x10-‐4 _________ 27. 12.35 / (4.56-‐2.14) ________ 29. (2.1x102 – 1.4x101) * 2 _________ Section 4 Density
1. The density of silver (Ag) is 10.5 g/cm3. Find the mass of Ag that occupies 965 cm3 of space. 2. A 2.75 kg sample of a substance occupies a volume of 250.0 cm3. Find its density in g/cm3. 3. Under certain conditions, oxygen gas O2) has a density of 0.00134 g/mL. Find the volume occupied by 250.0 g of O2 under the same conditions. 4. Find the volume that 35.2 g of carbon tetrachloride (CCl4) will occupy if it has a density of 1.60 g/mL. 5. The density of ethanol is 0.789 g/mL at 20oC. Find the mass of a sample of ethanol that has a volume of 150.0 mL at this temperature. 6. 30.0 g of each of the following acids are needed. Find the volume of each that must be measured out in a graduated cylinder.
A. hydrochloric acid ( HCl), density = 1.164 g/mL
B. sulfuric acid (H2SO4), density = 1.834 g/mL
C. nitric acid (HNO3), density = 1.251 g/mL
Name:________________________
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7. A rectangular block of lead (Pb) measures 20.0 mm X 30.0 mm X 45.0 mm. If the density of Pb is 11.34 g/cm3, calculate the mass of the block. 8. A cube of gold Au) has a side length of 1.55 cm. If the sample is found to have a mass of 71.9 g, find the density of Au. Section 5 Temperature 1) Convert 83 °C to Kelvin 2) How many Celsius degrees separate the freezing and boiling points of water? _______
What are these two temperatures? ________ & _________ 3) What is the lowest possible temperature in °C? _________ 4) How many Kelvin separate the freezing and boiling points of water? ______
What are these two temperatures? ________ & ________ 5) What is the lowest possible temperature in Kelvin? __________ 6) Using the temperature conversion formula on Table T in your Reference Tables, convert the following temperatures to either Celsius or Kelvin.
383 K 80C 323K 10 C 10K
7) Using Table S in your reference table what temperature does Sulfur melt at?
Name:________________________
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Section 6 Classifying Compounds Fill in the blank with a vocabulary word to determine the key ideas:
• Matter is classified as a pure substance or as a _________________________ of substances.
• A pure _____________________________ (element or compound) has a constant composition and constant
properties throughout a given sample, and from sample to sample.
• _____________________ cannot be broken down by chemical change.
• Mixtures are composed of two or more different substances that can be separated by physical
means. When different substances are mixed together, a ______________________________ or
heterogeneous mixture is formed.
• The proportions of components in a __________________________ can be varied. Each component in a
mixture retains its original properties.
• Differences in properties such as density, particle size, molecular polarity, boiling point and
freezing point, and solubility permit physical separation of the components of the __________________.
• A ______________________________ is a homogeneous mixture of a solute dissolved in a solvent. The
solubility of a solute in a given amount of solvent is dependent on the temperature, the pressure,
and the chemical natures of the solute and solvent.
Name:________________________
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Matter
PURE SUBSTANCES (each piece looks the same – PURE!)
-‐each piece has exact same composition.
MIXTURES (each piece is different – not pure)
Can NOT be separated by physical means
CAN be separated by PHYSICAL means
ELEMENT (simplest form of matter)
Example: Na, Cl2
HETEROGENEOUS MIXTURE (not uniform throughout— a pattern)
Example: Italian dressing, concrete, soil, chocolate chip cookie
Hetero = opposite
HOMOGENEOUS MIXTURE (uniform throughout—distinct pattern)
Example: saltwater, iced tea
Homo = same
COMPOUND or MOLECULE
(2+ different elements chemically combined)
Example: NaCl (table salt), H2O (water)
Can NOT be separated by chemical means
Separated by chemical means, only
Same composition throughout
Different composition throughout
Particle Diagram Particle Diagram
Particle Diagram Particle Diagram
Name:________________________
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Name:________________________
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Label each as a substance or mixture. Then determine if they are elements, compounds, homogeneous mixtures or heterogeneous mixtures.
Peanut butter: __________________________________ __________________________________
Gold: __________________________________ __________________________________
Salt water: __________________________________ __________________________________
Corn starch: __________________________________ __________________________________
Magnesium Fluoride: __________________________________ __________________________________
Oxygen: __________________________________ __________________________________
Aqueous sodium hydroxide: ______________________________ __________________________________ Explain the best way to separate the following mixtures: Salt water: __________________________________________________________________________________ Wet sand: ___________________________________________________________________________________ Classify each of the following with the combination of terms listed below.
(1) pure substance – element (3) mixture – homogeneous (2) pure substance – compound (4) mixture – heterogeneous
1. HCl (aq) 2. sugar (C11H22O11) 3. KBr (s) 4. Soil
5. Cl2 (g) 6. water 7. CH2(OH)2 (aq) 8. Sodium
9. Hg (l) 10. iron oxide 11.NH3 (l) 12. salt water
13. Matter that is composed of two or more different elements chemically combined in a fixed proportion is classified as (1) a compound (2) an element (3) a mixture (4) a solution
14. A compound differs from an element in that a compound (1) is homogeneous (2) has a definite composition (3) has a definite melting point (4) can be decomposed by a chemical reaction
Name:________________________
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15. A compound differs from a mixture in that a compound always has a (1) homogeneous composition (2) maximum of two elements (3) minimum of three elements (4) heterogeneous composition
16. A heterogeneous material may be (1) an element (2) a compound (3) a pure substance (4) a mixture
17. Which statement is an identifying characteristic of a mixture? (1) a mixture can consist of a single element (2) a mixture can be separated by physical means (3) a mixture must have a definite composition by weight (4) a mixture must be homogeneous
18. Which must be a mixture of substances?
(1) solid (2) liquid (3) gas (4) solution
19. Which substance can be decomposed by chemical means? (1) aluminum (2) octane (3) silicon (4) xenon
20. Which substance can be decomposed by chemical means? (1) ammonia (2) oxygen (3) phosphorus (4) silicon
21. Which substance can not be broken down by a chemical reaction? (1) ammonia (2) argon (3) methane (4) water
22. Two substances, A and Z, are to be identified. Substance A can not be broken down by a chemical change. Substance Z can be broken down by a chemical change. What can be concluded about these substances?
(1) Both substances are elements. (2) Both substances are compounds. (3) Substance A is an element and substance Z is a compound. (4) Substance A is a compound and substance Z is an element.
23. Which terms are used to identify pure substances?
(1) an element and a mixture (2) an element and a compound (3) a solution and a mixture (4) a solution and a compound
Name:________________________
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24. Two different samples decompose when heated. Only one of the samples is soluble in water. Based on this information, these two samples are
(1) both the same element (2) two different elements (3) both the same compound (4) two different compounds
25. Tetrachloromethane, CCl4, is classified as a
(1) compound because the atoms of the elements are combined in a fixed proportion (2) compound because the atoms of the elements are combined in a proportion that varies (3) mixture because the atoms of the elements are combined in a fixed proportion (4) mixture because the atoms of the elements are combined in a proportion that varies
Section 7 Phases
Directions: Using the boxes provided below as your container, place six circular molecules in each container representing the given phase. Then on each line with the arrow label which phase change is occurring. Last fill in the chart below about phases using the words provided in the parenthesis. SOLID (s) LIQUID (l) GAS (g)
Name:________________________
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Solid Liquid Gas Shape
(Has a fixed shape or takes the shape of the container)
Volume (Has a fixed volume or takes
the volume of the container)
Density (high or low)
Particle arrangement (rigid or free)
Attraction (particles are highly attracted and close or weakly attracted and
spread out)
Fill in the blank with a vocabulary word to determine the key ideas:
• The three phases of matter (_________________, ___________________, and _____________________) have
different properties.
• Heat is a transfer of ________________________________________ (usually thermal energy) from a body of
higher temperature to a body of lower temperature. Thermal energy is the energy associated with
the random motion of atoms and molecules.
• Temperature is a measurement of the average ________________________________________ of the particles
in a sample of material. Temperature is not a form of energy.
• The concepts of kinetic and potential energy can be used to explain physical processes that
include: fusion (melting), solidification (_____________________________), vaporization (boiling,
_____________________________), condensation, sublimation, and deposition.
• Chemical and _____________________________ changes can be exothermic or endothermic.
• The structure and arrangement of particles and their interactions determine the physical state of a
substance at a given temperature and pressure.
Name:________________________
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Which phase of matter has definite shape and volume? ________________________________
Which phase of matter is easily compressible? ________________________________
What type of energy is defined as stored energy? ________________________________
What type of energy s directly related to the temperature of a sample? ________________________________ Draw representations of the following:
Label the following graph with phases on each line segment and identify the melting and boiling point.
On which line segments is kinetic energy increasing? __________________________________
On which line segments is kinetic energy increasing? __________________________________
What is happening to the kinetic energy on line segment BC? __________________________________
What is happening to the potential energy on line segment CD? __________________________________
Solid Liquid Gas An element subliming
Name:________________________
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Section 8 Physical and Chemical Changes Fill in the blank with a vocabulary word to determine the key ideas:
• A _______________________________________ results in the rearrangement of existing particles in a
substance. A ________________________________________ results in the formation of different substances
with changed properties.
Label the following as physical change (P) or chemical change (C): Melting ice _____ Burning wood _____ Cutting paper _____ Sublimation _____ Rusting nails _____ Reacting with acid _____ Digesting _____ Painting _____ Heating copper _____
Review: Unit 1 & 2 METRIC 1. Using tables on page one of your reference table you should be able to identify which unit is used to measure each quantity and you should be able to convert between units using the prefixes. Locate the prefix assigned to the measurement unit that you are starting with and then find the prefix that you want to convert to. Count the number difference between the factors and then move your decimal that many places. a. Identify the unit used for each quantity: (1) mass _________ (4) temperature __________ (2) volume _________ (5) length __________ (3) energy _________ (6) time __________ b. Convert the following: (1) 568 mL to L ___________________ (2) 0.00897 g to mg ___________________ (3) 45700 mm to km ___________________
Name:________________________
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2. Density is the measurement of mass divided by volume. A substance’s density can help identify it. For example, water’s density is 1.00g/mL. Substances float in water of they have low densities, and sink when their densities are greater than 1.00 g/mL. a. Calculate the density of 5.00 gram sample of an unknown substance, which has a volume of 5.15mL. b. Using table S, identify the unknown substance in question (a) above. __________________________ c. Calculate the mass of a substance with a density of 2.50 g/mL and a volume of 23.0mL. d. Calculate the volume of a metal rectangle with a height of 2.0cm, a length of 3.0cm, and a width of 1.0cm. e. If the metal in question (d) above is iron, calculate the mass. (Hint: density is on table S) SCIENTIFIC NOTATION 3. Scientific Notation is used to represent very small or very large numbers. Convert the following to scientific notation: a. 0.00000345 ____________________________ b. 1098000000 ____________________________ c. 0.000345 ____________________________ d. 0.000005677 ____________________________ SIGNIFICANT FIGURES 4. All whole numbers 1-‐9 count. Proceeding zeros never count, trapped zeros always count, and trailing zeros count IF THERES A DECIMAL before the zero. Count the number of significant figures: 5678 0.09809 0.00345 0.0712 0.0987 10000 10200 102.0986
Name:________________________
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5. When rounding, your answer can only be as precise as your least precise measurement. When adding or subtracting numbers, round your answer to the lowest decimal place given. When multiplying or dividing, round your answer to the least number of significant figures. Calculate and round to the correct number of significant figures: a. 4.567 + 1.2 = _____________ d. 67065/87.2 = ________________ b. 678.345-‐234.98 = ______________ e. (54.0-‐32.34)/1.202 = ________________ c. 45 x789 = _____________ f. 3.108*(98.70-‐8.20) = __________________ ELEMENTS, COMPOUNDS, AND MIXTURES 6. Matter is anything that has a mass and takes up space. An element is the simplest form of matter, which cannot be broken down any further. Elements are listed on Table S and the periodic table. Their symbols start with an uppercase letter. a. Which of the following is not matter? _____________________ Magnesium Calcium Carbonate Salt water Heat b. Which of the above is an element? _____________________ 7. Compounds are composed of two or more elements. They can only be decomposed chemically. Elements and compounds are also known as substances. a. Which of the choices in number six was a compound? ________________________ b. How can compound be broken down? __________________________________________________ c. Which of the choices in question six are substances? ______________________________________ 8. Mixtures are physical combinations of two or more substances (elements and/or compounds). Mixtures can be homogeneous (completely mixed, cannot see the parts) or heterogeneous (unevenly mixed, can see the parts). Mixtures can be separated by physical means. Label each as homogeneous or heterogeneous: Sand: ____________________ Brass: ______________________________ Milk: ____________________ Oil and water: ________________________
Name:________________________
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9. Compounds must be separated chemically but mixtures can be separated easily using physical methods. a. Match each method with its name. Distillation Separated by differences in particle size Filtration To pour off the top layer of an uneven mixture Decant Separated by differences in boiling point. Chromatography Just a test for purity b. Which of the above processes only work if the mixture is heterogeneous? _____________________ 10. Mixtures are composed of solutes that dissolve and solvents that do the dissolving. The solute should be the smaller quantity. a. In iced tea, what is the solute? ___________________ solvent? ________________________ b. In air, name a solute: _________________ c. Do all solvents have to be water? Explain. _______________________________________________ SOLIDS, LIQUIDS, AND GASES 11. A solid has a definite shape and volume. Solids are arranged in a geometric pattern. Liquids have a definite volume but take the shape of the container they are in. Gases have an indefinite shape and volume; they take the shape and volume of the container. Gases are easily compressed. a. Draw particle diagrams for a solid, liquid, and a gas using at least 5 particles: b. Which has a definite shape? HCl(g) H2O(l) Cu(s) c. Which has a definite volume? LiF(g) Br2(l) Mg(s) 12. Vapors are the gas phase of substances that are normally solid or liquid at room temperature. Which can be a vapor?
Carbon dioxide ______ Water _____ Oxygen _____
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13. Phase changes occur when heat is given to or taken from a sample. For each of the following, give the phases involved and if it is endothermic or exothermic. Evaporation ___________________________ __________________________ Melting ___________________________ __________________________ Deposition ___________________________ __________________________ Boiling ___________________________ __________________________ Condensation ___________________________ __________________________ Sublimation ___________________________ __________________________ CHANGES IN THE LAB 14. Physical changes are changes where the substance retains its properties. Chemical changes will make substances change into new substances and change properties. a. Label the following as physical (P) or chemical (C) properties: Texture ____ flammability ____ boiling point: ____ Odor ____ color ____ chemical composition: ____ b. Label the following as physical (P) or chemical (C) changes: Corrosion: ____ melting: ____ mixing: ____ Freezing: ____ cutting: ____ decaying: ____
