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Matter, Measurement, and The Language of Chemistry

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1 Matter, Measurement, and The Language of Chemistry
SAVE PAPER AND INK!!! When you print out the notes on PowerPoint, print "Handouts" instead of "Slides" in the print setup. Also, get rid of background shading by selecting “Pure Black & White” instead of “Grayscale.” Unit 1 Matter, Measurement, and The Language of Chemistry

2 Matter Matter – anything that has mass and occupies space.
Matter can be classified according to its state (solid, liquid or gas.)

3 Matter (continued) Matter can also be classified according to its composition:

4 Matter (continued) Pure Substance – Composed of only a single type of atom or molecule. Element – Composed of only one type of atom. Cannot be chemically broken down into simpler substances. Compound – Composed of two or more elements in fixed, definite proportions. Mixture – Composed of two or more different types of atoms or molecules that can be combined in variable proportions.

5 Heterogeneous Mixtures
A heterogeneous mixture consists of visibly different substances.

6 Homogeneous Mixtures A homogeneous mixture has the same uniform appearance and composition.

7 Properties of Matter Physical Properties – Characteristics of a substance that you can observe. Examples: mass, volume, color, shape, odor, texture, melting point, boiling point, density. Chemical Properties - Characteristics of a substance that describe how it can be changed into a new substance. Examples: flammability, corrosiveness, reactivity, acidity, toxicity.

8 Changes in Matter Physical Change – A change in physical properties, it is still the same substance. Chemical Change – The change of a substance into a new, different substance.

9 Metric Measurement Metric System – The standard measurement system used by scientists around the world. Also called the International System of Units, or SI. It is a decimal system, based on the number 10 and multiples of 10.

10 Length The basic metric unit of length is the meter (m).
A meter is a little longer than a yard.  A meter is a typical height for a 3-year old child, or about the size of two cocker spaniels.

11 Mass The basic metric unit of mass is the gram (g). Mass is measured with a balance. A gram is small. A nickel coin has a mass of about 5 g. To measure larger amounts of mass, a kilogram (kg) is usually used. A kg is bigger than a pound. A 132 lb. person would have a mass of 60 kg.

12 Temperature oC = (oF -32) / 1.8 K = oC + 273
The SI unit for temperature is the kelvin (K). Absolute zero – 0 K (-273oC) the coldest temperature possible, where all molecular motion stops. You can convert between temperature scales with the following formulas: oC = (oF -32) / 1.8 K = oC + 273

13 Volume The basic metric unit of volume is the liter (L).
One milliliter (ml) is the same as one cubic centimeter (cm3.) 2 L is the common size for a bottle of soda. 1 ml doesn’t even fill up a teaspoon.

14 Density Extensive Properties depend on the amount of the substance. Examples: Mass, Volume. Intensive Properties (also called characteristic properties) are independent of the amount of the substance. They can be used to identify substances. Example: Density. Density is the ratio of mass to volume: Density = Mass Volume

15 Significant Figures the non-place-holding digits in a reported measurement are called significant figures. All non-zero numbers are significant, but some zeros in a written number are only there to help you locate the decimal point. How do you remember which zeros are significant and which are not?

16 Significant Figures The Atlantic – Pacific Rule: Pacific (Present) -
If decimal point is present, start with the first non-zero number on the left. Atlantic (Absent) - If decimal point is absent, start with the first non-zero number on the right.

17 Significant Figures Examples: How many significant figures? 99,000
2 sig figs 99,000. 5 sig figs 0.0099 2 sig figs 0.0990 3 sig figs

18 Calculating with Significant Figures
When you use your measurements in calculations, your answer may only be as exact as your least exact measurement. For addition and subtraction, round to the fewest decimal places. Example: (3 decimals) (1 decimal) (unrounded) (rounded) = 67.7 For multiplication and division, round to the fewest significant figures. Example: (3 sigfigs) (1 sigfig) (unrounded) (rounded) x = 3

19 Uncertainty in Measurement
Uncertainty comes from limitations of measuring devices, experimental design, experimenter, and nature’s random behavior. Accuracy – how close a measurement comes to the actual value. Precision – how close measurements are to one another, or how reproducible they are. Not Accurate and Not Precise Accurate but Not Precise Not Accurate but Precise Accurate and Precise

20 Accuracy vs. Precision

21 Chemical Formulas octane — C8H18 aluminum sulfate — Al2(SO4)3
A chemical formula indicates the number of each kind of atom in a chemical compound. when there is no subscript next to an atom, the subscript is understood to be 1. Examples: octane — C8H18 aluminum sulfate — Al2(SO4)3 there are 18 hydrogen atoms in the molecule. there are 8 carbon atoms in the molecule. Parentheses surround the polyatomic ion to identify it as a group. There are 3 SO4- groups. there are 2 aluminum atoms in the formula unit.

22 Chemical Formulas Sample Problem
Count the number of atoms in the following chemical formulas: Solution: Ca(OH)2 KClO3 NH4OH Fe2(CrO4)3 1 Calcium, 2 Oxygens, and 2 Hydrogens 1 Potassium, 1 Chlorine, and 3 Oxygens 1 Nitrogen, 5 Hydrogens, and 1 Oxygen 2 Irons, 3 Chromiums, and 12 Oxygens

23 Metals and Nonmetals Metals tend to form positive (+) ions, Nonmetals tend to form negative (-) ions.

24 Monoatomic Ions Monoatomic Ions are ions formed from a single atom.
Some main-group elements tend to form covalent bonds instead of ions (ex. C and Si.) +1 +2 +3 -3 -2 -1

25 Monoatomic Ions Sample Problem
Identify each element as either a metal or a nonmetal. For main group elements, specify the ion that will form: Metal or Nonmetal: Ion: Na Cu O Au Ba H N Al metal +1 metal nonmetal -2 metal metal +2 nonmetal +1 nonmetal -3 metal +3

26 Chemical Categories by Formula
Ionic Compounds – Formed from metal (+) ions and nonmetal (-) ions. Base – formula ends with the hydroxide ion (OH-1) (ex. KOH, Ca(OH)2, Al(OH)3) Metallic Oxide – consists of only 2 elements: 1 metal and oxygen (ex. Na2O, MgO, SnO2) Oxysalt – contains the element oxygen in the form of a polyatomic ion (ex. MgSO3, Ni(ClO3)2) Salt – an ionic compound that can’t be classified into a more specific category (ex. NaCl, CuBr2)

27 Chemical Categories by Formula (continued)
Molecular Compounds – Formed from two or more nonmetals. Non-metallic Oxide – consists of only 2 elements: 1 nonmetal and oxygen (ex. CO2, SO3, P4O10) Hydrocarbon – consists of only 2 elements: carbon and hydrogen (ex. CH4, C2H4, C3H8) Acids – formula begins with hydrogen (H+). Binary acid – contains hydrogen and one other element (ex. HCl, H2S, HBr) Oxyacid – contains oxygen in a polyatomic ion (ex. HNO3, H2SO4, H3PO4)

28 Chemical Categories by Formula Sample Problem
To which category does each of the following chemical formulas belong?: Category: BaSO3 Ag2O Ca(OH)2 NiF2 C4H10 HNO2 PO5 HF oxysalt metallic oxide base salt hydrocarbon oxyacid nonmetallic oxide binary acid

29 Nomenclature Flowchart
Compounds Compounds Ionic Ionic Molecular Acids Prefix System Hydro-carbons Binary Acids Oxyacids Binary Binary Hydrates Polyatomic Ions

30 Naming Binary Ionic Compounds
Binary Compounds are composed of 2 elements. The name of the metal (+) ion is given first, followed by the name of the nonmetal (-) ion. The first element in the compound is identified simply by its name. For the second element, the ending of the its name is dropped, and the ending -ide is added. Examples: Al2O3 aluminum oxide KF potassium fluoride

31 Writing Binary Ionic Compounds
Rules for writing binary ionic compounds: Write the symbols for the ions, and their charges. Remember: The metal (+) ion is always written first. Cross over the charges (use the absolute value of each ion’s charge as the subscript for the other ion.) Simplify the numbers and remove the 1’s. Example: aluminum oxide The correct formula for aluminum oxide is Al3+ O2– 2 3 Al2O3

32 Binary Ionic Compounds Sample Problem
Write chemical formulas for : Magnesium Iodide Calcium Oxide Write the correct names for: Li2S ZnCl2 Solution: Mg2+ I – MgI2 1 2 Ca2+ O 2– CaO 2 2 Hint: Always divide subscripts by their largest common factor . Lithium Sulfide Lithium Zinc Chloride Zinc

33 The Stock System Most d-block elements (transition metals) can form 2 or more ions with different charges. To name ions of these elements, scientists use the Stock system, designed by Alfred Stock in 1919. The system uses Roman numerals to indicate an ion’s charge. Example: Fe2+ Fe3+ iron(II) iron(III)

34 Stock System Naming Sample Problem A
Write the formula and give the name for the compound formed by the ions Cr3+ and F–. Solution: Write the ions side by side, cation first. Cross over the charges to give subscripts. Chromium forms more than one ion, so its name must include the charge as a Roman numeral. Cr3+ F – 1 3 CrF3 Chromium (III) Fluoride

35 Stock System Naming Sample Problem B
Write chemical formulas for : Tin (IV) Iodide Iron (III) Oxide Write the correct names for: VF3 CuO Solution: Sn4+ I – SnI4 1 4 Fe3+ O 2– Fe2O3 2 3 3+ - V F3 Vanadium (III) Fluoride 2 + - 2 Cu O Copper (II) Oxide Hint: “Uncross” subscripts to get the charges of the ions. Be sure to verify the charge of the anion.

36 Nomenclature Flowchart
Compounds Compounds Ionic Ionic Molecular Acids Prefix System Hydro- carbons Binary Acids Oxyacids Binary Hydrates Polyatomic Ions Polyatomic Ions

37 There are 3 sulfate ions in this compound
Polyatomic Ions Common Polyatomic Ions A polyatomic ion is a charged group of covalently bonded atoms. Common endings are -ate or -ite, but there are exceptions. For more than 1 polyatomic ion, use parentheses with the subscript on the outside. Example: Al2(SO4)3 There are 3 sulfate ions in this compound

38 Polyatomic Ions Sample Problem
Write chemical formulas for : Calcium Hydroxide Tin (IV) Sulfate Write the correct names for: (NH4)3 PO4 Cu(NO3)2 Solution: Ca2+ OH – Ca(OH)2 1 2 Sn4+ SO4 2– Sn(SO4)2 2 4 Hint: Remember to divide subscripts by their largest common factor . Ammonium Phosphate - 2+ Cu (NO3)2 Copper(II) Nitrate Hint: “Uncross” subscripts to get the charges of the ions.

39 Nomenclature Flowchart
Compounds Compounds Ionic Ionic Molecular Acids Prefix System Hydro- carbons Binary Acids Oxyacids Binary Hydrates Hydrates Polyatomic Ions

40 Hydrates Prefix No. of Waters hemi mono 1 di 2 tri 3 tetra 4 penta 5 hexa 6 hepta 7 octa 8 Hydrates – ionic compounds that contain a specific number of water molecules associated with each formula unit. in formula, attached waters follow. in name, attached waters indicated by adding “prefixhydrate” after name of ionic compound. Example: CoCl2∙ 6H2O cobalt(II) chloride hexahydrate

41 Hydrates Sample Problem
Write chemical formulas for : calcium sulfate hemihydrate barium chloride hexahydrate Write the correct names for: CuSO4 • 5H2O LiF • 4H2O Solution: CaSO4 • ½ H2O BaCl2 • 6H2O copper (II) sulfate pentahydrate lithium fluoride tetrahydrate

42 Nomenclature Flowchart
Compounds Compounds Ionic Molecular Molecular Acids Prefix System Prefix System Hydro- carbons Binary Acids Oxyacids Binary Hydrates Polyatomic Ions

43 The Prefix System Molecular compounds are composed of covalently-bonded molecules. The old prefix system is still used for molecular compounds. Name the prefix, then the element. Anions end in -ide. The prefix mono- usually isn’t used for cations. Examples: P4O CO tetraphosphorus decoxide carbon monoxide

44 The Prefix System Sample Problem
Write chemical formulas for : dinitrogen trioxide carbon tetrabromide Write the correct names for: As2S3 PCl5 Solution: N2O3 CBr4 diarsenic trisulfide phosphorus pentachloride

45 Nomenclature Flowchart
Compounds Compounds Ionic Molecular Molecular Acids Prefix System Hydro- carbons Hydro- carbons Binary Acids Oxyacids Binary Hydrates Polyatomic Ions

46 Hydrocarbons Hydrocarbons are compounds that contain only carbon and hydrogen. Most fuels are mixtures of hydrocarbons. Hydrocarbons containing only single bonds are called alkanes. Naming is based on the number of carbons , and the suffix –ane is added. Base Name No. of C meth- 1 hex- 6 eth- 2 hept- 7 prop- 3 oct- 8 but- 4 non- 9 pent- 5 dec- 10

47 Hydrocarbons Sample Problem
Write chemical formulas for : methane butane Write the correct names for: C2H6 C3H8 Solution: CH4 C4H10 ethane propane

48 Nomenclature Flowchart
Compounds Compounds Ionic Molecular Acids Acids Prefix System Hydro- carbons Binary Acids Binary Acids Oxyacids Oxyacids Binary Hydrates Polyatomic Ions

49 Acids An acid is a certain type of molecular compound. All acids start with H (e.g. HCl, H2SO4). Acids can be divided into two categories: Binary acids are acids that consist of H and a non-metal. (e.g. HCl.) Oxyacids are acids that contain H and a polyatomic ion that includes O (e.g. H2SO4.)

50 Binary Acids General rules for naming a binary acid:
Begin with the prefix hydro-. Name the anion, but change the ending to –ic. Add acid to the name. Examples: HCl, hydrochloric acid. HBr, hydrobromic acid. H2S, hydrosulfuric acid.

51 Oxyacids General rules for naming an oxyacid :
Name the polyatomic ion. Replace -ate with -ic or -ite with -ous Add acid to the name. Examples: H2SO4, sulfuric acid. H2SO3, sulfurous acid. HNO3, nitric acid. HNO2, nitrous acid.

52 Naming Acids Sample Problem
Write the correct name for each of the following: HF HNO2 H2S H2SO4 H3PO4 Type of Acid: Name: binary acid hydro fluorine ic acid oxyacid nitrite ous acid binary acid hydro sulfur ic acid oxyacid sulfate uric acid oxyacid phosphate oric acid

53 Heat and Temperature Temperature – a measure of the average kinetic energy of the particles in a sample of matter. The greater the kinetic energy of the particles in a sample, the hotter it feels. Heat – energy transferred between samples of matter due to a difference in their temperatures. Heat always moves spontaneously from matter at a higher temperature to matter at a lower temperature.

54 Measuring Heat Heat energy is measured in joules (or calories – food only) Chemical reactions usually either absorb or release energy as heat. The energy absorbed or released as heat in a chemical or physical change is measured in a calorimeter.

55 Specific Heat A quantity called specific heat can be used to compare heat absorption capacities for different materials. Specific heat – the amount of energy required to raise the temperature of one gram of a substance by 1°C or 1 K. Specific heat can be measured in units of J/(g•°C), J/(g•K), cal/(g•°C), or cal/(g•K).

56 Heat Transfer Equation
Specific heat can be used to find the quantity of heat energy gained or lost with a change in temperature according to the following equation: Where the variables stand for the following: Q = heat transferred (joules or calories) m = mass (g) cp = specific heat ∆T = change in temperature (oC or K) Q = m•cp•∆T

57 Heat Transfer Equation Sample Problem
A 4.0 g sample of glass was heated from 274 K to 314 K, a temperature increase of 40. K, and was found to have absorbed 32 J of energy as heat. What is the specific heat of this type of glass? b. How much energy will the same glass sample gain when it is heated from 314 K to 344 K? 32 J Q = m x cp x ∆T cp = = 0.20 J/(g•K) (4.0 g) (40. K) 32 J = (4.0 g) (cp) (40. K) Q = m x cp x ∆T Q = (4.0 g) (0.20 J/(g•K)) (30 K) = 24 J


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