SL Chemistry. Friday August 21st Sunday, August 23, 15

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1 SL Chemistry Friday August 21st 2015

2 Agenda Warm Up: Balancing Chemical Equations Continue Topic 1.1: Introduction to the Particulate Nature of Matter & Chemical Change Exit Ticket: Topic 1.1 Check

3 Warm Up You have 10 minutes ONLY! GO! Using that handout, work with a partner to balance all of the equations.

4 Practice Problem 15 mins... You Do... Working with a partner, balance the equations for the following chemical reactions and include the state symbols. 1. CaCO3 + HCl > CaCl2 + CO2 + H2O 2. CrO3 > Cr2O3 + O2 3. PH3 + O2 > P4O10 + H2O 4. Al4C3 + H2O > CH4 + Al2O3

5 HOMEWORK Topic 1.1 Introduction to Particulate Nature of Matter & Chemical Change vocabulary DUE September 4th 2015 No Exceptions! Balancing chemical equations worksheet - Due 8/24

6 Topic 1.1 Introduction to the Particulate Nature of Matter and Chemical Change Atoms of different elements combine in fixed ratios to form compounds, which have different properties from their component elements. Mixtures contain more than one element and/or compound that are not chemically bonded together and so retain their individual properties. Mixtures are either homogeneous or heterogeneous.

7 Introduction to the Particulate Nature of Matter and Chemical Change Common Polyatomic Ions Name of polyatomic ion Formula Name of polyatomic ion Formula ammonium ion NH4 + phosphate (V) ion PO4 3- carbonate ion CO3 2- phosphonate ion PO3 3- hydrogencarbonate ion HCO3 - sulfate (VI) ion SO4 2- hydroxide ion OH - sulfate ion SO3 2- nitrate (V) ion NO3 2- ethanedioate ion C2O4 2- nitrate (III) ion NO2 - peroxide ion O2 2-

8 Introduction to the Particulate Nature of Matter and Chemical Change Common acids Naming anions Name of acid Formula Name of Anion Formula Naming Suffix hydrochloric acid HCl sulfide ion S 2- -ide nitric (V) acid HNO3 sulfate (VI) ion SO4 2- -ate phosphoric (V) acid H3PO4 sulfate (IV) SO3 2- -ate sulfuric (VI) acid ethanoic acid H2SO4 CH3COOH

9 Introduction to the Particulate Nature of Matter and Chemical Change Some reaction types Combination or Synthesis reactions involve the combination of two or more substances to produce a single product: C(s) + O2(g) --> CO2(g) Decomposition reactions involve a single reactant being broken down into two or more products: CaCO3(s) --> CaO(s) + CO2(g) Single Replacement reactions occur when one element replaces another in a compound. An example of this type of reaction is a redox reaction: Mg(s) + 2HCl(aq) --> MgCl2(s) + H2(g) Double Replacement reactions occur between ions in solution to form insoluble substances and weak non-electrolytes, also termed metathesis reactions: HCl(aq) + NaOH(aq) --> NaCl(aq) + H2O(l)

10 List of Diatomic Molecules Diatomic molecules contain 2 atoms of said element... They cannot contain just 1! Di = 2 Chlorine Cl2, Bromine Br2, Fluorine F2, Iodine I2, Oxygen O2, Nitrogen N2, and Hydrogen H2.

11 Write down your given equation. For this example, you will use: C3H8 + O2 --> H2O + CO2 This reaction occurs when propane (C3H8) is burned in the presence of oxygen to produce water and carbon dioxide.

12 Write down the number of atoms per each element that you have on each side of the equation. Look at the subscripts next to each atom to find the number of atoms in the equation. Left side: 3 carbon, 8 hydrogen and 2 oxygen. Right side: 1 carbon, 2 hydrogen and 3 oxygen.

13 Always leave hydrogen and oxygen for last.

14 If you have more than one element left to balance: select the element that appears in only a single molecule of reactants and in only a single molecule of products. This means that you will need to balance the carbon atoms first.

15 Add a coefficient to the single carbon atom on the right of the equation to balance it with the 3 carbon atoms on the left of the equation. C3H8 + O2 --> H2O + 3CO2 The coefficient 3 in front of carbon on the right side indicates 3 carbon atoms just as the subscript 3 on the left side indicates 3 carbon atoms. In a chemical equation, you can change coefficients, but you must never alter the subscripts.

16 Balance the hydrogen atoms next. You have 8 on the left side. So you'll need 8 on the right side. C3H8 + O2 --> 4H2O + 3CO2 On the right side, you now added a 4 as the coefficient because the subscript showed that you already had 2 hydrogen atoms. When you multiply the coefficient 4 times by the subscript 2, you end up with 8. The other 6 atoms of Oxygen come from 3CO2.(3x2=6 atoms of oxygen+ the other 4=10)

Balance the oxygen atoms. Because you've added coefficients to the molecules on the right side of the equation, the number of oxygen atoms has changed.

17 Balance the oxygen atoms. Because you've added coefficients to the molecules on the right side of the equation, the number of oxygen atoms has changed. You now have 4 oxygen atoms in the water molecule and 6 oxygen atoms in the carbon dioxide molecule. That makes a total of 10 oxygen atoms. Add a coefficient of 5 to the oxygen molecule on the left side of the equation. You now have 10 oxygen molecules on each side. C3H8 + 5O2 --> 4H2O + 3CO2.

18 The carbon, hydrogen, and oxygen atoms are balanced. Your equation is complete.

19 Practice Problem 15 mins... You Do... Working with a partner, balance the equations for the following chemical reactions and include the state symbols. 1. CaCO3 + 2HCl > CaCl2 + CO2 + H2O 2. 4CrO3 > 2Cr2O3 + 3O2 3. 4PH3 + 8O2 > P4O10 + 6H2O 4. Al4C3 + 6H2O > 3CH4 + 2Al2O3

20 Topic 1.1 Check: Answer the following questions in your notebook: Describe one example of a compound that reacts differently than its parts (other than what we talked about in class) Balance the following chemical equation, including state symbols and explain the importance of balancing equations Describe the difference between an element, compound, and a mixture. Explain the difference between a homogeneous and heterogeneous mixture... Give an example of both.

21 Topic 1.1 Introduction to the Particulate Nature of Matter and Chemical Change Atoms of different elements combine in fixed ratios to form compounds, which have different properties from their component elements. Mixtures contain more than one element and/or compound that are not chemically bonded together and so retain their individual properties. Mixtures are either homogeneous or heterogeneous.

22 Stoichiometric Relationships Introduction to the Particulate Nature of Matter and Chemical Change The Mole Concept Reacting Masses and Volumes Ms. Thompson - SL Chemistry Wooster High School

23 Topic 1.2 The Mole Concept The mole is a fixed number of particles and refers to the amount, n, of substance. Masses of atoms are compared on a scale relative to 12 C and are expressed as relative atomic mass (A r ) and relative formula/molecular mass (M r ). Molar mass (M) has the units g mol -1. The empirical formula and molecular formula of a compound give the simplest ratio and the actual number of atoms present in a molecule respectively.

24 The Mole Concept SI: the international system of measurement Property Unit Symbol mass kilogram kg temperature kelvin K time second s amount mole mol electric current ampère A luminosity candela cd length metre m The International Bureau of Weights and Measures (BIPM) monitors the correct use of SI units and ensures consistency regardless of where they being used.

25 Know these! The Mole Concept Avogadro s Constant (NA) 6.02 x mol -1 Molar volume of an ideal gas at 273K and 100kPa 2.27 x 10-2 m 3 mol -1 (=22.7 dm 3 mol -1 ) Negative indices and units An index or power is a mathematical notation that shows that a quantity or physical unit is repeatedly multiplied by itself: m x m = m 2 A negative index shows a reciprocal 1/x = x -1 dm -3 = 1/dm Useful Prefixes Prefix Abbreviation Scale nano n 10-9 micro μ 10-6 milli m 10-3 centi c 10-2 deci d 10-1 standard - 1 kilo k 10 3 mega M 10 6 giga G 10 9

26 The Mole Concept Amount of substance: The mole The ability to measure precise amounts of reacting substances is of crucial importance. All chemical substances are made up of elements and their constituent atoms which vary in their number of protons, neutrons, and electrons

The Mole Concept Amount of substance: The mole Had to determine a way to measure equal amounts of different elements regardless of how big their atoms are which tells us how

27 The Mole Concept Amount of substance: The mole Had to determine a way to measure equal amounts of different elements regardless of how big their atoms are which tells us how much reacting quantities we have The mole is an SI unit, symbol mol, defined as a fixed amount, n, of a substance. This is known as Avogadro s constant = 6.02 x mol -1

28 The Mole Concept Relative atomic mass, relative formula mass, and molar mass Isotopes are atoms of the same element that have the same number of protons in nucleus but different numbers of neutrons. Relative abundance is how much of that element occurs and influences the atomic mass of the atom. Relative atomic mass (Ar) is the average of the different isotopes and their masses. Relative molecular mass (Mr) is determined by combining the Ar values of the individual atoms or ions. Molar Mass mass of one mole of a substance in grams per mole (g mol -1 )

29 Practice Problem... I Do... State the relative atomic mass Ar of aluminum. 13 Al

30 Practice Problem... We Do... Calculate the molar mass (Mr) of sulfuric acid H2SO H S O

31 Practice Problem... You Do... Calculate Mr of copper (II) sulfate pentahydrate, CuSO4 º 5H2O Cu S H O

32 HOMEWORK Topic 1.1 Introduction to Particulate Nature of Matter & Chemical Change vocabulary DUE September 4th 2015 No Exceptions! Balancing chemical equations handout - Due 8/24

Stoichiometric Relationships

Stoichiometric Relationships Introduction to the Particulate Nature of Matter and Chemical Change Reacting Masses and Volumes Ms. Thompson - SL Chemistry Wooster High School Topic 1.2 The mole is a fixed