Compounds Names and Formulas

Transcription

1 Compounds Names and Formulas This is where it s at John! 0803 Chapter 4.3 1

2 Compounds Names and Formulas Just like elements, compounds have names that distinguish them from other compounds. Being able to figure out the formula from a name, and the name from a formula is a SKILL that is VITAL in chemistry. Stay in school bayyyy-beee! 0803 Chapter 4.3 2

3 Naming ionic compounds are pretty easy! Remember, a ionic compound consists of a cation (positive charge) and a anion (negative charge). The cation is always listed first. It is usually just the name of the element! Did you ever hear of Einstein Albert? No? The order of a name is important, whether it be a person or a compound Chapter 4.3 3

4 The anion name is placed after the cation. In most cases, you will replace the ine ending that most anions with ide. Here are some examples Fluorine Chlorine Bromine Iodine Oxygen Sulfur Nitrogen Fluoride Chloride Bromide Iodide Oxide Sulfide Nitride 0803 Chapter 4.3 4

5 Let s try a few examples What compound would you get if you reacted sodium with bromine? Sodium bromide Fluorine Chlorine Bromine Iodine Oxygen Sulfur Nitrogen Fluoride Chloride Bromide Iodide Oxide Sulfide Nitride 0803 Chapter 4.3 5

6 Let s try a few examples What compound would you get if you reacted calcium with chlorine? Calcium chloride Fluorine Chlorine Bromine Iodine Oxygen Sulfur Nitrogen Fluoride Chloride Bromide Iodide Oxide Sulfide Nitride 0803 Chapter 4.3 6

7 Let s try a few examples How about Potassium with oxygen? Potassium oxide Fluorine Chlorine Bromine Iodine Oxygen Sulfur Nitrogen Fluoride Chloride Bromide Iodide Oxide Sulfide Nitride 0803 Chapter 4.3 7

8 Let s try a few examples Cesium and sulfur? Cesium sulfide Fluorine Chlorine Bromine Iodine Oxygen Sulfur Nitrogen Fluoride Chloride Bromide Iodide Oxide Sulfide Nitride 0803 Chapter 4.3 8

9 Let s try a few examples Last, how about Magnesium and Nitrogen? Magnesium nitride Remember, use this naming method when combining a cation and a anion. Fluorine Chlorine Bromine Iodine Oxygen Sulfur Nitrogen Fluoride Chloride Bromide Iodide Oxide Sulfide Nitride 0803 Chapter 4.3 9

10 Many times, the cation is a transition metal (remember those pesky little things in the middle of the periodic table)? 0803 Chapter

11 Because the transition metals can have different positive charges, you must include the charge in the compound name using roman numerals. Your not rid of me yet! In order for you to do this, you must know the charge on the anion! 0803 Chapter

12 Let s say you have a compound that contains Iron and chlorine. The chemical formula might be FeCl 2 What is the anion charge of Cl in this compound. If you look at the Periodic Table, Cl has a valence of Chapter

13 Let s say you have a compound that contains Iron and chlorine. The chemical formula might be FeCl 2 What is the anion charge of Cl in this compound. If you look at the Periodic Table, Cl has a valence of -1. There are two chlorine atoms in each unit of the compound. That means the total anion charge is 2+. To make this compound electrically neutral, what must the charge on Iron be? 0803 Chapter

14 Let s say you have a compound that contains Iron and chlorine. The chemical formula might be FeCl 2 Fe must be 2+ to counter-balance the 2- from chlorine. That s the hard part. Now it s time to name it. We must state the charge on Iron in the name using roman numerals Chapter

15 Let s say you have a compound that contains Iron and chlorine. The chemical formula might be FeCl 2 Iron (II) Chloride Place the roman numerals in parenthesis. It is important to remember that anytime you have a transition metal in an ionic compound, you must state the charge Chapter

16 Let s try another one NiO The charge of oxygen is ALWAYS 2-. Since the ratio is one to one, nickel must have a charge of 2+ So the name would be Nickel (II) oxide Chapter

17 How about CrF 3 First figure out the charge on Chromium. Chromium (III) Fluoride 0803 Chapter

18 Next CuBr 2 The answer is Copper (II) Bromide 0803 Chapter

19 Last easy one CdO The answer is Cadmium (II) oxide 0803 Chapter

20 This one is a little bit trickier Fe 2 O 3 What is the charge on EACH iron atom? First figure out the total anion charge. There are 3 oxygen atoms in this compound, each with a charge of 2-. That means the total charge is 6-. Since there are 2 iron atoms, what is the charge of each? Fe is 3+ so the name is Iron(III) oxide 0803 Chapter

21 You can use the cross charge technique on this and many other compounds. Fe 2 O 3 Take the number of atoms of the anion and use it as the charge on the cation Chapter

22 You can use the cross charge technique on this and many other compounds. 3+ Fe 2 O 3 Take the number of atoms of the anion and use it as the charge on the cation Chapter

23 Let s try another of these cross charge compounds Ni 2 S 3 Use the cross charge technique to figure out the charge of the nickel Ni is 3+ so the name is Nickel(III) sulfide 0803 Chapter

24 Last one of these Mn 2 O 7 The answer is Manganese (VII) oxide 0803 Chapter

25 Naturally, you will at times have to go the other way. If you start with a compound name, you will have figure out the chemical formula. You just have to think in reverse. Let s try one Barium Fluoride What is the chemical formula for the above compound? 0803 Chapter

26 Barium Fluoride First, figure out the charge on each ion. Barium is a 2+.Fluorine is a 1-. You would need two fluorines to equalize the 2+ from barium. The chemical formula would be BaF Chapter

27 What would the chemical formula be for Calcium Oxide Look up the charges of each ion Ca is 2+, O is 2- You might be tempted to put Ca 2 O Chapter

28 You might be tempted to put Ca 2 O 2 Calcium Oxide But if you can reduce the numbers, do so CaO 0803 Chapter

29 What would the chemical formula be for Iron (II) oxide We already know iron is a +2 (roman numerals), and since oxygen is -2, you need one of each. FeO 0803 Chapter

30 What would the chemical formula be for Iron (III) oxide The answer is. Fe 2 O Chapter

31 Remember that charge crossing thing? It works in reverse too! Iron (III) oxide Fe 2 O Chapter

32 What would the chemical formula be for Copper (IV) sulfide The answer is. CuS Chapter

33 Turn to page 122 in your book to see a table of polyatomic ions. See if you can figure out the chemical formula for the following ionic compounds Sodium Carbonate Note that when you see an ate or an ite ending, it s usually a polyatomic ion and not a single element (remember, single anions The usually answer end in ide. is. Na 2 CO Chapter

34 Here s another compound with a polyatomic ion in it. Remember to keep the polyatomic ions together as a group! If you need more than one, put them in parenthesis! Potassium nitrate The answer is. KNO Chapter

35 Here s another one Calcium hydroxide Don t let that ide ending fool you. It s a polyatomic ion The answer is. Ca(OH) Chapter

36 Here s another one Calcium phosphate The answer is. Ca 3 (PO 4 ) Chapter

37 Ban Dihydrogen Monoxide!!! Join the Movement to BAN this DANGEROUS and deadly chemical!!! 0803 Chapter

38 0803 Chapter

39 Covalent Compound Names OK. Now on to last naming category covalent compounds. Remember, covalent bonds are formed from two or more nonmetals (anions). When naming these compounds, you must use prefixes Chapter

40 Covalent Compound Names Page 126 has a table of the prefixes you will use Number of atoms Prefix 1 Mono 2 Di 3 Tri 4 Tetra 5 Penta 6 Hexa 7 Hepta 8 Octa 9 Nona 10 deca 0803 Chapter

41 Covalent Compound Names Here is an example of a covalent chemical Dihydrogen monoxide What is the chemical formula of this compound? H 2 O Number of atoms Prefix 1 Mono 2 Di 3 Tri 4 Tetra 5 Penta 6 Hexa 7 Hepta 8 Octa 9 Nona 10 deca 0803 Chapter

42 Covalent Compound Names When you are naming covalent compounds, list them in left to right order as they appear in the periodic table. If there is only one atom in the first element, you don t need to use the prefix mono. Number of What is the name of this compound? N 2 O Dinitrogen monoxide atoms Prefix 1 Mono 2 Di 3 Tri 4 Tetra 5 Penta 6 Hexa 7 Hepta 8 Octa 9 Nona 0803 Chapter deca 42

43 Covalent Compound Names What is the name of this compound? CO Carbon monoxide Number of atoms Prefix 1 Mono 2 Di 3 Tri 4 Tetra 5 Penta 6 Hexa 7 Hepta 8 Octa 9 Nona 0803 Chapter deca 43

44 Covalent Compound Names What is the chemical formula of this compound? Tetraphosphorous decaoxide P 4 O 10 Number of atoms Prefix 1 Mono 2 Di 3 Tri 4 Tetra 5 Penta 6 Hexa 7 Hepta 8 Octa 9 Nona 0803 Chapter deca 44

45 Empirical Formulas The empirical formula is the simplest (reduced) chemical formula of a compound. Tetraphosphorous decaoxide P 4 O 10 Can be reduced to P 2 O 5 This is the empirical formula Chapter

46 Empirical Formulas Wart remover Salad dressing sugar 0803 Chapter

47 Hydrates Hydrates are compounds that have water molecules attached to them. Hydrates have the ability to absorb water into their structure. Hydrates can form in organic and inorganic chemistry Chapter

48 Hydrates Inorganic hydrates have a fixed ratio of water molecules to the salt they are attached to (a salt in chemistry is a metal and non-metal combined, as in an ionic compound). They have the ability to soak up water into their chemical structure Chapter

49 Hydrates They have the ability to soak up water into their chemical structure. You may see this packet of Silica gel. This gel absorbs water. You may have seen these in products that you purchase Chapter

50 Hydrates Sodium Polyacrylate is able to absorb times its weight in water Chapter

51 Hydrates Sodium Polyacrylate is commonly used in diapers (for obvious reasons) Chapter

52 Hydrates Not all ionic compounds have the ability to form hydrates. When you write the formula for a hydrate, you add the water to the end of the formula, along with the number of water molecules attached Chapter

53 Covalent Compound Names The prefixes for the hydrates are the same as are used in covalent compounds. CoCu 2 x 5H 2 0 The name of this compound would be Copper II Chloride pentahydrate Number of atoms Prefix 1 Mono 2 Di 3 Tri 4 Tetra 5 Penta 6 Hexa 7 Hepta 8 Octa 9 Nona 0803 Chapter deca 53

54 Covalent Compound Names The prefixes for the hydrates are the same as are used in covalent compounds. BaCl 2 x 10H 2 0 What is the name of this compound? Barium Chloride decahydrate Number of atoms Prefix 1 Mono 2 Di 3 Tri 4 Tetra 5 Penta 6 Hexa 7 Hepta 8 Octa 9 Nona 0803 Chapter deca 54

55 Covalent Compound Names The prefixes for the hydrates are the same as are used in covalent compounds. What is the chemical formula for Barium Fluoride trihydrate? BaF 2 x 3H 2 0 Number of atoms Prefix 1 Mono 2 Di 3 Tri 4 Tetra 5 Penta 6 Hexa 7 Hepta 8 Octa 9 Nona 0803 Chapter deca 55

56 Review Time!!! To name an ionic compound, first name the cation, then the anion. When an element can form cations with different charges (transition elements), the cation name must include the charge (using roman numerals). Prefixes are used to name covalent compounds made of two different elements. An empirical formula tells the relative numbers (ratios) of atoms of each element in a compound Chapter