Chemical Equations and Reactions



Information Symbols And “Phase Notation” (state) Name: ____________________________

Instructions: Use the appropriate information symbols and phase notation (s, l, or g for solid, liquid, gas) to describe these chemical events. Be sure to include an arrow to show the separation of reactants from products.

–Use correct formulas for ionic compounds and molecular compounds.

–Use correct symbols for elements…watch for the 7 diatomic molecular elements.

–When told “soluble”, or “in solution” it means, “dissolved in an aqueous solution” (use “aq”).

–When told “insoluble”, or “precipitated”, it means, “forms a solid unable to stay dissolved” (use “s”).

–The symbols for heat (∆) and/or for any catalyst should be written over the arrow. A catalyst is a chemical that speeds up a chemical reaction; but, it remains unchanged – so it is neither a reactant nor a product.

–Use a double ended arrow for reversible reactions.

–Assume water is in the liquid state unless told otherwise; but, “vapor” means it is in the gaseous state.

Refer to Table 11.1 in your text book (and information on pp 323) as needed. As well as writing the correct chemical symbols and chemical formulas, also insert the correct information symbols in the partial chemical equations described below. Include an arrow, indicating your understanding of whether the given chemicals are reactants or products

1. Aqueous C6H12O6 is heated: example answer: C6H12O6 (aq) (

2. After heating, water vapor is produced: ___________________________________________________

3. Nickel is used as a catalyst: ___________________________________________________

4. One reactant is hydrogen sulfide: ___________________________________________________

5. A precipitate of sodium sulfide formed: ___________________________________________________

6. Carbon dioxide gas is bubbled through a chemical:___________________________________________

7. Liquid H2O decomposes into its 2 gaseous elements___________________________________________

9. produces a solution of sodium hydroxide:__________________________________________________

10. solid diphosphorus pentoxide is a catalyst___________________________________________________

11. producing a precipitate of iron(III) nitrate ___________________________________________________

12. gaseous hydrogen sulfide is bubbled through:____________________________________________

13. a potassium hydroxide solution: _____________________________________________________

14. produces a potassium sulfide precipitate and water. ______________________________________

15. solid aluminum combines with an aqueous solution of copper(II) fluoride:

____________________________________________________________________________________

16. to produce soluble aluminum fluoride and a precipitate of copper:

____________________________________________________________________________________

Convert the following word equations into balanced chemical equations by the following 3-step method:

-Step “A”, write the unbalanced chemical equation; focus on determining the correct formulas for the compounds and the correct symbols for the elements. Use your periodic table and the list of polyatomic ions; “drop / swap / and simplify” as needed. Watch for the presence of the 7 diatomic molecular elements.

-Step “B’, balance the chemical equation.

-Step “C”, insert the proper informational symbols. Ex: (s), (g), (aq), (l)

17. Gaseous hydrogen sulfide is bubbled through a potassium hydroxide solution producing a potassium sulfide precipitate and water.

A.

B.

C.

18. Aluminum will combine with an aqueous solution of copper(II) fluoride to produce soluble aluminum fluoride and a precipitate of copper.

A.

B.

C.

19. The two reactants, aqueous sodium hydroxide and aqueous phosphoric acid produce water and aqueous sodium phosphate.

A.

B.

C.

20. When aqueous cobalt(III) chloride reacts with aqueous lithium hydroxide, the two products are aqueous lithium chloride and a precipitate of cobalt(III) hydroxide.

A.

B.

C.

21. When aqueous rubidium hydroxide reacts with aqueous phosphoric acid, the two products are water and aqueous rubidium phosphate.

A.

B.

C.

22. When aqueous sodium carbonate reacts with aqueous tin(II) nitrate, the two products are aqueous sodium nitrate and a precipitate of tin(II) carbonate.

A.

B.

C.

23. When solid potassium reacts with aqueous AgNO3, the two products are aqueous potassium nitrate and a precipitate of silver.

A.

B.

C.

24. When nitrogen trifluoride is the one reactant in a decomposition reaction, it decomposes to produce the two elements nitrogen and fluorine.

A.

B.

C.

Predicting Products of Combustion, Double Replacement, and Single Replacement reactions:

1. Combustion Reactions: Since we are assuming “complete combustion” and that the fuel is a “hydrocarbon”, the products of a combustion reaction will only be “____CO2 + ____H2O”. Then balance!

Ex: Given “___CH4 + ___O2” Final answer = 1 CH4 + 2 O2 ( 1 CO2 + 2 H2O

Practice:

_______C3H8 + _______O2 ( ________________+ ___________________

______ C2H6 + _______ O2 ( ________________ + __________________

______C5H12 + _______O2 ( ________________+ ___________________

2. Double Replacement Reactions: Exchange the 2 cations. CAREFUL! You should always do “drop/swaps” for each new product; otherwise, it is unlikely that you will have correct chemical formulas.

(Use your periodic table and polyatomic ion list in order to get the 4 correct charges.) See Steps # 1 – 4 below:

______ NaNO3 + ______ Al2S3 ( _______________ + ____________________

Step 1: Exchange the two cations: Move “Na” into the second compound. Move “Al” into the first compound. Now, it might look like this: ( Al NO3 + Na S but, neither formula is correct.

Step 2: Find and write down the charge of Al (by looking on the periodic table). Find and write down the charge of (NO3) by looking at your polyatomic ion list. Do the same for Na and for S

Now it might look like this: ( Al3+ (NO3)1- + Na1+ S 2-

Step 3: Do the drop/swap (and simplify if necessary). Now it might look like this: Al(NO3)3 + Na2S

Last, balance the whole equation.

Step 4: End result: 6 NaNO3 + 1 Al2S3 ( 2 Al(NO3)3 + 3 Na2S

Practice:

______ NaNO3 + ______ Al2S3 ( _______________ + ____________________

______ CaSO4 + ______ HCl ( _______________ + ____________________

______ (NH4)3P + ______ BaBr2 ( _______________ + ____________________

3. Single Replacement Reactions: You will see “1 element” + “1 compound”.

If the 1 element is a metal, exchange the metal with the cation in the compound. If “H” is the cation, remember, when written in elemental form (as an element), H exists a diatomic molecule.

-Example with a metal: Given, “__Ca + __ AgNO3”

Step 1: Since Ca is a metal, exchange it with Ag: “ ( Ag + Ca NO3”

Step 2: Find the charges for the two ions in the new compound. ( Ag + Ca2+ (NO3)1-

Step 3: Do the drop/swap/simplify if needed: ( Ag + Ca(NO3)2

Step 4: Balance the entire equation: 1 Ca + 2 AgNO3 ( 2 Ag + 1 Ca(NO3)2

Practice:

_____Mg + _____ HCl ( _______________ + ____________________

_____ Na + _____ CaCl2 ( ______________ + ____________________

_____ Al + _____ AgNO3 ( ____________ + ____________________

______Ba + _____ ZnSO4 ( _____________ + ____________________

If the 1 element is a halogen, exchange the halogen with the anion in the compound.

-Example with a halogen: Given, “__ Cl2 + ___ AlBr3”

Step 1: Since Cl2 is a halogen, exchange it with Br. Since all of the halogens are diatomic molecules, and since each halogen ion is 1-, the new formulas will be similar to those of the reactants. “( Br2 + AlCl3”

Step 2: Balance the entire equation: 3 Cl2 + 2 AlBr3 ( 3 Br2 + 2 AlCl3

Practice:

______ F2 + _____ AlCl3 ( _______________ + ____________________

_____ Cl2 + _____BaBr2 ( _______________ + ____________________

_____ Br2 + _____NaI (_______________ + ____________________

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Δ

________________

F2, Cl2, Br2, I2, N2, O2, H2

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