Fun With Predicting Reaction Products

By Anne Spencer,2014-05-29 22:13
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Fun With Predicting Reaction Products

    Fun With Predicting Reaction Products

Predict the products of each of the following chemical reactions. If a reaction will

    not occur, explain why not:

1) ____ AgSO + ____ NaNO ; 243

2) ____ NaI + ____ CaSO ; 4

3) ____ HNO + ____ Ca(OH) ; 32

4) ____ CaCO ; 3

5) ____ AlCl + ____ (NH)PO ; 344

6) ____ Pb + ____ Fe(NO) ; 33

7) ____ CH + ____ O ; 362

8) ____ Na + ____ CaSO ; 4

Fun With Predicting Reaction Products Answers

    Predict the products of each of the following chemical reactions. If a reaction will not occur, explain why not:

    Before moving on, here are some general rules of thumb for how to figure out what will be made (and if the reaction will occur at all):

1) If something that has carbon and hydrogen reacts with oxygen, it’s

    probably a combustion reaction. The products will be CO and HO. 22

    2) If two elements or very simple molecules combine with each other,

    it’s probably a synthesis reaction. The products will probably be

    predictable using the octet rule to find charges.

    3) If one compound has an arrow coming off of it, it’s probably a

    decomposition reaction. The products will either be a couple of very

    simple molecules, or some elements, or both.

    4) If a pure element reacts with another compound (usually, but not

    always, ionic), it’s probably a single displacement reaction. The

    products will be the compounds formed when the pure element

    switches places with another element in the other compound.

    ; Important note: these reactions will only occur if the pure element on the

    reactant side of the equation is higher on the activity series than the

    element it replaces.

5) If two ionic compounds combine, it’s probably a double

    displacement reaction. Switch the cations and balance out the

    charges to figure out what will be made.

    ; Important note: These reactions will only occur if both reactants are

    soluble in water and only one product is soluble in water.

6) If an acid and a base combine, it’s an acid-base reaction. The

    products will be an ionic compound and water.

    On the next page are explanations of how this works in sample problems:

1) ____ AgSO + ____ NaNO ; no reaction! 243

    Examining this reaction, it appears that a double displacement reaction will occur. This would lead to the conclusion that the products would be AgNO and NaSO. However, for this reaction to occur, both reactants and 324

    only one of the products must be soluble in water. If you look up the solubilities on a chart, you’ll find that AgSO is partly soluble in water, and 23

    all of the other compounds are totally soluble in water. This tells us that this reaction will not occur.

2) ____ NaI + ____ CaSO ; no reaction! 4

Another double displacement reaction, this time with NaSO and CaI as 242

    products. Because both products are soluble in water and CaSO is only 4

    partially soluble in water, the conditions for a successful double displacement reaction are not met.

3) 2 HNO + 1 Ca(OH) ; 1 Ca(NO) + 2 HO 32322

    It’s an acid-base reaction, and acid-base reactions occur readily whether or not the reactants are both soluble in water.

4) 1 CaCO ; 1 CaO + 1 CO 32

    It’s a decomposition reaction. If you didn’t guess that these were the products, you should have at least known that it was a decomposition reaction and predicted that this would have broken into its constituent elements, Ca, C, and O. 2

5) 1 AlCl + 1 (NH)PO ; AlPO + 3 NHCl3(aq)434(aq)4(s)4(aq)

    This is a double displacement reaction, except in this case both of the reactants and only one product are soluble in water. Because the conditions for a successful reaction are met, the reaction does occur!

6) ____ Pb + ____ Fe(NO) ; no reaction! 33

    Though this is a single displacement reaction, lead is lower on the activity series than the iron it would replace. As a result, this reaction does not occur.

7) 2 CH + 9 O ; 6 CO + 6 HO 36222

    The reactants suggest that this is a combustion reaction, meaning that the products must be carbon dioxide and water. Once you figure this out, the only thing left to do is balance it, as shown.

8) 2 Na + 1 CaSO ; 1 NaSO + 1 Ca 424

    This should clearly be a single displacement reaction. Because sodium is higher on the activity series than calcium, this reaction does occur.

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