New set of equations (related to my last post - by accident)

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Thanks for your replies.Seeing that we have two lab reports due the same day, and the second one being the same subject, I won't be able to ask my teacher beforehand. So I have four more equations that need finding the product of. Zedekiah, I have a table named "Solubility of Common Compounds in Water", which allows me to see which chemicals would react and form a precipitate and which ones wouldn't. I also have the knowledge to balance an equation, so maybe if you could shortly (if technically possible) describe just how to find the product without balancing the equation (if it can be done that way) ? If it's a complicated process, I will ask my teacher about it, and maybe get a chance to hand it in later.

Here is my list of equations that the product need to be found of =
- H₂₀ + NaSO₄ = ?
- Mg + NaOH = ?
- Ca + NaSO₄ = ?
- NaCO₃ + Ca = ?

Thanks for all your help so far!

[Zedekiah]

Okay, a crash course on predicting products.

There are five basic types of reactions.



1) Combustion. This is almost invariably a hydrocarbon + oxygen forming water and CO₂.
Whenever you see, for example, a compound that has carbon, hydrogen and/or oxygen reacting with O₂, you have a combustion reaction.
The product is going to be water and CO₂.

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C2H6 + O2  --> ?

Since this is clearly a hydrocarbon + oxygen, the products are CO₂ and H₂O. Then balance and you're done.




2) Synthesis. Synthesis usually involves two elements combining to form another. This is also quite easy to recognize.

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H2 +  O2  -->  ?

Since there are only two things, assume they combine.

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H2 + O2 -->  H2O  

All you have to do now is balance.



3) Decomposition. This type of reaction involves one compound becoming two or more. These are more difficult to predict, but they usually involve heating the compound. As an example :

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KClO3  --heat-->   ?

In this case, you basically have to know the products.

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2KClO3  --heat-->   2KCl   +  3O2

But they're usually pretty easy to pick out of a crowd.





4) Single replacement. This involves one element replacing another in an ionic salt. For this type of problem, you will need an activity series of metals. Higher elements, when alone, will replace lower elements that are in salts.

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Mg +  AgNO3 --> ?

Look up the activity series. You will find magnesium is much higher on the list than silver. Therefore, the magnesium will replace the silver.

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Mg  +  2AgNO3  -->   Mg(NO3)2  + 2Ag

5) Double replacement. All of the reactions you have posted are double replacement (except for the first). These occur when you mix two solutions and a precipitate forms. You know if a precipitate forms by checking the solubility on your solubility chart of all of the products.

Example : When you mix a solution of magnesium sulfate and sodium hydroxide. First, write the products by switching the ions. EG : if it is magnesium sulfate and sodium hydroxide, write sodium sulfate and magnesium hydroxide.

MgSO₄ + 2NaOH ---> Na₂SO₄ + Mg(OH)₂

To find out if a reaction occurs, check to see if the products are soluble.

According to your rules, sodium sulfate is soluble. This means that it will not precipitate. Checking magnesium hydroxide reveals that it is not soluble! This means that a reaction occurs, a double replacement reaction.



So, solving the problems you've posted :


H₂O + Na₂SO₄ --> 2Na(+) + SO₄(2-)

This is just something dissolving in water.


Check the solubilities of the products that could form here.
Mg(2+) + 2NaOH --> 2Na(+) + Mg(OH)₂
Magnesium hydroxide is insoluble, so this reaction occurs.


Ca(2+) + Na₂SO₄ --> CaSO₄ + 2Na(+)

Calcium sulfate, again, is insoluble so it precipitates.


Ca(2+) + Na₂CO₃ --> CaCO₃ + 2Na(+)

Calcium carbonate is insoluble so it precipitates.


Hope that helped, if you have any questions, just ask .

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Yep that helped! I also e-mailed my teacher, so now I know exactly what to do.

This will be it for now

Thanks for all your help!