How do you find predicted products from a chemical reaction?

Question

Like what would the products of KCl and NaOH?

an example my homework gave me was Ba(NO3)2 and K2CO3
(the numbers are subscripts, I don't know how to make those)
the produs wer BaCO3+KNO3

Answer 1

The type of reaction you're dealing with is known as a "double displacement" reaction. These are ionic compounds, so you can think of each of the starting materials as having two parts, a cation (positively-charged ion) and an anion (negatively-charged ion).

For example in the first reaction involving KCl and NaOH, you're really dealing with K+, Cl-, Na+ and OH- (since these reactions occur in water, the compounds ionize). Now you know from magnets that positive (+) attracts negative (-) while poles of the same charge repel each other so they won't come together--a very similar thing happens with these compounds. When you mix these four ions (K+, Cl-, Na+ and OH-), each cation (K+ and Na+) can combine with each anion (Cl- and OH-) to form FOUR possible compounds: KCl, NaOH, KOH, and NaCl. Thus, your products are KOH and NaCl.

In your example, you have Ba(NO3)2 and K2CO3, which means you have the following cations: Ba+2 and K+ and the following anions: (NO3)- and (CO3)-2. Note that Ba and CO3 have charges of positive and negative TWO, respectively. When you combine the cations and anions you get four possible products again: Ba(NO3)2, K2CO3, BaCO3 and KNO3. Remember that the products you form are NOT charged (ie. the icharges of the ions forming them sum up to zero). For example, when you combine Ba+2 and (CO3)-2, you get an overall charge of +2 + (-2) = 0. But when you combine Ba+2 and (NO3)-, you get an overall charge of +2 + (-1) = +1, thus you have to combine it with TWO (NO3)-1 to make it neutral overall.

I hope this helps!

Answer 2

Ba(NO3)2 + K2CO3 => BaCO3(s) + 2KNO3
it is a double displacement , in which two compounds in aqueous solution (usually ionic) exchange elements or ions to form different compounds