I was supposed to figure out whether the following equations produced precipitates or not. Here are my answers, but I know that they are wrong. So I still can't figure out where I'm messing up...? Please help!
HgCl2 (aq) + K2CrO4 (aq) = Yes
Ba(OH)2 (aq) + NaClO3 (aq) = No
ZnI2 (aq) + CaSO4 (aq) = No
SnCl2 (aq) + MgBr2 (aq) = Yes
1 is ok.
2 is ok.
3 is ok.
4 should be no. Of the possible combinations, SnBr2 is soluble as is MgCl2. Did you use the chart I posted for you? It doesn't list mercury(II) chromate but questions 1, 2, and 3 are covered by the table. To be honest about it I can't find the mercury chromate info anywhere; however, mercury(II) dichromate is highly insoluble and my best educated guess is that mercury(II) chromate is insoluble as well. So you're batting 3 out of 4 which isn't bad at all.
Great, thanks! :)
To determine whether a precipitate is formed in a chemical reaction, you need to consider the solubility rules. These rules predict which combinations of ions will produce insoluble (precipitated) compounds.
Let's go through each equation and check the solubility rules.
1. HgCl2(aq) + K2CrO4(aq) = ???
To determine if a precipitate is formed, we need to see if there is an insoluble compound formed when the two ionic compounds react. According to the solubility rules:
- Mercury(II) chloride (HgCl2) is soluble in water.
- Potassium chromate (K2CrO4) is also soluble in water.
Since both compounds are soluble, no precipitate is formed.
Therefore, the correct answer for this equation is No, there is no precipitate.
2. Ba(OH)2(aq) + NaClO3(aq) = ???
Let's check the solubility rules:
- Barium hydroxide (Ba(OH)2) is soluble, except when combined with Group 2A elements (such as calcium, strontium, and barium).
- Sodium chlorate (NaClO3) is soluble in water.
Since Ba(OH)2 is soluble, we need to check if it forms an insoluble compound with sodium chlorate. According to the solubility rules, chlorates (ClO3-) are generally soluble.
Therefore, the correct answer for this equation is No, there is no precipitate.
3. ZnI2(aq) + CaSO4(aq) = ???
Let's check the solubility rules:
- Zinc iodide (ZnI2) is soluble in water.
- Calcium sulfate (CaSO4) is slightly soluble, but forms an insoluble compound with many cations, including zinc.
Since the combination of ZnI2 and CaSO4 forms an insoluble compound (calcium iodide, CaI2), a precipitate is formed.
Therefore, the correct answer for this equation is Yes, a precipitate is formed.
4. SnCl2(aq) + MgBr2(aq) = ???
Let's check the solubility rules:
- Tin(II) chloride (SnCl2) is soluble in water.
- Magnesium bromide (MgBr2) is also soluble in water.
Since both compounds are soluble, no precipitate is formed.
Therefore, the correct answer for this equation is No, there is no precipitate.
I hope this helps you identify where you went wrong. Remember to use the solubility rules to determine the solubility of specific compounds in water and predict whether a precipitate will form.