Question

from your work on the previous screen, you saw that decomposition reactions follow the following general pattern: ab→a + b based on this, which of the reactions below are decomposition reactions? 2alpo4(aq)+3mg(s)→2al(s)+mg3(po4)2(aq)+heat na2co3(s)+heat→na2o(s)+co2(g) 2hgo(s)+heat→2hg(l)+o2(g) 2ni3(s)→n2(g)+3i2(g)+heat bacl2(aq)+na2so4(aq)→baso4(s)+2nacl(aq)+heat

Explanation:

• For the reaction \(2AlPO_4(aq)+3Mg(s)\to2Al(s)+Mg_3(PO_4)_2(aq)+\text{heat}\), it is a single - displacement reaction where \(Mg\) displaces \(Al\) from \(AlPO_4\).
• For the reaction \(Na_2CO_3(s)+\text{heat}\to Na_2O(s)+CO_2(g)\), it follows the pattern \(AB\to A + B\) (\(Na_2CO_3\) decomposes into \(Na_2O\) and \(CO_2\)).
• For the reaction \(2HgO(s)+\text{heat}\to2Hg(l)+O_2(g)\), it follows the pattern \(AB\to A + B\) (\(HgO\) decomposes into \(Hg\) and \(O_2\)).
• For the reaction \(2NI_3(s)\to N_2(g)+3I_2(g)+\text{heat}\), it follows the pattern \(AB\to A + B\) (\(NI_3\) decomposes into \(N_2\) and \(I_2\)).
• For the reaction \(BaCl_2(aq)+Na_2SO_4(aq)\to BaSO_4(s)+2NaCl(aq)+\text{heat}\), it is a double - displacement reaction.

Answer:

• \(Na_2CO_3(s)+\text{heat}\to Na_2O(s)+CO_2(g)\)
• \(2HgO(s)+\text{heat}\to2Hg(l)+O_2(g)\)
• \(2NI_3(s)\to N_2(g)+3I_2(g)+\text{heat}\)