A phylogenetic tree may be built using morphological (body shape), biochemical, behavioral, or molecular features of species or other groups. In building a tree, we organize species into nested groups based on shared derived traits (traits different from those of the group's ancestor).
In a typical double displacement reaction, you would have a total of two products (AB + CD —> AD + BC).
Ba stays as Ba+2 and Cl stays as Cl-
Let's go through each of the answers and think about why they work or don't work.
Chemical forms compounds.
Nuclear changes the element completely. We're going to use the sun as an example. The sun is in a state of plasma. It's really hot and has all these particles hitting into each other. The nucleus' of atoms are hitting into each other forming larger elements. It's real crazy. Nuclear is not correct.
Physical cannot form a compound.
Answer:
a) 2NaOH(aq) + CuSO4(aq) -------------> Cu(OH)2(s) + Na2SO4(aq)
b) Ca(OH)2(aq) + CO2(g) --------------> CaCO3 + H2O (this is already balanced)
c) Pb(NO3)2 + H2SO4 --------> PbSO4 + 2HNO3.
d) 2KNO3 ------> 2KNO2 + O2
e) H2SO4 + 2(NaOH) -----> Na2SO4 + 2(H2O)
f) Ca(NO3)2(aq) + (NH4)2CO3(aq) ----------------> CaCO3(s) + 2NH4NO3(aq)