V(H₂O)=500 mL
p(H₂O)=0.9982 g/mL
m(H₂O)=V(H₂O)p(H₂O)
mass of salt solution:
m=m(H₂O)+m(CuSO₄)=V(H₂O)p(H₂O)+m(CuSO₄)
w = m(CuSO₄)/m
w=m(CuSO₄)/{V(H₂O)p(H₂O)+m(CuSO₄)}
w=2.5/{500*0.9982+2.5}=0.004984 (0.4984%)
#2 reactivity is the answer
The answer should be (D) Ca, because all others either occur as diatomic or are anions.
