Câu 7:

$1,PTK_{Fe_2(SO_4)_x}=56.2+(32+16.4)x=400\\ \Rightarrow 112+96x=400\Rightarrow x=3\\ 2,PTK_{Fe_xO_3}=56x+16.3=160\\ \Rightarrow x=2\\ 3,PTK_{Al_2(SO_4)_x}=27.2+(32+16.4)x=342\\ \Rightarrow 54+96x=342\Rightarrow x=3\\ 4,PTK_{K_2(SO_4)x}=39.2+(32+16.4)x=174\\ \Rightarrow 78+96x=174\Rightarrow x=1\\ 5,PTK_{Ca_x(PO_4)_2}=40x+(31+16.4).2=310\\ \Rightarrow 40x+190=310\Rightarrow x=3$

Câu 8:

$a,d_{CO/N_2}=\dfrac{12+16}{14.2}=1\\ b,d_{CO_2/O_2}=\dfrac{12+16.2}{16.2}=1,375\\ c,d_{N_2/H_2}=\dfrac{14.2}{2.1}=14\\ d,d_{CO_2/N_2}=\dfrac{12+16.2}{14.2}=1,57\\ e,d_{H_2S/H_2}=\dfrac{2+32}{2}=17$

Câu 9:

$a,d_{N_2/kk}=\dfrac{14.2}{29}=0,9655\\ b,d_{CO_2/kk}=\dfrac{12+16.2}{29}=1,52\\ c,d_{CO/kk}=\dfrac{12+16}{29}=0,9655\\ d,d_{C_2H_2/kk}=\dfrac{24+2}{29}=0,8966\\ d_{C_2H_4/kk}=\dfrac{24+4}{29}=0,9655$