Đáp án:
Giải thích các bước giải:
`MK=1,66.`$10^{-24}$.`39 =64,74.`$10^{-23}$ `g`
`MCa=1,66.`$10^{-24}$`.40=6,64.`$10^{-23}$ `g`
`MCr=1,66.`$10^{-24}$`.52=6,64.`$10^{-23}$ `g`
`MS=1,66.`$10^{-24}$`.32=5,312.`$10^{-23}$ `g`
`MFe=1,66.`$10^{-24}$`.56=9,296.`$10^{-23}$ `g`