Question

TÍNH THEO CTHH

Tình % khối lượng các nguyên tố có trong các hợp chất sau;

a. MgCO3

b. NaCl

Answer 1

\(a.\)

\(M_{MgCO_3}=84\left(\dfrac{g}{mol}\right)\)

\(\%Mg=\dfrac{24}{84}\cdot100\%=28.57\%\)

\(\%C=\dfrac{12}{84}\cdot100\%=14.28\%\)

\(\%O=100-28.57-14.28=57.15\%\)

\(b.\)

\(M_{NaCl}=58.5\left(\dfrac{g}{mol}\right)\)

\(\%Na=\dfrac{23}{58.5}\cdot100\%=39.31\%\)

\(\%Cl=\dfrac{35.5}{58.5}\cdot100\%=60.69\%\)

Answer 2

\(a,M_{MgCO_3}=84(g/mol)\\ \begin{cases} \%_{Mg}=\dfrac{24}{84}.100\%=28,57\%\\ \%_{C}=\dfrac{12}{84}.100\%=14,29\%\\ \%_{O}=100\%-28,57\%-14,29\%=57,14\% \end{cases}\)

\(a,M_{NaCl}=58,5(g/mol)\\ \begin{cases} \%_{Na}=\dfrac{23}{58,5}.100\%=39,32\%\\ \%_{C}=100\%-39,32\%=60,68\% \end{cases}\)