Chemistry, 15.07.2019 23:30 connie2168

Ametal oxide with the formula mo contains 15.44% oxygen. in the box below, type the symbol for the element represented by m.

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Answer from: mads3499

The element represented by M is Strontium.

Explanation:

Let us consider the molar mass of metal be 'x'.

The molar mass of MO will be = Molar mass of oxygen + Molar mass of metal = (16 + x)g/mol

It is given in the question that 15.44% of oxygen is present in metal oxide. So, the equation becomes:

$\frac{15.44}{100}\times (x+16)=16g/mol\\\\(x+16)=\frac{16g/mol\times 100}{15.44}\\\\x=(103.626-16)g/mol\\\\x=87.62g/mol$

The metal atom having molar mass as 87.62/mol is Strontium.

Hence, the element represented by M is Strontium.

Answer from: crystaldewar55C

The metal present in the given metal oxide is strontium and its atomic symbol is $\boxed{{\text{Sr}}}$ .

Further explanation:

Mole is the measure of the amount of substance. Mole is the relation between the mass of the substance and molar mass of a substance. It is defined as the mass of a substance in grams divided by its molar mass (g/mol).

The expresion to calculate the number of moles is as follows:

${\text{Number of moles}}\;=\;\dfrac{{{\text{Given mass}}\left( {\text{g}}\right)}}{{{\text{molar mass}}\left({{\text{g/mol}}}\right)}}$ ...... (1)

The given metal oxide MO contains 15.44 % oxygen, it means that 100 g of metal oxide MO contains 15.44 g of oxygen. The amount of metal present in 100 g of metal oxide is,

$\begin{aligned\text{Mass of metal}}\left( {\text{g}} \right)&=\left( {{\text{mass of metal oxide}}} \right)-\left( {{\text{mass of oxygen}}}\right)\\&=100{\text{ g}}-{\text{15}}{\text{.44 g}}\\&={\text{84}}{\text{.66 g}}\\\end{aligned}$

The number of moles of oxygen in 100 g of metal oxide can be calculated by dividing mass of oxygen with molar mass of oxygen.

$\begin{aligned}{\text{Number of moles}}\;&=\;\frac{{{\text{mass}}\left( {\text{g}} \right){\text{ of }}{{\text{O}}_2}}}{{{\text{molar mass}}\left( {{\text{g/mol}}} \right){\text{ of }}{{\text{O}}_2}}}\\&=\frac{{{\text{15}}{\text{.44 g}}}}{{16{\text{ g/mol}}}}\\&=0.965{\text{ mol}}\\\end{aligned}$

According to the molecular formula of metal oxide MO, 1 mole of metal oxide contains 1 mole of oxygen and 1 mole of metal. Therefore, the number of moles of metal present in given metal oxide must be 0.965 moles.

The molar mass of metal can be calculated as follow:

$\begin{aligned}{\text{Molar mass}}\left({{\text{g/mol}}}\right)&= \;\frac{{{\text{mass}}\left( {\text{g}} \right){\text{ of metal}}}}{{{\text{number of moles}}\left( {{\text{mol}}} \right)\;{\text{of metal}}}}\\&=\frac{{84.66{\text{ g}}}}{{0.965{\text{ mol}}}}\\&=87.7\,{\text{g/mol}}\\\end{aligned}$