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Sarah06109

Answer:

[tex]\boxed {\boxed {\sf A.\ 1.76 \ mol \ NaNO_3}}[/tex]

Explanation:

To covert from grams to moles, the molar mass is used. This is the mass of 1 mole of a substance. These are located on the Periodic Table. They are the equivalent to the atomic masses, but have different units: grams per mole.

We are given the compound: NaNO₃

Look up the values for each individual element (sodium, nitrogen, and oxygen)

  • Na:  22.989769 g/mol
  • N: 14.007 g/mol
  • O: 15.999 g/mol

Now find the molar mass of the entire compound. Notice that oxygen has a subscript of 3 in the formula, so there are 3 atoms of oxygen per molecule. We must multiply its molar mass by 3 before adding the others.

  • O₃: 15.999*3=47.997 g/mol
  • NaNO₃: 22.989769+14.007+47.997=84.993769 g/mol

Use this value as a ratio.

[tex]\frac {84.993769 \ g \ NaNO_3}{1 \ mol \ NaNO_3}[/tex]

Multiply by the given number of grams: 150

[tex]150 \ g \ NaNO_3*\frac {84.993769 \ g \ NaNO_3}{1 \ mol \ NaNO_3}[/tex]

Flip the ratio so the grams of sodium nitrate cancel.

[tex]150 \ g \ NaNO_3*\frac {1 \ mol \ NaNO_3}{84.993769 \ g \ NaNO_3}[/tex]

[tex]150 *\frac {1 \ mol \ NaNO_3}{84.993769}[/tex]

[tex]\frac {150}{84.993769} \ \ mol \ NaNO_3[/tex]

[tex]1.7648352551 \ mol \ NaNO_3[/tex]

If we round to the nearest hundredth, the 4 in the thousandth place tells us to leave the 6.

[tex]1.76 \ mol \ NaNO_3[/tex]

150 grams of sodium nitrate is approximately 1.76 moles of sodium nitrate. Therefore, choice A is correct.

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