## What is the mass of—

(c) 10 moles of sodium sulphite (Na
_{
2
}
SO
_{
3
}
)?

**
Answer
**

We know that,

**
Mass of 1 mole of a substance = Molar mass of that substance
**

(c)
**
10 moles of sodium sulphite (Na
**
**
2
**
**
SO
**
**
3
**
**
)
**

**
Mass of 1 mole Na
**
_{
2
}
**
SO
**
_{
3
}
**
atoms = 2 x Molar mass of Na + 1 x Molar Mass of S + 3 x Molar Mass of O
**

= 2 x 23g + 1 x 32g + 3 x 16g

= 46g + 32g + 48g

=
**
126g
**

**
Mass of 10 moles Na
**
_{
2
}
**
SO
**
_{
3
}
**
atoms = 10 x Molar mass of Na
**
_{
2
}
**
SO
**
_{
3
}

= 10 x 126g

=
**
1260g
**