Question

12. How many grams are equal to 3.46 moles of sodium sulfide, Na2S?​ with work please

Answer 1

Answer:

$\boxed {\boxed {\sf About \ 270 \ grams \ of \ Na_2 S}}$

Explanation:

To convert from moles to grams, the molar mass must be used.

1. Find Molar Mass

The compound is sodium sulfide: Na₂S

First, find the molar masses of the individual elements in the compound: sodium (Na) and sulfur (S).

• Na:  22.9897693 g/mol
• S:  32.07 g/mol

There are 2 atoms of sodium, denoted by the subscript after Na. Multiply the molar mass of sodium by 2 and add sulfur's molar mass.

• Na₂S: 2(22.9897693 g/mol)+(32.07 g/mol)=78.0495386 g/mol

This number tells us the grams of sodium sulfide in 1 mole.

2. Calculate Grams

Use the number as a ratio.

$\frac{78.0495386 \ g \ Na_2S}{1 \ mol \ Na_2S}$

Multiply by the given number of moles, 3.46.

$3.46 \ mol \ Na_2S *\frac{78.0495386 \ g \ Na_2S}{1 \ mol \ Na_2S}$

The moles of sodium sulfide will cancel.

$3.46 *\frac{78.0495386 \ g \ Na_2S}{1 }$

$3.46 *{78.0495386 \ g \ Na_2S}$

$270.051404 \ g \ Na_2 S$

3. Round

The original measurement of grams, 3.46, has 3 significant figures. We must round our answer to 3 sig figs.

For the answer we calculated, that is the ones place.

The 0 in the tenth place tells us to leave the 0 in the ones place.

$\approx 270 \ g \ Na_2 S$

There are about 270 grams of sodium sulfide in 3.46 moles.

Answer 2

Answer:

Mass = 269.8 g

Explanation:

Given data:

Number of moles of Na₂S = 3.46 mol

Mass of Na₂S = ?

Solution:

Formula:

Mass = number of moles × molar mass

Molar mass of Na₂S = 78.0 g/mol

Mass = 3.46 mol × 78.0 g/mol

Mass = 269.8 g