Question

calculate the formula mass of sodium carbonate decahydrate. (PROPER ANSWER). ​

Answer 1

Answer:

286 u

Explanation:

Chemical formula of Sodium Carbonate Decahydrate is:

$CH_{20}Na_{2}O_{13}$

Formula unit mass of Sodium: 23 u

Formula unit mass of Hydrogen: 1 u

Formula unit mass of Carbon: 12 u

Formula unit mass of Oxygen: 16 u

Total formula unit mass of $CH_{20}Na_{2}O_{13}$ = C(1) + H(20) + Na(2) + O(13)

                                                                  =(12 x 1) + (1 x 20) + (23 x 2) + (16 x 13)

                                                                  = 12 + 20 + 46 + 208

                                                                  = 286 u

Answer 2

Answer:The formula mass of sodium carbonate decahydrate,

Na

2

CO

3

⋅

10H

2

O

, is

286 u

.

Explanation:

Calculate formula mass of

Na

2

CO

3

⋅

10

H

2

O

.

Multiply the subscript of each element by its relative atomic mass,

A

r

, on the periodic table. No subscript is understood to be

1

. In the case of

10H

2

O

, you will need to also multiply by the coefficient

10

. I'm going to round the

A

r

for each element to a whole number. Your instructor may want you to use more digits.

(

2

×

23 u Na

)

+

(

1

×

12 u C

)

+

(

3

×

16 u O

)

+

(

10

×

2

×

1 u H

)

+

(

10

×

1

×

16 u O

)

=

286 u Na

2

CO

3

⋅

10

H

2

O

If the molar mass is required, it is numerically equal to the formula mass in g/mole.