How many moles are in 4.24kg of Na2CO3? Hint : You need to convert from kg to grams first A. 4.00 x 10 -2 moles B. 40.0 moles C. 4.49 x 105 moles D. 2.55 x 1028 moles

Question

asked Jan 10, 2018 24.7k views

1 Answer

Hsluoyz · Answer 1 · 2018-01-16T21:46:37+0000

Data:
4.24 Kg converting (grams) → 4240 g

Molar Mass of
Na_(2) CO_(3)

Na = 2*23 = 46 amu
C = 1*12 = 12 amu
O = 3*16 = 48 amu
-------------------------
Molar Mass of
Na_(2) CO_(3)

= 46 + 12 + 48 = 106 g/mol

If:

106 g → 1 mol
4240 g → y

Solving: Rule of three (directly proportional)

(106)/(4240) = (1)/(y)

multiply cross
106*y = 4240*1
106y = 4240

y = (4240)/(106)

$\boxed{\boxed{y = 40\:moles}}\end{array}}\qquad\quad\checkmark$

Answer:
B. 40.0 moles