What is the number of moles of Na\(_H\)CO\(_3\) in 250cm\(^3\) of its solution if the solution contains 8.4 g of Na\(_H\)CO\(_3\) in 1 dm\(^3\) of the solution. [Na = 23, 0 = 16, C = 12, H = 1)

Ekeledilichukuwu

4 years ago

m=mass/molar mass
M=8.4/84
M=0.1 g/mol
X = 250/1000×0.1
-------------------------
1000
Cancel out 1000
250×0.1
=0.025mol

profizunduGodwin

5 years ago

I'm getting 0.4 as the answer ...
how is it 0.025 ??

Ayomiart

2 years ago

No provided answer to the question

JohnProjectile

1 year ago

To find the number of moles of NaHCO3, we need to follow these steps:

1. Calculate the molar mass of NaHCO3:
Na = 23, H = 1, C = 12, O = 16 (x3) = 48
Molar mass = 23 + 1 + 12 + 48 = 84 g/mol

2. Calculate the concentration of NaHCO3 in moles per liter (mol/L):
8.4 g NaHCO3 / 1 dm3 (1000 cm3) = 0.084 g/cm3
Moles/L = 0.084 g/cm3 / 84 g/mol = 0.001 mol/cm3

3. Calculate the number of moles in 250 cm3:
Moles = concentration x volume = 0.001 mol/cm3 x 250 cm3 = 0.25 mol

The correct answer is B: 0.25

ugolove

10 years ago

I keep getting 0.4 as MA ans, can someone brief me on hw d ans is 0.025 pls