Answer:
2.1 kg of water
Explanation:
Step 1: Given data
- Moles of lithium bromide (solute): 4.3 moles
- Molality of the solution (m): 2.05 m (2.05 mol/kg)
- Mass of water (solvent): ?
Step 2: Calculate the mass of water required
Molality is equal to the moles of solute divided by the kilograms of solvent.
m = moles of solute/kilograms of solvent
kilograms of solvent = moles of solute/m
kilograms of solvent = 4.3 mol /(2.05 mol/kg) = 2.1 kg
<span>a. It melts at 1455oC I know this is correct I need One more</span>
Answer:
The number of moles =

The number of molecules =

Explanation:
Volume of the sphere is given by :

here, r = radius of the sphere


Radius = 3 mm
r = 3 mm
1 mm = 0.01 dm (1 millimeter = 0.001 decimeter)
3 mm = 3 x 0.01 dm = 0.03 dm
r = 0.03 dm
<em>("volume must be in dm^3 , this is the reason radius is changed into dm"</em>
<em>"this is done because 1 dm^3 = 1 liter and concentration is always measured in liters")</em>



(1 L = 1 dm3)
Now, concentration "C"=
The concentration is given by the formula :

This is also written as,

moles
One mole of the substance contain "Na"(= Avogadro number of molecules)
So, "n" mole of substance contain =( n x Na )

Molecules =

molecules