Ok to answer this question we firsst need to fin the number of mol of Urea (CH4N2O). to do this we simply :
1 mol of urea =15/60.055 = 0.25mol
therefore 200g of water contain 0.25mol
the next step is to determine the malality of our solution in 200g of water, to do this we say:
200 g = 1Kg/1000g = 0.2kg
therefor 0.25mol/0.2Kg = 1.25mol/kg
and from the equation:
we know that i = 1
we are given Kf
b is the molality that we just calculated
therefore;
the solutions freezing point is -2.325°C
Velocity = 3.61 m/s
<h3>Further explanation</h3>
Given
mass of child = 35 kg
mass of sled = 5 kg
Kinetic energy = 260 J
Required
velocity
Solution
Energy because its motion is expressed as Kinetic energy (KE) which can be formulated as:
KE = 1/2.mv²
mass of object :
= mass child + mass sled
= 35 kg + 5 kg
= 40 kg
Input the value :
v²=KE : 1/2.m
v²= 260 : 1/2.40 kg
v²=13
v=3.61 m/s