Answer:
3.1°C
Explanation:
Using freezing point depression expression:
ΔT = Kf×m×i
<em>Where ΔT is change in freezing point, Kf is freezing point depression constant (5.12°c×m⁻¹), m is molality of the solution and i is Van't Hoff factor constant (1 For I₂ because doesn't dissociate in benzene).</em>
Molality of 9.04g I₂ (Molar mass: 253.8g/mol) in 75.5g of benzene (0.0755kg) is:
9.04g ₓ (1mol / 253.8g) = 0.0356mol I₂ / 0.0755kg = 0.472m
Replacing in freezing point depression formula:
ΔT = 5.12°cm⁻¹×0.472m×1
ΔT = 2.4°C
As freezing point of benzene is 5.5°C, the new freezing point of the solution is:
5.5°C - 2.4°C =
<h3>3.1°C</h3>
<em />
Answer:
The volume that this same amount of air will occupy in his lungs when he reaches a depth of 124 m is - 0.27 L.
Explanation:
Using Boyle's law

Given ,
V₁ = 3.6 L
V₂ = ?
P₁ = 1.0 atm
P₂ = 13.3 atm (From correct source)
Using above equation as:




The volume that this same amount of air will occupy in his lungs when he reaches a depth of 124 m is - 0.27 L.
The definition of pseudoscience is collection of beliefs or practices mistakenly regarded as being based on scientific method. which B is very similar to that. I believe the answer is A.
Have a nice day.
Answer:
As you haven't explained what measurements you took before solving this problem, I will explain the general procedure to evaluate the efficiency of a kettle. I hope it helps you. I´ll send an attachement file with the full answer, since I couldn't write it here.
I assume that the material that is going to be heated in the kettle is water.
1- You have to boil water in it and take the time it takes to its boiling point (in seconds).
2- You have to evaluate the amount of energy the water absorbed Q with the efficiency formula which I explain in the attachement file.
3- Divide Q by the time it took to bring the water to boiling so you can have the power it consumed.
4- You divide the last value you obtained by the Kettles's power rating.
5- Multiply the last value by 100 to obtain a percentage value of efficiency.
Explanation:
Efficiency is the ration of a machine's useful work, in this case how much energy the water absorbed to get to its boiling point divided by the time it took to get to this point, and the total energy expended, in this case the kettles's power rating.
First, we determine the number of moles of barium phosphate. This is done using:
Moles = mass / Mr
Moles = 1 / 602
Moles = 0.002
Now, we see from the formula of the compound that each mole of barium phosphate has 2 moles of phosphorus (P). Therefore, the moles of phosphorus are:
0.002 * 2 = 0.004
The number of particles in one mole of substance is 6.02 x 10²³. The number of phosphorus atoms will be:
0.004 * 6.02 x 10²³
2.41 x 10²¹ atoms of phosphorus are present