1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Semenov [28]
3 years ago
6

It has been suggested that the surface melting of ice plays a role in enabling speed skaters to achieve peak performance. Carry

out the following calculation to test this hypothesis. At 1 atm pressure, ice melts at 273.15 K (delta)Hfusion= 6010J/mol, the density of ice is 920 kg/m3, and the density of liquid water is 997 kg/m3.
Part A:
What pressure is required to lower the melting temperature by 4.7 degrees Celsius?
Part B:
Assume that the width of the skate in contact with the ice has been reduced by sharpening to 0.019 cm, and that the length of the contact area is 18 cm. If a skater of mass 79kg is balanced on one skate, what pressure is exerted at the interface of the skate and the ice?
Part C:
What is the melting point of ice under this pressure?
Chemistry
1 answer:
Fittoniya [83]3 years ago
4 0

Answer:

a) Pf = 689.4 bar

b) P = 226.6 bar

c) T = 269.99 K

Explanation:

a)

The molar volume of ice is equal to:

Vi = m/p = (18.02x10^-3 kg H2O/1 mol H2O)*(1 m^3/920 kg) = 1.96x10^-5 m^3 mol^-1

The molar volume of liquid water is equal to:

Vl = (18.02x10^-3 kg/1 mol)*(1 m^3/997 kg) = 1.8x10^-5 m^3 mol^-1

The change in volume is equal to:

ΔVchange = Vi-Vl = 1.96x10^-5 - 1.8x10^-5 = 1.5x10^-6 m^3 mol^-1

using the Clapeyron equation:

Pf = Pi + ((ΔHf*ΔT)/(ΔVf*Ti)) = 1.013x10^5 Pa + ((6010 J mol^-1 * 4.7 K)/(1.5x10^-6 * 273.15 K)) = 6.89x10^7 Pa = 689.4 bar

b)

For the pressure we will use the equation:

P = (m*g)/A, where m is the mass, g is the acceleration of gravity and A is the area. Replacing values:

P = (79 kg * 9.81 m s^-2)/(1.9x10^-4 m * 0.18 m) = 2.26x10^7 Pa = 226.6 bar

c)

From Clapeyron´s expression we need to clear ΔT:

ΔT = ((Pf-Pi)*ΔV*Ti)/ΔHf = ((2.26x10^7 - 6.89x10^7)*1.5x10^-6*273.15)/6010 = -3.16 K

you can evaluate the new melting point of ice:

T = Ti + ΔT = 273.15 K - 3.16 K = 269.99 K

You might be interested in
Elements that are generally shiny when smooth and clean.
Verdich [7]
Metals are elements that are generally shiny when smooth and clean
5 0
3 years ago
What subatomic particles are most involved in chemical bonding?
MAVERICK [17]
D. Electrons
Atoms can share their electrons in order to create bonds with other atoms
8 0
4 years ago
Read 2 more answers
Specify the number of protons, neutrons, and electrons in the neutral atom iron-56. Enter your answers as integers separated by
I am Lyosha [343]

Answer:idk

Explanation:

4 0
3 years ago
Read 2 more answers
What is a way in which nuclear fusion is used?
Marta_Voda [28]

Answer:It is a nuclear process, where energy is produced by smashing together light atoms. It is the opposite reaction of fission, where heavy isotopes are split apart.

Explanation Fusion is the process by which the sun and other stars generate light and heat.

It’s most easily achieved on Earth by combining two isotopes of hydrogen: deuterium and tritium. Hydrogen is the lightest of all the elements, being made up of a single proton and a electron. Deuterium has an extra neutron in its nucleus; it can replace one of the hydrogen atoms in H20 to make what is called “heavy water.”

3 0
3 years ago
Find the natural abundance of Si-30.
nataly862011 [7]
<span> First you need to know how many isotopes there are of silicon, and its average atomic units (look at periodic table). Then make up a system of equations to solve for it. Theres 3 stable silicon isotopes (28, 29, 30) so you will need to have 3 equations. You must be given the percent abundance of at least one of the isotopes to solve because here I can only see 2 equations (numbered down below) set x = percent abundance of si-28 y = percent abundance of si-29 z = percent abundance of si-30 since all of silicon atoms account for 100% of all silicon: x + y + z = 100% = 1 therefore: 1) x = 1 - y - z You also have 2) 28x + 29y + 30z = average atomic mass you can substitute x so that equation becomes: 28 (1 - y - z) + 29y + 30z = average atomic mass See how you have 2 variables here? You cant go on until you know the value of one isotope already or you have given a clue which you can derive the third equation</span>
5 0
3 years ago
Other questions:
  • You are given two unknown solutions, A and B. One of the solutions contains water and table salt, and the other contains water a
    12·2 answers
  • Can someone please help me with this question? I don't understand it
    9·2 answers
  • What is the mass in grams of the Hope Diamond, the world's largest blue diamond at 44.4 carats?
    5·1 answer
  • A lithium atom that has lost an electron comes near a chlorine atom that has gained an electron. What happens?
    14·2 answers
  • Hydrochloric acid and sodium hydroxide will produce which two compounds
    8·1 answer
  • Below is a list of molecules with different chemical characteristics. Knowing that all molecules will eventually diffuse across
    12·1 answer
  • An aqueous solution has a normal boiling point of 103.0°
    8·1 answer
  • What is NOT a sign of chemical change?
    8·1 answer
  • In P plants the gene for the color of the sea has two alleys in the punnets square show me love the dominant alley Y represents
    12·1 answer
  • A 4.16L balloon filled with gas is warmed from 251.5K to 298.4 K. What is the volume of the gas after it is heated?
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!