The vapor pressure of carbon disulfide is 355.6 torr at 25°C. What is the vapor pressure of a solution prepared by dissolving 10.60 g naphthalene (C10H8, Molar Mass = 128.2 g/mol) in 155 mL CS2 liquid (Molar Mass = 76.14 g/mol, density = 1.261 g/mL)? Assume the solution obeys Raoult's law, and treat naphthalene as a nonvolatile solute.
Answers
The vapor pressure of the solution would be as follows:
torr
Given that,
Vapor pressure of Carbon Disulfide torr
Naphthalene's mass
Naphthalene's molar mass
Now,
We know that
Number of moles
Mass ×
×
So,
Number of moles of Carbon Disulfide ×
moles of Carbon Disulfide
Number of moles of Naphthalene:
Number of moles
Now,
Total number of moles :
moles
Mole fraction of each compound in solution :
Carbon Disulfide:
2.567 / 2.65
Naphthalene
0.083 / 2.65
According to Raoult's:
P ×
Carbon Sulfide = Solvent
Mole fraction of solvent
Vapour pressure of the pure solvent
×
torr
Thus, " torr" is the correct answer.
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Answer:
344.5764 torr
Explanation:
Molar mass of naphthalene = 128.2g/mol
Mass of naphthalene = 10.60 g
Carbon disulfide:
Molar mass= 76.14g/mol ;
volume = 155mL ;
density = 1.261 g/mL
Vapour pressure = 355.6 torr
Number of moles = mass / molar mass
CS2:
Mass = density × volume
Number of moles = (density × volume) / molar mass
Number of moles = (1.261 * 155) / 76.14 = (195.455 / 76.14) = 2.567 moles of CS2
Number of moles of C8H10:
Number of moles = 10.60 / 128.2 = 0.083 C8H10
Total number of moles :
2.567 + 0.083 = 2.65 moles
Mole fraction of each compound in solution :
CS2 :
2.567 / 2.65 = 0.969
C8H10:
0.083 / 2.65 = 0.031
According to Raoult's:
Psolution = Xsolvent × Posolvent
CS2 = solvent
Xsolvent = Mole fraction of solvent
Posolvent = Vapour pressure of pure solvent
Psolution = 0.969 × 355.6 torr = 344.5764 torr
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Answers
9.03*10^23 molecules
Final answer:
The number of water molecules in a 1.50 mol block of ice is calculated by multiplying the number of moles of water by Avogadro's number. The result is approximately 9.033 x 10^23 water molecules.
Explanation:
In chemistry, the amount of substance in moles is related to the number of particles (atoms, molecules) through Avogadro's number. Avogadro's number, which is 6.022 x 1023 particles/mol, tells us the number of molecules in one mole of a substance.
To calculate the number of water molecules in 1.50 mol of water, you would multiply the number of moles of water by Avogadro's number:
1.50 mol of water x 6.022 x 1023 water molecules/mol of water = 9.033 x 1023 water molecules
Therefore, there are approximately 9.033 x 1023 water molecules in a 1.50 mol block of ice.
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Answers
Answer:
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Exercise helps cancer survivors cope with and recover from treatment; exercise may improve the health of long term cancer survivors and extend survival. Physical exercise will benefit throughout the spectrum of cancer. However, an understanding of the amount, type and intensity of exercise needed has not been fully elucidated. There is sufficient evidence to promote exercise in cancer survivors following careful assessment and tailoring on exercise prescription.
"The field of oncology will benefit from understanding the importance of physical activity both for primary prevention as well as in helping cancer survivors cope with and recover from treatments, improve the health of long term cancer survivors and possibly even reduce the risk of recurrence and extend survival after a cancer diagnosis" (P. Rajarajeswaran, R. Vishnupriya)
Additional studies will be needed to more firmly establish physical activity benefits to cancer survivors.
- R. Segal, MD*, C. Zwaal, MSc†, E. Green, RN‡, J.R. Tomasone, PhD§, A. Loblaw, MD MSc‖, T. Petrella, MD, Exercise for people with cancer: a clinical practice guideline. 2017. Canadian Cancer Research Journal.
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- Efficacy of exercise interventions in patients with advanced cancer: A systematic review. Archives of Physical Medicine and Rehabilitation, May 2018.
- McNeely ML. Exercise as a promising intervention in head & neck cancer patients. Indian J Med Res.
- P. Rajarajeswaran, R. Vishnupriya. Exercise in cancer. College of Physiotherapy, Mother Theresa Post Graduate and Research Institute of Health Sciences, India.
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It is scientifically proven that properly prescribed physical exercise can be performed without risk during and after chemotherapy and radiotherapy treatments. However, it is necessary to adjust its intensity, duration, weekly frequency and type of exercise to the general condition of the patient. Physical exercise will improve the quality of life, fatigue and mood of the cancer patient being treated. It will also improve the prognosis of the disease, its quality of future life and its final life expectancy.
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Answers
Answer : The mass of sucrose added to 375 mL of water must be, 10.6 grams.
Explanation :
As we are given that 2.75 m/m percent solution of sucrose. That means, 2.75 grams of sucrose present in 100 grams of solution.
Mass of solution = 100 g
Mass of sucrose = 2.75 g
Mass of water = Mass of solution - Mass of sucrose
Mass of water = 100 g - 2.75 g
Mass of water = 97.25 g
First we have to calculate the mass of water.
Density of water = 1.00 g/mL
Volume of water = 375 mL
Now we have to calculate the mass of sucrose in 375 g of water.
As, 97.25 grams of water contain 2.75 grams of sucrose
So, 375 grams of water contain grams of sucrose
Therefore, the mass of sucrose added to 375 mL of water must be, 10.6 grams.
To make a 2.75% m/m sucrose solution, you need to add approximately 1062 grams of sucrose to 375 mL of water, considering the density of water as 1 g/mL.
To prepare a mass/mass (m/m) percent solution of sucrose, you need to calculate the mass of sucrose (in grams) that needs to be added to 375 mL of water to achieve a 2.75% concentration.
Here's how you can calculate it:
1. Convert the volume of water to grams, considering the density of water:
Density of water ≈ 1 g/mL
Mass of water = Volume of water × Density of water
Mass of water = 375 mL × 1 g/mL = 375 g
2. Determine the desired mass of sucrose as a percentage of the total mass:
Desired m/m percent = 2.75%
3. Calculate the mass of sucrose needed:
Mass of sucrose = (Desired m/m percent / 100) × Total mass
Mass of sucrose = (2.75 / 100) × (375 g + Mass of sucrose)
4. Rearrange the equation to solve for the mass of sucrose:
Mass of sucrose = (2.75 / 100) × (375 g) / (1 - (2.75 / 100))
Now, calculate:
Mass of sucrose = (2.75 / 100) × (375 g) / (1 - 0.0275)
Mass of sucrose ≈ (2.75 / 100) × (375 g) / 0.9725
Mass of sucrose ≈ (2.75 × 375 g) / 100 / 0.9725
Mass of sucrose ≈ (1031.25 g) / 0.9725
Mass of sucrose ≈ 1061.98 g
So, approximately 1062 grams of sucrose must be added to 375 mL of water to prepare a 2.75 m/m percent solution of sucrose.
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other and takes the shape of a container, filling it from the bottom up? (3 points)
1) Gas
2) Liquid
3) Plasma
4) Solid
Answers
Answers
61.8 % is the mass percentage of magnesium sulphate.
Explanation:
The mass percent of individual solute or ion in a compound is calculated by the formula:
Grams of solute ÷ grams of solute + solvent × 100
mass percent of magnesium is calculated as 1 mole of magnesium having 24.305 grams/mole will have weight of 24.305 grams and 1 mole of MgSO4 will have 120.366 grams
Putting the values in the equation:
24.305 ÷ 144.671 × 100
= 16.8% of magnesium is in the mixture
The mass percentage of SO4 is calculated as
= 96.06 ÷ 216.426 × 100
= 44.38 %
The mass percentage of the mixture MgSO4 is 44.38 + 16.8 = 61.8 %
Mass percentage is a representation of the concentration of element or elements in a compound.