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3 years ago

Which activity performed by a medical professional is primarily based on an understanding of physics

Chemistry

1 answer:

scoundrel [369]3 years ago

3 0

MRI scanning, CAT scanning, radiotherapy, conventional X-ray imaging, ultrasound scans and ultrasound therapy.

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Define saturated and unsaturated fats

saul85 [17]

Answer:

SATURATED: Saturated fat is a type of fat in which the fatty acid chains have all or predominantly single bonds.

UNSATURATED: Unsaturated fats are loosely packed. They tend to be liquid at room temperature.

There are two main types of unsaturated fat:

Monounsaturated

Polyunsaturated

8 0

3 years ago

The vapor pressure of pure water at 25 °c is 23.8 torr. What is the vapor pressure (torr) of water above a solution prepared by

maxonik [38]

The vapour pressure of the solution is 23.4 torr.

Use Raoult’s Law to calculate the vapour pressure:

p₁ = χ₁p₁°

where

χ₁ = the mole fraction of the solvent

p₁ and p₁° are the vapour pressures of the solution and of the pure solvent

The formula for vapour pressure lowering Δp is

Δp = p₁° - p₁

Δp = p₁° - χ₁p₁° = p₁°(1 – χ₁) = χ₂p₁°

where χ₂ is the mole fraction of the solute.

Step 1. Calculate the mole fraction of glucose

n₂ = 18.0 g glu × (1 moL glu/180.0 g glu) = 0.1000 mol glu

n₁ = 95.0 g H_2O × (1 mol H_2O/18.02 g H_2O) = 5.272 mol H_2O

χ₂ = n₂/(n₁ + n₂) = 0.1000/(0.1000 + 5.272) = 0.1000/5.372 = 0.018 62

Step 2. Calculate the vapour pressure lowering

Δp = χ₂p₁° = 0.018 62 × 23.8 torr = 0.4430 torr

Step 3. Calculate the vapour pressure

p₁ = p₁° - Δp = 23.8 torr – 0.4430 torr = 23.4 torr

3 0

3 years ago

Which of the following has the smallest radius? A. O^2- B. F^- C. Li^- D. Be^2+

nordsb [41]

Answer : The correct option is, (D) $Be^{2+}$

Explanation :

Effective nuclear charge : It is defined as the attraction of the protons present in the nucleus of an atom to the outermost electrons.

For ions, the effective nuclear charge changes than the neutral atom.

There are two types of ions:

Cations: They are formed when an atom looses its valence electrons. They are positive ions.

Anions: They are formed when an atom gain electrons in its outermost shell. They are negative ions.

For positive ions, the removal of electron increases the nuclear charge for an outermost electron because the outermost electrons are more strongly attracted by the nucleus. Thus, the effective nuclear charge increases for cations.

From this we conclude that, the size of the cation is smaller than their neutral atom because it has less number of electrons while its nuclear charge remains the same. So, the nucleus attracts the electron more towards itself and leads to the decrease in size.

For negative ions, the addition of electron decreases the nuclear charge for an outermost electron because the outermost electrons are less strongly attracted by the nucleus. Thus, the effective nuclear charge decreases for anions.

From this we conclude that, the size of the anion is greater than their neutral atom because it has more number of electrons while its nuclear charge remains the same. So, the nucleus attracts the electron less towards itself and leads to the increase in size.

Thus, the increasing order of radius of ions will be:

$Be^{2+}$