The boiling point of an aqueous 1.83 m (nh4)2so4 (molar mass = 132.15 g/mol) solution is 102.5°c. determine the value of the van't hoff factor for this solute if the kb for water is 0.512°c/m. 2.7 1.8 2.3 3.0 3.6

Chromatography is a pretty accurate description of what happens to ink on wet paper, because it literally means "color writing" (from the Greek words chroma and graphe). Really, though, it's a bit of a misnomer because it often doesn't involve color, paper, ink, or writing. Chromatography is actually a way of separating out a mixture of chemicals, which are in gas or liquid form, by letting them creep slowly past another substance, which is typically a liquid or solid. So, with the ink and paper trick for example, we have a liquid (the ink) dissolved in water or another solvent creeping over the surface of a solid (the paper).

The essential thing about chromatography is that we have some mixture in one state of matter (something like a gas or liquid) moving over the surface of something else in another state of matter (a liquid or solid) that stays where it is. The moving substance is called the mobile phase and the substance that stays put is the stationary phase. As the mobile phase moves, it separates out into its components on the stationary phase. We can then identify them one by one.

Answer:

11.39

Explanation:

Given that:

Given that:

Mass = 1.805 g

Molar mass = 82.0343 g/mol

The formula for the calculation of moles is shown below:

Thus,

Given Volume = 55 mL = 0.055 L ( 1 mL = 0.001 L)

Concentration = 0.4 M

Consider the ICE take for the dissociation of the base as:

                                  B +   H₂O    ⇄     BH⁺ +        OH⁻

At t=0                        0.4                          -              -

At t =equilibrium     (0.4-x)                        x           x            

The expression for dissociation constant is:

x is very small, so (0.4 - x) ≅ 0.4

Solving for x, we get:

x = 2.4606×10⁻³  M

pOH = -log[OH⁻] = -log(2.4606×10⁻³) = 2.61

pH = 14 - pOH = 14 - 2.61 = 11.39

Answer: C. Electrons give off electromagnetic radiation when they jump from a high to a low energy level.

Explanation:

 Electrons give off electromagnetic radiation when they jump from a high to a low energy level in the quantum mechanical atomic model. This is known as the emission spectrum of an atom, and each element has its unique emission spectrum. This phenomenon was explained by the Bohr model of the atom and is a fundamental concept of the quantum mechanical atomic model.

 Option A is incorrect because atoms cannot absorb or emit electrons from the nucleus when they interact with electromagnetic radiation. Option B is also incorrect because atoms only absorb certain wavelengths of light energy or electromagnetic radiation, which corresponds to the energy difference between electron energy levels. Option D is incorrect because electrons are not evenly distributed throughout the atom in the quantum mechanical atomic model; instead, they occupy specific energy levels or orbitals.

Answer:

Please refer to the attachment below.

Explanation:

Please refer to the attachment below for explanation.

Answer:

ksp = 0,176

Explanation:

The borax (Na₂borate) in water is in equilibrium, thus:

Na₂borate(s) ⇄ borate²⁻(aq) + 2Na⁺(aq)

When you add just borax, the moles of Na²⁺ are twice the moles of borate²⁻, that means 2borate²⁻=Na⁺ (1)

The ksp is defined as:

ksp = [borate²⁻] [Na⁺]²

Then, borate²⁻(B₄O₇²⁻) reacts with HCl thus:

B₄O₇²⁻ + 2HCl + 5H₂O → 4H₃BO₃ + 2Cl⁻

The moles of HCl that reacts with B₄O₇²⁻ are:

0,500M×0,01200L = 6,00x10⁻³ mol of HCl

As two moles of HCl react with 1 mol of B₄O₇²⁻, the moles of B₄O₇²⁻ are:

6,00x10⁻³ mol of HCl× = 3,00x10⁻³ mol of B₄O₇²⁻

For (1), moles of Na⁺ are 3,00x10⁻³ mol ×2 = 6,00x10⁻³ mol of Na⁺

The [borate²⁻] is 3,00x10⁻³ mol of B₄O₇²⁻/0,00850L = 0,353M

And [Na⁺] is 6,00x10⁻³ mol of Na⁺ / 0,00850L = 0,706M

Replacing in the expression of ksp:

ksp = [0,353] [0,706]²

ksp = 0,176

I hope it helps!

The mass of air in room as per given density is 53.2 kg.

To calculate the mass of air contained in a room, we can use the formula:

mass = density x volume

Here, the given density of air is 1.29 g/dm³ at 25°C. We can convert the dimensions of the room to decimeters (dm) by multiplying by 10:

Length = 2.50 m × 10 = 25 dm

Width = 5.50 m × 10 = 55 dm

Height = 3.00 m × 10 = 30 dm

Now, we can calculate the volume of the room by multiplying the three dimensions:

Volume = length x width x height

Volume = 25 dm x 55 dm x 30 dm

Volume = 41,250 dm³

Finally, we can use the formula to calculate the mass of air:

mass = density x volume

mass = 1.29 g/dm³ x 41,250 dm³

mass = 53,212.5 g or 53.2 kg

Therefore, the mass of air contained in the room is approximately 53.2 kg.

Learn more about density,here:

brainly.com/question/29775886

#SPJ3

Explanation:

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