What information did mendeleev have about the elements he organized into a periodic table

How many distillation are there?

anyanavicka [17]

Answer:

5

Explanation:

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4 0

4 years ago

A holiday ornament in the shape of a hollow sphere with mass 0.015 kg and radius 0.055 m is hung from a tree limb by a small loo

s344n2d4d5 [400]

Answer: 0.61 s

Explanation:

Given

Mass of object, m = 0.015 kg

Radius of object, r = 0.055 m

Acceleration of object, g = 9.8 m/s²

In a pendulum,

T = 2π * √[I /(mgd)]

The moment of Inertia, I of a hollow sphere is given by

I(sphere) = 2/3MR² + MR²

I(sphere) = 5/3MR²

Also, d = R

Substituting these into the first equation, we have

T = 2π * √[(5/3MR²) / (mgr)]

T = 2π * √[(5/3r) / (g)]

T = 2 * 3.142 * √(5/3 * 0.055) / (9.8)]

T = 6.284 * √(0.092/9.8)

T = 6.284 * √0.00939

T = 6.284 * 0.097

T = 0.6095 s

To 2 significant figures,

The period is 0.61 s

7 0

3 years ago

How does gravity affect potential energy?

wel

This is more along the lines of "Does gravity affext potential energy" Sort of. Potential energy is an odd one to imagine, sometimes. It's the energy possessed by an object or system by dint of it's spatial and mechanical configuration. That definition alone is perhaps not so useful...and it's certainly not official. But what it means is that an object can potentially have energy due to where it is or what state the system is in. Imagine we have a box and it's on the floor. The box, for all intents and purposes, has no potential energy. It isn't going anywhere and it just sits on the floor. It can't do any work in it's current position. Now we hoist the box into the air. For any distance the box travels from the floor, it gains potential energy. Now let's back track. We've changed the box's spatial configuration by hoisting it into the air and so have given it potential energy. Why does it now have potential energy? Because we can now drop the box (costing us no energy) and the box will fall. Maybe it falls onto a passer-by and injures them. Box on the floor = No energy. We lift the box = We spend our energy and give the box potential energy (as it wants to fall toward the ground). We drop the box = Potential energy is converted to kinetic energy as the box falls. Box injures someone = The kinetic energy has done work upon the person. So we can see how it all flows and connects. We have to put energy into the box to fight against gravity, but you can't destroy or create energy....so the energy we've spent is potentially stored 'inside' the box. Clearly, gravity effects a LOT of potential energies around us. In fact to some small extent, it's probably impossible to entirely avoid it's effects.

5 0

3 years ago

Doubly ionized lithium Li2+ (Z = 3) and triply ionized beryllium Be3+ (Z = 4) each emit a line spectrum. For a certain series of

EleoNora [17]

Answer:

tex]\lambda_{Be}[/tex] = 22.78 nm

Explanation:

Bohr's model for the hydrogen atom has been used by other atoms with a single electric charge by changing the number of charges by the charge of the new atom (atomic number)

$E_{n}$ = k e² / 2a₀ (1 /n²)

ao = h'² / k m e² h' = h/2πi

For another atom with a single electron in the last layer

a₀ ’= h’² / k m (Ze)²

a₀ ’= a₀ / Z²

Therefore, when replacing in the equation

$E_{n}$ = - Z² Eo/n²

E₀ = 13,606 eV

The transition occurs when the electron stops from one level to another

$E_{n}$ - $E_{m}$ = Z² E₀ (1 / n² - 1 / m²) = Z² ΔE

Let's relate this expression to the wavelength

c = λ f

E = h f

E = h c /λ

h c / λ = Z² ΔE

λ = 1 / Z² (hc / ΔE)

λ = 1 / Z² λ_hydrogen

Let's apply this last equation to our case

Lithium Z = 3

$E_{n}$ = - 9 Eo / n²

40.5 10-9 = 1/9 λ_hydrogen

Beryllium Z = 4

λ = 1/16 λ_hydrogen

Let's write our two equations is and solve

40.5 10-9 = 1/9 λ_hydrogen

tex]\lambda_{Be}[/tex] = 1/ 16 λ_hydrogen

40.5 10⁻⁹ = 1/9 (16 $\lambda_{Be}$ )

tex]\lambda_{Be}[/tex] = 40.5 9/16

tex]\lambda_{Be}[/tex] = 22.78 nm

6 0

3 years ago

How do base-isolators, the rubber and steel pads under some buildings, reduce earthquake damage?

nika2105 [10]

They absorb the energy of seismic waves.

Explanation:

Base - isolators, rubber and steel pads under buildings reduces earthquake damage by absorbing the energy of seismic waves.

Earthquakes are produced by the sudden release of energy within the earth which causes displacement and sharp movement on earth surface.
There are four main types of waves that are propagated by seismic waves which wrecks havoc.
Understanding the waves and their properties has been useful in designing earthquake resistant structures.
Base-isolators, rubber and steel pads helps to absorb seismic waves.
When seismic waves are absorbed, they are cut off.
This way they cannot cause damage.

learn more:

Earthquake brainly.com/question/6520403

#learnwithBrainly

8 0

3 years ago

Read 2 more answers