7. Which of the following physical changes is experienced by women during the luteal stage of the

The price of gold is $40.63/g. How many kg of gold would be worth $100?

lora16 [44]

Answer:

0.00246kg

Explanation:

1g = $40.63

$100 = $100/40.63 = 2.46g

2.46/1000 g = 0.00246kg

3 0

3 years ago

PLEASE ANSWER Which is/are true?

Alona [7]

You have to check each statement, so this is equivalent to 5 different questions.

Answers:

The true statements are:

b. Si has valence electrons in the n = 3 energy level.

d. Xe has valence electrons in the n = 5 energy level.

Explanations:

a. Li has valence electrons in the n = 1 energy level.

Answer: False.

Valence electrons are the electrons in the outermost main energy level (shell of electrons).

To determine where the valence electrons are, you build the electron configuration, using Aufbau rules to predict the orbital filling: in increasing order of energy.

The atomic number of lithium (Li) is 3. Hence, you have to distribute 3 electrons, and so its electron confiuration is:

1s² 2s¹

The only valence electron is in the 2s orbital, i.e. in the n = 2 energy level.

b. Si has valence electrons in the n = 3 energy level.

Answer: True

Silicon (Si) has atomic number 14, so you have to distribute 14 electrons in increasing order of energy:

1s² 2s² 2p⁶ 3s² 3p²

Thus, Si has five valence electrons, and they are in the n = 3 energy level.

c. Ga has valence electrons in the n = 3 energy level.

Answer: False

Gallium has atomic number 31, so you have to distribute 31 electrons, filling the orbitals in increasing order of enery.

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p¹

The highest energy level is 4. This is where the valence electrons are. So, Ga has the valence electrons in the n = 4 level (not n = 3 as the statement describes).

d. Xe has valence electrons in the n = 5 energy level.

Answer: True

The atomic number of Xe is 54.

Using the short notation (noble gas notation), and filling the orbitals in increasing order of energy, you get the configuration:

[Kr] 5s² 4d¹⁰ 5p⁶.

Hence, the valence electrons are in the n ) 5 level, such as the statement describes.

e. P has valence electrons in the n = 2 energy level.

Answer: False

Phosphorus (P) has atomic number 15, hence there are 15 electrons.

The electron configuration following the increasing order of energy, which you can remember using Aufbau rules, is:

1s² 2s² 3s² 3p³

Then, the valence electrons are in the n = 3 energy level; not in the n = 2 energy level.

3 0

3 years ago

Kai was 200 meters north of the library when he remembered he had to return some books to the library .it took him seconds to do

galben [10]

Answer:

His speed was 2 m/s, and his velocity was 0. So it is B

Explanation:

took the test

8 0

3 years ago

Enter a formula in cell b7 to calculate the average value of cells b2:b6

AVprozaik [17]

In order to calculate the average value of cells B2:B6, you need to enter the formula on cell B7, On the Home tab, in the Editing group, click the Sum (AutoSum) button arrow and select Average . (and press Enter). The answer in this question is On the Home tab, in the Editing group, click the Sum (AutoSum) button arrow and select Average . (and press Enter).

6 0

2 years ago

Please help I don't have much time, I have 8 questions.

ValentinkaMS [17]

Answer:

1) The law of reflection states that the angles of incidence and reflection will always be congruent (option B)

2) If light passes from a gas to a liquid, it will slow down causing it to bend toward the source (option C).

3) Light travels fastest through a vacuum because particles are unobstructed since there are no media (option d).

4) Why do we see objects in color? Some wavelengths of light are reflected and some are absorbed (option d).

5) How are we able to see objects? Light is reflected (option d).

6) A ray of light passes from one medium to another and speeds up. As a result, it will bend away from the source of light (option c).

7) When light passes from one medium to another, it bends. What is this called? Refraction (option b).

8) Light hits a rough, textured surface. The beams split and reflect many different directions. This is called diffusion and will cause an image to clear (option b).

Explanation:

1) Light reflection consists of the bouncing of a beam of light against a polished surface, such as a mirror. This produces: an incident beam of light, a reflected beam of light, a point of incidence and two angles produced by the incident and reflected beam.

Since the angle of incidence is equal to the angle of reflection it can be said that both are congruent.

2) The passage of a ray of light from one medium to another is called refraction and involves a change in the speed and direction of the ray, due to the change in density from one medium to another.

The passage of light from a gaseous medium (less dense) to a liquid medium (more dense) produces a decrease in its speed and a shorter angle of refraction than that of incidence, so that the light is observed closer to the source.

3) The speed of light in a vacuum will always be higher because it does not depend on factors such as electricity or magnetism that get in its way, it is estimated to be near 300k m/s -exactly 299.792,46 meters per second- and is a constant value.

Obviously, the speed of light in any medium, such as gas, liquid or gel, will be lower than the speed of light in a vacuum.

4) White or visible light consists of the combination of all the colours of the light spectrum, which when combined give the light a clear appearance. An example of this is the decomposition of white light when passing through a prism or a drop of water.

The ability to perceive colors is due to visible light reflected on an object, where each color has a different wavelength. In the same way, absorbed light beams will not be visible.

5) When light "hits" an object, the reflected waves make it possible for that object to be seen, which is more difficult when the object is transparent.

This action of light on objects also allows us to appreciate their characteristics, such as shape, size, texture and color, differentiating and recognizing them thanks to these characteristics.

6) Due to the refraction of light, the passage of a ray of light from a dense medium to one of lower density - as from a liquid medium to a gaseous medium - causes its speed to increase, while the angle of refraction will be greater.

As a consequence of the open angle of refraction, the refracted light will be observed far from the light source (it will bend away from the source of light).

7) Refraction is a physical phenomenon that consists of the variation of speed and direction that light acquires when it passes from one medium to another.

In general, the different media have differences in their densities, on which the changes that occur in the waves when they pass through them depend, which is called refractive index. This index is different in each case, and influences the direction and speed of propagation of a wave.

8) Light diffusion occurs when light hits an opaque and irregular surface, causing rays to be scattered in several directions. This usually produces an effect of lightness on the illuminated objects.

Unlike reflection, light diffusion has multiple points of incidence, which generate various angles, responsible for the scattering of light.

5 0

3 years ago