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is this a chemical or physical change???

Answer:D

Explanation:

Your skin makes vitamin D

Your skin prevents dehydration

And your skin maintains body temperature. So you are left with D

Answer:

The correct option is D.

works with bones to help you move

Explanation:

Skin is the outer layer of the body and it is the body's largest organ.

It protect the body from heat and other harmful substances.

It is comprises of three layers;

The Epidermis which is the outer layer.

The dermis which is a fibrous later that protect the Epidermis.

The subcutis is the subcutaneous layer that is beneath the dermis.

Function of the skin.

1. It's regulate body temperature

2. It's protect the body from heat and pathogenic entry.

3. It produces vitamin D

4. The skin allow sensations or feelings of touch, heat, and cold.

Therefore;

works with bones to help you move is wrong because it is the muscle that work with the bone.

1. A radical is a reactive intermediate with a single ____________ electron, formed by ____________ of a covalent bond.

1. A: Unpaired, and homolysis

2. Allylic radicals are stabilized by ____________ , making them ____________ stable than tertiary radicals.

2. A: Resonance, and more

3. A compound that contains an especially weak bond that serves as a source of radicals is called a radical ____________ .

3. A: Initiator

4. Treatment of cyclohexene with N-bromosuccinimide in the presence of light leads to ____________ by ____________ intermediates.

4. A: Allylic substitution by radical

ANSWER;

1s22s22p63s23p63d64s2

EXPLANATION;

Molecular orbital diagram for Fe.

In writing the electron configuration for Iron the first two electrons will go in the 1s orbital. Since 1s can only hold two electrons the next 2 electrons for Iron go in the 2s orbital. The next six electrons will go in the 2p orbital. The p orbital can hold up to six electrons. We'll put six in the 2p orbital and then put the next two electrons in the 3s. Since the 3s if now full we'll move to the 3p where we'll place the next six electrons. We now shift to the 4s orbital where we place the remaining two electrons. After the 4s is full we put the remaining six electrons in the 3d orbital and end with 3d6.

Therefore the Iron electron configuration will be 1s22s22p63s23p64s23d6.

Note that when writing the electron configuration for an atom like Fe, the 3d is usually written before the 4s. Both of the configurations have the correct numbers of electrons in each orbital, it is just a matter of how the electronic configuration notation is written

Therefore we have 1s22s22p63s23p63d64s2

Explanation:

Im not sure what the other trait is so I couldn't do phenotype. I hope this still helps though

Answer:

301.92 g of CaCl2.

Explanation:

The following data were obtained from the question:

Volume of CaCl2 solution = 3.20 L

Molarity of CaCl2 solution = 0.850 M

Mass of CaCl2 =?

Next, we shall determine the number of mole of CaCl2 in the solution. This can be obtained as illustrated below:

Volume of CaCl2 solution = 3.20 L

Molarity of CaCl2 solution = 0.850 M

Mole of CaCl2 =?

Molarity = mole /Volume

0.850 = mole of CaCl2 /3.20

Cross multiply

Mole of CaCl2 = 0.850 × 3.20

Mole of CaCl2 = 2.72 moles

Finally, we shall determine the mass of the CaCl2 needed to prepare the solution as follow:

Mole of CaCl2 = 2.72 moles

Molar mass of CaCl2 = 40 + (2×35.5)

=40 + 71

= 111 g/mol

Mass of CaCl2 =?

Mole = mass /Molar mass

2.72 = mass of CaCl2 /111

Cross multiply

Mass of CaCl2 = 2.72 × 111

Mass of CaCl2 = 301.92 g

Therefore, 301.92 g of CaCl2 is needed to prepare the solution.

Answer: Molar mass=28.224g/mol, The gas could be Nitrogen gas

Explanation:

Density is calculated as  Molar mass/ Molar Volume

Recall that

One mole of an ideal gas at (STP) standard temperature and pressure = 22.4 liters (in Volume)

Given That Density =1.26 g/L

Volume = 22.4L at STP,

Molar mass = Density x Molar Volume

= 1.26 g/L x 22.4L =28.224g

Therefore, if  1  mole of this gas has a mass of 28.224g  then  its molar mass is equal to 28.224g/mol

The molar mass of Nitrogen =  28.014 g/moL, so we can conclude the the gas could be Nitrogen

Answer:

E.none

Explanation:

because the bonds join with each other and no lone pair is left

Geologic Tools. Geologists use a lot of tools to aid their studies. Some of the most common tools used are compasses, rock hammers, hand lenses, and field books.

hope this helped <3

Answer:

Yes

Explanation:

Text me on here

Answer:

A

Explanation:

A is the correct answer once the warm, moist air moves into the cold, dry air, the thunderstorm will start to develop and gradually get larger.

Answer:

Concept: Chemical Analysis

Answer:

Hydrogen

Explanation:

Helium has an atomic number Z = 2, that is, it has 2 protons. Since it is electrically neutral it also has 2 electrons. Thus, the electron configuration of helium is 1s².

Hydrogen has an atomic number Z = 1, that is, it has 1 proton. Since it is electrically neutral it also has 1 electron. Thus, the electron configuration of hydrogen is 1s¹.

If hydrogen gains a single extra electron to form H¹⁻, it acquires the same electron configuration than helium.

Explanation:

The reason why it is important to prepare for an disaster is because Being prepared can reduce fear, anxiety, and losses that accompany disasters. People also can reduce the impact of disasters (flood proofing, elevating a home or moving a home out of one's harm's way, and securing items that could shake loose in an earthquake) and sometimes avoid the danger completely.

The things you need to prepare for an disaster is

Answer:

12.3 L

Explanation:

Now we have that the rate of diffusion of the saturated hydrocarbon is R1

Rate of diffusion of sulphur dioxide is R2

Molar mass of hydrocarbon is M1

Molar mass of sulphur dioxide is 64 gmol-1

From Graham's law;

R1/R2 = √64/M1

2/1 =√64/M1

(2/1)^2 = (√64/M1)^2

4/1 = 64/M1

4M1 =64

M1 = 16

To obtain the number of moles of the gas;

(n*12) + (2n + 2) 1 = 16

12n + 2n + 2 = 16

14n + 2 = 16

14n = 16 - 2

n = 14/14

n = 1

Hence the hydrocarbon is CH4

Volume occupied by CH4 at STP = 22.4 L

Hence;

P1 = 1 atm

T1 = 273 K

V1 = 22.4 L

T2 = 300 K

P2 = 2 atm

V2 = ?

P1V1/T1 = P2V2/T2

P1V1T2 = P2V2T1

V2 = P1V1T2/P2T1

V2 = 1 * 22.4 * 300/2 * 273

V2 = 12.3 L

The volume occupied by the hydrocarbon at 27 °C and 2 atm is 12.31 L

Let the hydrocarbon be initially at standard temperature and pressure (STP)

Thus, we can obtain the new volume of the hydrocarbon by using the combined gas equation as illustrated below:

P₁V₁ / T₁ = P₂V₂ / T₂

(1 × 22.4) / 273 = (2 × V₂) / 300

22.4 / 273 = (2 × V₂) / 300

Cross multiply

273 × 2 × V₂ = 22.4 × 300

546 × V₂ = 6720

Divide both side by 546

V₂ = 6720 / 546

V₂ = 12.31 L

Thus, the volume occupied by the hydrocarbon at 27 °C and 2 atm is 12.31 L

Learn more about gas laws:

https://brainly.com/question/25967416

Answer:

Propane gas plus oxygen gas produces water and carbon dioxide.

Explanation:

This is the initial chemical equation: C3H8 + O2 = CO2 + H2O

This is the balanced chemical equation: C3H8 + 5 O2 = 3 CO2 + 4 H2O

C3H8 + O2 → CO2 + H2O

C3H8 + 5O2 → 3CO2 + 4H2O

Learn more: https://brainly.com/question/7181548?referrer=searchResults

Answer: scientific explanation

Explanation:

A really good scientific explanation should do two main things: It should explain all the observations and data we have. It should allow us to make testable predictions that we can check using future experiments.

The concentration of iron used in the titration : 0.009 M

Given

Reaction

Cr₂O₇²⁻ + 6Fe²⁺ + 14H⁺ ⇒ 2Cr³⁺ + 6Fe³⁺ + 7H₂O

0.0093 mol/L potassium  dichromate

200 cm³ of dilute acid, 25cm³   was used in the titration.

Required

the concentration of iron

Solution

Titration formula

C₁V₁n₁=C₂V₂n₂⇒ From equation : n₁=6n₂(1=Cr₂O₇, 2=Fe)

titration average : 33+32.05+32.15+32.1 / 4 = 32.325 cm³(ml)

25 cm³ of iron solution used in titration :

[tex]\tt V_1=32.325~ml\\\\V_2=25~ml\\\\C_1=0.0093~M\\\\\\\\C_1.V_1.n_2=C_2.V_2.n_1\\\\0.0093\times 32.325\times 6=C_2\times 25\times 1\\\\C_2=0.07215~M[/tex]

Dilution(25 ml from 200 ml iron solution)

[tex]\tt C_2.V_2=C_1.V_1\\\\0.007215\times 25=C_1\times 200\\\\C_1=0.009~M[/tex]

Answer:

gene

Explanation:

Answer:

focuses light on the retina

Explanation:

Explanation:

yup,it is correct:-)

Answer:

the genotype would be 50% Rr and 50% rr

the phenotypes would be 50% Red flower (Rr) and 50% white flower (rr)

Explanation:

Answer:

86

Explanation:

The reaction that takes place is:

First we convert moles of ethanol to moles of water:

Then we convert moles of water to grams of water, using its molar mass:

So 84.6 grams of water will be produced.

The mass of water, H₂O produced when 1.6 moles of ethanol, C₂H₅OH are completely burned is 86.4 g

We'll begin by writing the balanced equation for the reaction. This is given below

C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O

From the balanced equation above,

1 mole of C₂H₅OH reacted to produce 3 moles of H₂O.

From the balanced equation above,

1 mole of C₂H₅OH reacted to produce 3 moles of H₂O.

Therefore,

1.6 moles of C₂H₅OH will react to produce = 1.6 × 3 = 4.8 moles of H₂O.

Mole of H₂O = 4.8 moles

Molar mass of H₂O = (2×1) + 16 = 18 g/mol

Mass = mole × molar mass

Mass of H₂O = 4.8 × 18

Thus, the mass of water obtained from the reaction is 86.4 g

Learn more: https://brainly.com/question/25656650

Answer: The vertical columns on the periodic table are called groups or families because of their similar chemical behavior. All the members of a family of elements have the same number of valence electrons and similar chemical properties. The horizontal rows on the periodic table are called periods

Explanation:

Intermolecular forces are electrostatic in nature and include van der Waals forces and hydrogen bonds. ... The three major types of intermolecular interactions are dipole–dipole interactions, London dispersion forces (these two are often referred to collectively as van der Waals forces), and hydrogen bonds.May 20, 2018

Answer:

27 days, 7 hours and 43 minutes.

Explanation:

To complete a full orbit around Earth, it takes 27 days, 7 hours and 43 minutes for the Moon. This is called sidereal month and is measured by the Moon's position relative to distant *fixed" stars.

Answer:

A and D then I guess

Explanation:

sorry hope this helps!

Answer:

So the answer to this question would be C. 400 J

Explanation:

Now for this problem, what is given is a 40 Newtons which would represent the force to be applied to the object, and a distance of 10 meters after the application of the said force. When these two combine, work is done. The unit for work is Joules and this is what we are looking for. The formula to get Joules or for work would be the force applied to the object multiplied by the distance that it travelled after the application of the force. It looks like this

work = force x distance

Joules = Newtons x meter

so let us substitute the variables to their corresponding places

Joules = 40 N x 10 m

Joules = 400 J

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