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Don’t understand

Answer:

I think the answer is false

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.

Answer:

x = w/v

General Formulas and Concepts:

Pre-Algebra

Explanation:

Step 1: Define

v = w/x

Step 2: Solve for x

Explanation:

Objects with a lower density will float while objects with a higher density will sink.

Since 0.8g/cm³ < 1.0g/cm³,

The log will float in freshwater.

Answer:

A chemical equation is the symbolic representation of a chemical reaction. The reactants (the starting substances) are written on the left, and the products (the substances found in the chemical reaction) are written on the right.

Explanation:

pliz mark brainliest

Explanation:

chemical equations are used to represent a certain reaction between reactants to form products.

Answer:

B

Explanation:

bonding is a process of two different atoms sharing electrons for stability and these electrons are attracted by one atom losing it's electrons to another

Answer:

Nobelium or Beryllium

Answer:

......................

nh42so4

Answer:

Because while our lakes are Great, they're comparatively much smaller than oceans. And the gravitational pull isn't strong.

Answer:

D) none of these

Explanation:

Answer:

1250L or 1.25*10^3

Explanation:

Use the combined gas law, [tex]\frac{P_{1} V_{1}}{T_{1} }[/tex]=[tex]\frac{P_{2}V_{2}}{T_{2} }[/tex]

Put the value for the temperature(in Kelvin) and volume, and you can just put 1 for P1 and P2 because it stays the same.

I'll assume that you meant to put 1.10*10^3L

Answer:

Coefficients represents no of moles while subscripts represent no of atoms.

Answer:

Coefficients came before formula . Example = 4CO means there are 4 molecules of carbonmonooxide.

Subscripts came after and below the formula . Example = Oxygen gas in which 2 is a subscript which means there are 2 atoms of Oxygen in 1 molecule of Oxygen i.e. oxygen gas

Answer:

[Na]^+ [Cl]^-

Explanation:

Lets say its sodium, its number of electrons is 11, but when its stable (an ion), it is 10. and chloride, number of electrons is 17, but when its stable (an ion) it is 18. So the lewis structure for that is, remember with the straight brackets (not sure what it's called, but you know what I mean I guess) its this one: [ ]

Sodium will be + because it has more protons (11-10 = +1), and chloride will be - because it gained an electron, so has more electrons than protons (17-18 = -1)

So the lewis structure would be:

[Na]^+  for sodium

and

[Cl]^- for chlorine

Sodium chloride:

[Na]^+ [Cl]^-

Also just to add, only 1 of each atom (Na and Cl) was needed for the bonding, but if let's say example; 2 Cl was needed to bond with sodium, there would be 2 Cl (same) and 1 Na.

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

The reason why chemists synthesize polymers in the lab is;

because of the need to perform and observe the results of a variety of synthesized polymer reactions and to predict when a reaction will happen.

      Polymers are simply defined as a substance or material made up of long repeating chemical chains of molecules.

     Now, polymer synthesis is simply called polymerization and it is the process by which smaller molecules called monomers undergo covalent bonding to form a longer polymer chain.

      Now, from the definition above, the reason why chemists synthesize polymers in the lab is because of the need to perform and observe the results of a variety of synthesized polymer reactions and to predict when a reaction will happen.

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Answer:

P₂ =  3.19 atm

Explanation:

Given data:

Initial volume = 700 mL

Initial pressure = 1 atm

Initial temperature = 273K

Final temperature =100°C (100+273= 373 K)

Final volume = 300 mL

Final pressure = ?

Formula:  

P₁V₁/T₁ = P₂V₂/T₂  

P₁ = Initial pressure

V₁ = Initial volume

T₁ = Initial temperature

P₂ = Final pressure

V₂ = Final volume

T₂ = Final temperature

Solution:

P₂ = P₁V₁ T₂/ T₁ V₂  

P₂ = 1 atm × 700 mL × 373K / 273 K ×300 mL  

P₂ = 261100 atm .mL. K   /81900 K .mL

P₂ =  3.19 atm

Answer:

Yes.

Explanation:

Yes,  both the first and second element in the formula of covalent compound always receive  a prefix to represent the number of each element present in the formula in order to show the percentage or proportion of each element in the formula of covalent compound. Prefix refers to  addition of word, letter, or number at the beginning of something so here number placed in front of element indicates the prefix.

Answer:

parts per billion

Explanation:

I took the quiz

Answer:

parts per billion

Explanation:

edge 2021

Answer:

pH = 4.164

Explanation:

The first process is to find the initial moles for the base (B) & the acid (HA)

i.e.

[tex]= \dfrac{27 mL \times 0.0758 \ moles \ \ of \ B}{1000 \ mL}[/tex]

[tex]=0.0020466[/tex]

[tex]\simeq 2.047\times 10^{-3} \ moles \ of \ B[/tex]

[tex]= \dfrac{27 mL \times 0.0553 \ moles \ \ of \ HA}{1000 \ mL}[/tex]

[tex]=0.0014931[/tex]

[tex]\simeq 1.493\times 10^{-3} \ moles \ of \ HA[/tex]

The acid with base reaction is expressed as;

          HA              +      B         →             A⁻            +         HB⁺

to    1.493 × 10⁻³       2.047 × 10⁻³             -                         -

    -  1.493 × 10⁻³       1.493 × 10⁻³         1.493 × 10⁻³         1.493 × 10⁻³

            0                    5.54 × 10⁻⁴         1.493 × 10⁻³         1.493 × 10⁻³

From observation; both the acid & base weak

Given that:

The pKa for base = 4.594

The pKa for acid = 3.235

Recall that;

pKa = -log Ka

So; Ka = [tex]\mathbf{10^{-Ka}}[/tex]

By applying this:

For Base; Ka = [tex]10^{-4.594}[/tex] = 2.5468 × 10⁻⁵

For Acid:  Ka = [tex]10^{ -3.235}[/tex] = 5.821 × 10⁻⁴

After the reaction; we have the base with its conjugate acid & conjugate base of acid; Thus, since the conjugate acid of the base possesses a higher value of K, it is likely it would be the one to define the pH of the solution.

By analyzing the system, we have:

              HB⁺         + H₂O           ↔           B          +            H₃O⁺

     [tex]\dfrac{1.493\times 10^{-3}}{0.1 \ L}[/tex]                                 [tex]\dfrac{5.54\times 10^{-4}}{0.1 \ L}[/tex]

to   0.01493 M                                 0.00554   M

  -      x                                                   x                                x

    0.01493 - x                                 0.00554 - x                     x

Thus;

[tex]2.5468 \times 10^{-5} = \dfrac{(0.00554 -x)\times x}{(0.01493-x)}[/tex]

Using the common ion effect;

0.00554 - x   [tex]\simeq[/tex]  0.00554   &

0.01493 -  x   [tex]\simeq[/tex]   0.01493

∴

[tex]x = \dfrac{2.5468 \times 10^{-5} \times 0.01493}{0.00554}[/tex]

x =  [H₃O⁺] = 6.8635  × 10⁻⁵

∴

pH = -log(6.8635  × 10⁻⁵)

pH = 4.164

Answer:

Ethanol

Explanation:

Given parameters:

Mass of the object  = 7g

volume of the object  = 10mL

Unknown:

The kind of substance it is = ?

Solution:

Since from the parameters, we can determine the density of the object. Density is an intensive property of substances.

So, we simply find the density and check a density table for the type of substance it is.

  Density is the mass per unit volume.

        Density  = [tex]\frac{mass}{volume}[/tex]

Let us take the volume to cm³;

             10mL  = 10cm³

      Density  = [tex]\frac{7}{10}[/tex] = 0.7g/cm³

This is most likely ethanol

Answer:

The Sun's gravitational pull keeps our planet orbiting the Sun. The motion of the Moon is affected by the gravity of the Sun AND the Earth. The Moon's gravity pulls on the Earth and makes the tides rise and fall every day. As the Moon passes over the ocean, there is a swell in the sea level.

Explanation:

The statement of factor that keeps Earth in orbit around the Sun is "the gravitational pull of the Sun."

The Sun is the primary star of our Solar System. The Earth revolves around our Sun, which really is a star. At a distance of around 93 million miles from the Sun, Earth is the third planet.

The fundamental force that governs the planets' orbits around the sun is gravity. While each planet does have its own gravity, which is determined by its size and speed of movement, orbit is determined by the gravity of the sun.

Our planet orbits the Sun due to it's gravitational pull. The Sun, as well as all of the planets and moons, are gravitationally bound together and circle all around solar system's centre of gravity.

The Sun's gravity is around 27.9 times that of Earth's, and it helps to govern the tides on Earth in a modest degree.

Hence the correct answer is the gravitational pull of the Sun.

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Answer:

-189.55°C

Explanation:

Given data:

Initial volume of gas = 3.6 L

Final volume of gas = 15.5 L

Initial temperature = ?

Final temperature = 87°C (87+273 = 360 K)

Solution:

The given problem will be solve through the Charles Law.

According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.

Mathematical expression:

V₁/T₁ = V₂/T₂

V₁ = Initial volume

T₁ = Initial temperature

V₂ = Final volume  

T₂ = Final temperature

Now we will put the values in formula.

V₁/T₁ = V₂/T₂

T₁  = V₁T₂  /V₂

T₁   = 3.6 L × 360 K / 15.5 L

T₁   = 1296 L.K / 15.5 L

T₁  = 83.6 K

Kelvin to °C:

83.6 K - 273.15 = -189.55°C

Answer:

a. chemical change

Explanation:

A chemical change can cause an odor, however a physical change cannot, and the use of thermal energy will only make an object colder, not give it an odor.

Answer:

True

Explanation:

When a force acts on an object, the object may change shape by bending, stretching or compressing - or a combination of all three shape changes.

Answer:

92.4%

Explanation:

The volume per cubic meter of sodium preoccupy by the sodium ions is

[tex]V_{Na} = n \times V[/tex]

where;

volume (V) of each Na atom   = [tex]\dfrac{ 4}{3} \pi r^3[/tex]

Radius of each ion = 97.3 pm = 97.3 × 10⁻¹²

no.of atoms in the sample n =  mass of the sample / ( molar mass / NA)

mass of the sample per cubic metre =  911 kg/m³

∴

[tex]V = \bigg [ \dfrac{4}{3} \pi r^3 \bigg ] \bigg [\dfrac{MN_A}{m} \bigg ][/tex]

[tex]V = \bigg [ \dfrac{4}{3} \pi (97.3 \times 10^{-12} )^3 \bigg ] \bigg [\dfrac{ (911 kg/m^3 (m^3))(6.023\times 10^{23})}{27.7 \times10^{-3}\ kg/mol } \bigg ][/tex]

V = 0.07643 m³

The fraction of available conduction electrons are;

= (1 - V)

= 1 - 0.07643

= 0.92357

≅ 92.4%

Answer:

oxidize

Explanation: