Similar cells with the same function, all working together for the same purpose, form the 2nd level of organization in an organism. This level is called a(n)

Answer:

by statistical analyses, especially by determining the p-value

Explanation:

In general, observations and results obtained from experimental procedures are subjected to a statistical test to check the robustness of the working hypothesis. The p-value is the most widely used statistical index in order to test such observations and results. The p-value is the statistical probability of obtaining extreme observed results when the null hypothesis is considered correct. A p-value lesser than 0.05 generally is considered statistically significant and then the null hypothesis can be rejected. In consequence, a very low p-value (which is obtained by statistical analysis of the observations and results), indicates that there is strong evidence in support of the alternative hypothesis.

Answer:

During a phase change no chemical bonds are broken. Atoms are not rearranged because a phase change is a physical change rather then a chemical change. However, intermolecular forces are almost entirely removed from the liquid since the intermolecular forces are what cause the liquid to be a liquid.

Explanation:the nature of the intermolecular forces (IMF) will not change when the state changes from solid to liquid, however, the number of IMF changes.

Answer:

See explanation and image attached

Explanation:

Let us consider the mechanism attached to this answer. This is only one of the ways of synthesizing the required product.

The starting material is acetylene. This is reacted with sodamide in ammonia alongside methyl iodide. The process is repeated again, this time using butyl iodide. The alkyne is now reduced using hydrogen.

The alkane formed may now be chlorinated in the presence of light using the chlorine molecule. A mixture of alkyl halides are obtained.

Answer:

C & E

Explanation:

Answer:

1.86moles

Explanation:

Given chemical reaction:

   2C₂H₆  +  7O₂  →  4CO₂  +  6H₂O

Mass of C₂H₆   = 18.6g

Unknown:

Number of moles of steam produced  = ?

Solution:

  2C₂H₆  +  7O₂  →  4CO₂  +  6H₂O

 We have checked and the equation is balanced.

Now, find the number of moles of C₂H₆ from the given mass;

   Number of moles  = [tex]\frac{mass}{molar mass}[/tex]  

 Molar mass of C₂H₆ = 2(12) + 6(1) = 30g/mol

  Number of moles  = [tex]\frac{18.6}{30}[/tex]   = 0.62moles

From the balanced reaction equation:

      2 mole of C₂H₆ will produce 6 moles of steam

     0.62 moles of C₂H₆  will therefore produce [tex]\frac{0.62 x 6}{2}[/tex]   = 1.86moles

Sodium-25 after 3 minutes : 1.0625 mg

General formulas used in decay:  

[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]

T = duration of decay  

t 1/2 = half-life  

N₀ = the number of initial radioactive atoms  

Nt = the number of radioactive atoms left after decaying during T time  

No=8 mg

t1/2=60 s

T=3 min=180 s

[tex]\tt Nt=No\dfrac{1}{2}^{T/t1/2}\\\\Nt=8.5\dfrac{1}{2}^{180/60}\\\\Nt=8.5(\dfrac{1}{2})^3\\\\Nt=1.0625~mg[/tex]

Answer:

amplitude= distance between midpoint of a wave and crest

crest= highest point of transverse wave

wavelength= distance traveled in one wave cycle

medium= matter distributed by energy

trough=lowest point of transverse wave

frequency=number of waves that pass per second

Explanation:

A wave is a dynamic perturbation of one or even more quantities that propagates in a specific medium.

A wave is a dynamic perturbation of one or even more quantities that propagates in physics, mathematics, or related sciences. When waves oscillate frequently around an equilibrium position at a certain frequency, they are said to be periodic. A traveling wave is one in which the whole waveform moves inside one direction; in contrast, a standing wave is one in which two periodic waves are overlaid and move in the opposing directions.

In a wave form, there are some points in which the wave amplitude seems reduced or even zero, and these positions have null vibration amplitudes. A wave equation or perhaps a one-way wave equation describing single wave propagation inside a specific direction is frequently used to describe waves.

amplitude= distance between midpoint of a wave and crest

crest= highest point of transverse wave

wavelength= distance traveled in one wave cycle

medium= matter distributed by energy

trough=lowest point of transverse wave

frequency=number of waves that pass per second

Therefore, a wave is a dynamic perturbation of one or even more quantities that propagates

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Answer:

Well, I have pet squirrels, and I know they get acorns and other food, and dig up certain spots on the ground, then put their food in there. And they have food for the winter.

Answer:

FALSE

Explanation:

right answer on plato:)

Explanation:

The angle strain arises from the compression of the ideal tetrahedral bond angle of 109.5° to 60°. The large torsional strain occurs since all CH bonds on adjacent carbons are eclipsed.

The lateral angle that decrease in the lateral angle from 109.5 to 60 degree so, these is the main source of angle strain and torsional strain present in cyclopropane.

Angle strain is the term for strain that results from departure from one or more ideal bond angles. Torsional strain is a chemical compound's resistance to bond twisting. Torsional strain between the bonds occurs when atoms separated by three bonds are arranged in an unstable staggered conformation rather than an eclipsed shape.

It exists in cyclopropane because its C-C-C bond angles must not exceed 60 degrees, which is less than the optimum bond angle of 109.5 degrees for tetrahedral carbon. It is the cause of these.

We are aware that three carbon atoms in a triangle plane break the cycle and cause each carbon to be sp3 hybridized. All carbon endeavors are sp3 hybridized, and we are aware that the sp3 hybrid angle is 109 degrees, 28 minutes at 109.5 degrees. But the single angle in cyclo-propane is only 60 degrees.

Personal strain results from the bending of bonds necessary to form a new molecule. The primary source of the angle strain and torsional strain found in cyclopropane is the decrease in lateral angle from 109.5 to 60 degrees.

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Answer:

COLD AND FLU!!!!

Explanation:

Answer:

CORONAVIRUS UGH

Explanation:

Reaction b,c and d could be written as net ionic equations.

The electrolyte in the solution produces ions.  

The equation of a chemical reaction can be expressed in the equation of the ions  

For strong electrolytes (the ionization rate = 1) is written in the form of separate ions, while the weak electrolyte (degree of ionization <1) is still written as an un-ionized molecule  

In the ion equation, there is a spectator ions that is the ion which does not react because it is present before and after the reaction  

When these ions are removed, the ionic equation is called the net ionic equation  

For gases and solids including water (H₂O(l)) can be written as an ionized molecule  

So only the dissolved compound is ionized ((expressed in symbol aq)  

To see the reaction can be expressed in terms of the net ionic equation, we must see that there are two or more ions that are the same from both sides of the reactant and the product in the form of aquoeus (because the form of compounds in the form of gases, solids and liquids will remain molecular and non-ionized)

CH4 (g) + 2 O2 (g) = CO2 (g) + 2 H2 O(g)

No⇒no compounds in the aqueous form

Cu(s) + 2 AgNO3 (aq) = 2 Ag(s) + Cu(NO3 )2 (aq)

Cu(s) + 2 Ag⁺+ 2NO3⁻ (aq) = 2 Ag(s) + Cu²⁺ +2NO3⁻ (aq)

Cu(s) + 2 Ag⁺(aq) = 2 Ag(s) + Cu²⁺(aq)

yes, because there are NO3 (spectators ion) on both sides

MgCl2 (aq) + 2 KOH(aq) = Mg(OH)2 (s) + 2 KCl(aq)

Mg²⁺(aq)+2Cl⁻ (aq) + 2K⁺(aq)+2OH⁻(aq) =  Mg(OH)2 (s)+ 2K⁺(aq)+2Cl⁻(aq)

Mg²⁺(aq)+2OH⁻(aq) =  Mg(OH)2 (s)

yes, because there are 2Cl⁻ (aq) and 2K⁺(aq (spectators ion) on both sides

CaCO3 (s) + 2 HCl(aq) = CaCl2 (aq) + CO2 (g) + H2 O(l)

CaCO3 (s) + 2 H⁺(aq)+2Cl⁻(aq) = Ca²⁺(aq)+2Cl⁻ (aq) + CO2 (g) + H2 O(l)

CaCO3 (s) + 2 H⁺(aq) = Ca²⁺(aq) + CO2 (g) + H2 O(l)

yes, because there are Cl⁻ (spectators ion) on both sides

Answer:

The correct option is D

Explanation:

A physical change is a change in which no new substance is formed and can be easily reversible.

Of the options provided, option D is correct because gaseous water (steam) can be converted to solid water (ice) through freezing and can be reversed by heating up the solid water. Thus, this process does not involve the formation of any new substance.

Note that the processes of freezing and heating described must pass through the liquid phase.

Answer:

that answer is B

Explanation:

the answer is b luv

Answer:

b

Explanation:

Answer:

0.33 mol

Explanation:

Given data:

Volume of balloon = 8.3 L

Temperature = 36°C

Pressure = 751 torr

Number of moles of hydrogen = ?

Solution:

Temperature = 36°C (27 +273 = 300 K)

Pressure = 751 torr (751/760= 0.988 atm)

Formula:

The given problem will be solve by using general gas equation,

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K  

T = temperature in kelvin

PV  = nRT

0.988 atm × 8.3 L  = n × 0.0821 atm.L/ mol.K  × 300 K

8.2 atm.L = n × 24.63 atm.L/ mol

n = 8.2 atm.L / 24.63 atm.L/ mol

n = 0.33 mol

Answer:

It is false

Explanation:

Barium does not gain electrons to make its valences shell full. In truth, Barium loses electrons to attain a complete octet configuration of its shell.

This is because, barium is electropositive and not electronegative.

Answer:

Explanation:

i hope it helps ;)

Answer:

Half life = 10.765 year

Explanation:

Given data:

Mass of sample = 500 Kg

Mass left after 21.53 years = 125 kg

Half life of substance = ?

Solution:

At tome zero = 500 kg

At 1st half life = 500 kg/2 = 250 kg

At 2nd half life = 250 kg/2 = 125 g

Half life:

Half life = time elapsed / number of half life

Half life = 21.53 year/2

Half life = 10.765 year

Answer:

Cr2(SO4)3

Explanation:

Answer:

the mirror is 12 cm away from the image

Explanation:

; the image will be virtual and it will form at 12 cm distance behind the mirror.

Answer:

Because of the existence of isotopes.

Answer:

Because of the existence of isotopes.

Answer:

CuS(s) + 2HCl(aq) —> CuCl2(aq) + H2S(g)

Explanation:

CuS(s) + HCl(aq) —> CuCl2(aq) + H2S(g)

The above equation can be balance by by doing the following:

CuS(s) + HCl(aq) —> CuCl2(aq) + H2S(g)

There are 2 atoms of H on the right side and 1 atom on the left side. It can be balance by putting 2 in front of HCl as shown below:

CuS(s) + 2HCl(aq) —> CuCl2(aq) + H2S(g)

Now the equation is balanced since the number of atoms present in the elements are the same on both side of the equation i.e

Reactant:

Cu = 1

S = 1

H = 2

Cl = 2

Product:

Cu = 1

S = 1

H = 2

Cl = 2

Therefore, the balanced equation is:

CuS(s) + 2HCl(aq) —> CuCl2(aq) + H2S(g)

Answer:

15%

85%

Explanation:

Let the natural abundance of Fe-55  = y

      the natural abundance of Fe - 56  = 1-y

Average atomic mass = 55.85

Unknown:

Percent abundances of each isotope = ?

Solution;

The average atomic mass of a substance is given as;

  Average atomic mass  =  (mass x abundance)Fe - 55 + (mass x abundance)Fe - 56

Now insert the parameters and solve;

55.85  = (55 x y) + [56 x(1-y)]

 55.85  = 55y + 56 - 56y

 55.85  = -y + 56

  55.85 - 56  = -y

  -0.15 = -y

     y  = 0.15

1-y  = 1 - 0.15  = 0.85

Percentage abundance;

   Fe - 55  = 0.15 x 100  = 15%

   Fe - 56  = 0.85 x 100  = 85%

Answer:

the volume increases

Explanation:

Explanation:

The specific heat capacity is the amount of heat required to raise the temperature of 1mole or 1kg or 1g of substance by 1k or 1°C

This property is an intensive property of matter and does not depend on the quantity of matter present.

 Some of the unit of specific heat are;

J/g°C, J/kg°C, J/mol°C, J/molK , Cal/g°C

Answer: c

Explanation:

Answer:

when you drown your lungs fill up with water so it like severe pain that won't go away until your dead so it like drink milk through nose imagine that and you can't breath that is what it is like to drown

Explanation:

Answer:

D) the higher the frequency the greater the energy of light.

Explanation:

Energy and frequency of light are directly connected. The higher the frequency ,the greater the energy of light.

As frequency increases, the energy of light also increases.

Mathematically;

 Energy  = hf

   h is planck's constant

   f is the frequency.