How do elements tend to structure the molecules of life?

Answer:

LIGHT

AIR

SHELTER

FOOD

WATER

Answer:

light

air

shelter

food

water

Answer:

Mass of iron oxide: 79.85 g  

Explanation:

Given data:

Mass of iron = 112 g

Mass of O₂ = 24 g

Mass of iron oxide formed = ?

Solution:

4Fe + 3O₂         →       2Fe₂O₃

Number of moles of Fe:

Number of moles = mass/ molar mass

Number of moles = 112 g/ 55.85 g/mol

Number of moles =  2 mol

Number of moles of O₂:

Number of moles = mass/ molar mass

Number of moles = 24 g/ 32 g/mol

Number of moles =  0.75 mol

Now we will compare the moles of oxygen and iron with iron oxide.

                 Fe           :             Fe₂O₃

                 4             :                2

                 2             :                2/4×2 =  1

                O₂            :             Fe₂O₃

                 3             :                2

                 0.75       :                2/3×0.75 =  0.5

The number of moles of iron oxide formed by oxygen are less thus it will be limiting reactant.

Mass of iron oxide:

Mass = number of moles × molar mass

Mass = 0.5 mol  × 159.69 g/mol

Mass = 79.85 g  

Answer:

136 g Fe2O3

Explanation:

study island

Answer:

Number of atoms of elements are same on left and right side of balance equation.

Explanation:

Every chemical reaction must follow the law of conservation of mass. According to which mass can neither be created nor destroy but it change from one to another form. It means mass remain conserved. That is why we need to balance the chemical equation because mass remain same on both side of equation. Consider the example,

Chemical equation:

N₂ + H₂    →   NH₃

We can see that nitrogen and hydrogen react with each other and from ammonia. We need to balance the equation to have equal amount on both side.

Balance chemical  equation:

N₂ + 3H₂    →   2NH₃

It means mass remain same but change from one to another form.

A balanced equation is one that is having a chemical reaction where the numbers of atoms. Here the number of elements in each reaction and the total charges are the same. This includes both the reactant and the product.

Learn more about the same on the left and right sides of a balanced equation.

brainly.ph/question/20750343.

Answer:

39

Explanation:

Electrons weigh almost nothing, so their mass doesn't really matter for these types of problems. Just subtract 118-79 to find the remaining mass which is for the neutrons.

Answer:

Transfer of heat through direct physical contact

Explanation:

The meaning of conduction is the transfer of heat directly transmitted through a substance when there is the difference between temperature and electrical potential. Hope it helps!

Answer:

B

Explanation:

Answer:

This is physical not chemical because a chemical example would be boiling water over the stove.

Explanation:

D. The surroundings absorb 15 kJ of potential energy.

Chemical bonds = potential energy

ΔH reaction from bond energy is a breaking and forming reaction of the 2 reacting molecules

Can be formulated:

ΔH rxn =  ∑ the energy of the reagent bonds broken - ∑ the energy of the bonds formed by the product

The bond energy of the products is 67 kJ and reactants 52 kJ

[tex]\tt \Delta H_{rxn}=52-67=-15~kJ[/tex]

ΔH = negative ⇒The reaction is exothermic(releases heat to surrounding)

Answer:

C is right

Explanation:

Answer:

45N

Explanation:

force=mass×acceleration

Answer:

Supersaturated !

Explanation:

Answer:

Total atoms in 0.550g of =1.631x1022

Explanation:

answer is above

Answer:

2.322 half-lives have passed to decay down from 150 miligrams to 30 miligrams.

Explanation:

The half of Technetium-99 is approximately 211000 years. The decay of isotopes is represented by the following ordinary differential equation:

[tex]\frac{dm}{dt} = -\frac{m}{\tau}[/tex] (Eq. 1)

Where:

[tex]\frac{dm}{dt}[/tex] - First derivative of isotope mass in time, measured in miligrams per year.

[tex]m[/tex] - Mass of the isotope, measured in miligrams.

[tex]\tau[/tex] - Time constant, measured in years.

Now we proceed to obtain the solution of this differential equation:

[tex]\frac{dm}{m} = -\frac{dt}{\tau}[/tex]

[tex]\int {\frac{dm}{m} } = -\frac{1}{\tau}\int dt[/tex]

[tex]\ln m = -\frac{t}{\tau}+C[/tex]

[tex]m(t) = m_{o}\cdot e^{-\frac{t}{\tau} }[/tex] (Eq. 2)

Where:

[tex]m_{o}[/tex] - Initial mass of the isotope, measured in miligrams.

[tex]t[/tex] - Time, measured in years.

The time passed for isotope is cleared within the equation described above:

[tex]\ln \frac{m}{m_{o}} = -\frac{t}{\tau}[/tex]

[tex]t = -\tau \cdot \ln \frac{m}{m_{o}}[/tex]

In addition, we can obtain the time constant as a function of half-life:

[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex] (Eq. 3)

If we know that [tex]t_{1/2} = 211000\,yr[/tex], [tex]m_{o} = 150\,mg[/tex] and [tex]m = 30\,mg[/tex], then the time passed is:

[tex]\tau = \frac{211000\,yr}{\ln 2}[/tex]

[tex]\tau \approx 304408.654\,yr[/tex]

[tex]t = -(304408.654\,yr)\cdot \ln \left(\frac{30\,mg}{150\,mg} \right)[/tex]

[tex]t \approx 489926.829\,yr[/tex]

The amount of passed half-lives is that time divided by a half-life. That is:

[tex]n = \frac{489926.829\,yr}{211000\,yr}[/tex]

[tex]n = 2.322[/tex]

2.322 half-lives have passed to decay down from 150 miligrams to 30 miligrams.

Answer:

What are the times and is that your question?

Explanation:

Answer:

I think all of the above

Explanation:

Put as brainliest if you wish

Answer:

Answer

The answer is option 4

The energy transformation during nutrients transportation across the cell membrane is transformation from chemical energy to kinetic energy, where the uphill and downhill movements of molecules based on concentration gradient carries the whole process.

The total energy in a system is always conserved. However, one form of energy can be transformed into another form. For example we uses electrical devices such as bulbs fan etc, wherever the energy transformation is getting way from electrical energy to light or mechanical energy.

In plant cells nutrient molecules and ions are balanced inside and outside the cell and hence they are transported across the cell membrane by a concentration gradient with a chemical energy produced by the molecules.

The chemical energy inside of the ions and molecules converts to kinetic energy to transport itself through downhill and uphill mechanisms with aid of various enzymes and electron channels.

To find more on energy transformation, refer here:

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Answer:

solid has definite shape and volume.

liquid do not have definite shape but have definite volume.

gas do not have definite shape and definite volume.

solid have lowest compressibility out of three, liquid have more compressibility than solid but less than gases. gases have the highest compressibility out of three. Molecules in the solid phase have the least amount of energy, while gas particles have the greatest amount of energy. The temperature of a substance is a measure of the average kinetic energy of the particles.

Answer: conducting impulses

Explanation:

just did it on edge

Answer:

c. conducting impulses.

Explanation:

got it right on edg, hope this helps!

Answer:

A physical change

Explanation:

Cause when sharpening a pencil the led stays as led and only changes the height of it not the composition of it

Answer:

3 elements

Explanation:

The elements are:

- Chromium

- Hydrogen

- Oxygen

Answer:

.0924 moles of NaCl

Explanation:

So you know you have 5.4 g of NaCl and you need to know how many moles there are in this amount of NaCl

Add these two together----> 22.99 + 35.45 = 58.44

Now you can calculate for moles

Written-out method:

5.4 grams of NaCl  |   1 mole of  NaCl              

                                | 58.44 grams NaCl                = .0924 moles of NaCl

Plug into calculator method:

(5.4 g of NaCl/ 58.44g NaCl= .0925 moles)

Answer:

Your house could catch fire because while Nail Polish Remover itself isn't particularly flammable, the vapors it gives off are. Because of this, sparks could occur if nail polish is used near open flame or was tossed in, and then the sparks could catch onto something else and grow. I would not recommend trying this.

Explanation:

Answer:

It acts as a force upon it like in newtons first law of motion an object in motion will stay in motion until a force acts upon it So friction bascicallly slows it down or stops it completly

Explanation:

Answer:

[tex]m_{Al}=3.38gAl[/tex]

[tex]Y=83.1\%[/tex]

Explanation:

Hello.

In this case, for the given balanced reaction:

[tex]Fe_2O_3(s) + 2Al(s)\rightarrow 2Fe(s) + Al_2O_3(s)[/tex]

For 10.0 g of iron (III) oxide (molar mass = 160 g/mol), based on the 1:2 mole ratio with Al (atomic mass = 27 g/mol), the required mass is then:

[tex]m_{Al}=10.0gFe_2O_3*\frac{1molFe_2O_3}{160gFe_2O_3} *\frac{2molAl}{1molFe_2O_3} *\frac{27gAl}{1molAl} \\\\m_{Al}=3.38gAl[/tex]

Moreover, as 5.3 g of aluminum oxide are actually yielded, from the 10.0 g of iron (III) oxide, we can compute the theoretical mass of aluminum oxide (molar mass = 102 g/mol) via their 1:1 mole ratio:

[tex]m_{Al_2O_3}=10.0gFe_2O_3*\frac{1molFe_2O_3}{160gFe_2O_3} *\frac{1molAl_2O_3}{1molFe_2O_3} *\frac{102gAl_2O_3}{1molAl_2O_3} \\\\m_{Al_2O_3}=6.38gAl_2O_3[/tex]

Thus, the percent yield (actual/theoretical*100%) turns out:

[tex]Y=\frac{5.3 g}{6.38 g}* 100\%\\\\Y=83.1\%[/tex]

Best regards.

Answer:

closely packed cells

many cell junctions

Explanation:

Answer:

A,B

Explanation:

EDGE2021

Answer:

C)1 and 3 only☺️

Explanation:

Answer:

True

Explanation:

They are actually the same

The answer is False.

The oxidation number is the number of electrons removed or added to an element or compound. This is also equal to the charge on the ion.

For example, if Sodium atom loses one electron, it becomes oxidized to the + 1 state.

Na → Na⁺ + e⁻.

So, the oxidation number of Sodium is the charge on the Sodium ion which is + 1.

So, the oxidation number is equal to the charge on the ion.

So, the answer is False.

Learn more about oxidation number here:

https://brainly.com/question/166558

Answer:transition metal ionic compound with nonmetal anion

Explanation:

Answer:

Your answer is going to be D. transition metal ionic compound with nonmetal anion

Hope this helps :)

Answer:

286

Explanation:

Add atomic mass of all the Isotopes,

                                          Outcome = 825

divide it by number of isotopes which is 4 because there are 4 isotopes

                       Atomic mass of x = [tex]\frac{825}{4}[/tex]

                       Atomic mass of x is 286

The atomic mass of the unknown element X is 206 amu. Thus option B is correct.

Atomic mass is defined as the relative mass of the element's atom in comparison to the mass of an atom of the C12 isotope.

In an example, the general atomic mass is the average of the atomic masses of a large number of different isotopes.

First we added atomic mass of each isotopes

= 204 + 206 + 207 + 208 = 824

Now to calculate the atomic mass of element X we divide it by 4 as there is four isotopes

So, atomic mass = 824 / 4

                           = 206 amu

Thus, the atomic mass of the unknown element X is 206 amu. Thus option B is correct.

To learn more about atomic mass, refer to the link below:

https://brainly.com/question/17067547

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