how has the model of an atom changed overtime?​

Answer:

Chemical properties of food are those properties that cannot be measured without altering the chemical composition of the food material.

Explanation:

Answer:

There are two types of reactions

no

its kinematics

the acceleration due to gravity and the initial vertical velocity are the only thing that affects vertical distance

No, the distance which it falls  vertically does not affect by its horizontal velocity.

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The percent yield is 74.4 %.

Fe₃O₄ + 4H₂ → 3Fe + 4H₂O

First, calculate the theoretical yield of H₂O.

Theor. yield =

0.112 g H

2

×

1 mol H

2

2.016 g H

2

×

4 mol H

2

O

4 mol H

2

×

18.02 g H

2

O

1 mol H

2

O

=

1.001 g H

2

O

Now calculate the percent yield.

% yield =

actual yield

theoretical yield

×

100

%

=

0.745 g

1.001 g

×

100

%

=

74.4

%

The mass in grams (theoretical yield) of hydrogen is produced is considered to be 0.119 g H2.

Since

Mass of Mg = 31.3 g

Mass of H2O = 2.12 g

First, we have to determine the mole

So,

Mole of Mg = mass of Mg / molar mass of Mg

= (31.3 g ) / (24.30 g/mol )

= 1.28 mole

And,

Mole of H2O = (2.12g ) / (18.01g /mol )

= 0.117 mole

As per the chemical reaction:

2 mole of H2O react with 1 mole of Mg

So, 0.117 mole of H2O will react with mole of Mg is

Now

= ( 1 mol Mg / 2 mol H2O ) * 0.117 mol H2O

= 0.058 mole of Mg

Now

1 mole of Mg produce , 1 mole of H2

So,

0.058 mole of Mg will produce 0.058 mole of H2

Now, determine the mass of H2

= Molar mass of H2 * mole of H2

= 2 * 0.058

= 0.116 g

= 0.119

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Answer:

Liquid

Explanation:

Solid would be made out of ice.

Explanation:

soild would be ice gas would be steam or evapiration

Answer:

Explanation:

Because the third shell is full, the rule of quantum mechanics prevent the third level from holding more than eight electrons.

The third level cannot accommodate more than eight electrons due to the fullness of the third shell and the laws of quantum physics.

Electrons are defined as a subatomic particle with a negative charge that makes up the nucleus of an atom along with protons and neutrons. Electrons are fundamental to many physical processes, including gravity, electromagnetic interactions, weak interactions, electricity, magnetism, chemistry, and thermal conductivity.

The laws of quantum physics are every moving particle, whether microscopic or macroscopic, has a wavelength according to De Broglie's equation. According to Heisenberg's Uncertainty Principle, it is impossible to measure a particle's position and momentum with the same level of accuracy.

Thus, the third level cannot accommodate more than eight electrons due to the fullness of the third shell and the laws of quantum physics.

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Answer:

Accretion

the process of growth or increase, typically by the gradual accumulation of additional layers or matter.

If you change the 2 in front of 2O, to a 3, the result of the right side of the equation is [tex]3CO_2+6H_2O[/tex]

Given the chemical equation expressed as:

[tex]CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O[/tex]

From the equation, we can see that 1 mole of methane reacts with 2 moles of oxygen to form 1 mole of carbon dioxide and 2 moles of water.

If the number of moles of oxygen is replaced with 3 moles, the correct equation will be expressed as:

[tex]3CH_4 + 2(3O_2) \rightarrow3CO2 + 6H2O[/tex]

This shows that if you change the 2 in front of 2O, to a 3, the result of the right side of the equation is [tex]3CO_2+6H_2O[/tex]

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Answer:

Simple Chemical Reactions Unit Test:

1. There is an extra O2 molecule left over.

2. Covalent bonds tend to be less polar than ionic bonds.

3. PH3

4. replacement

5. Potassium is more reactive than hydrogen.

6. Each carbon atom would share one pair of electrons with hydrogen and three pairs with the other carbon atom.

7. H2SO4 + 8HI → H2S + 4I2 + 4H2O

8. 2, 1, 2

9. Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is polar covalent, with oxygen pulling the electrons toward it.

10. Sodium donates an electron to chlorine.

11. selenium (Se)

12. bond type

13. six

14. K

15. indicator

Have a great day! :)

Answer:

In a fossil fuel power plant the chemical energy stored in fossil fuels such as coal, fuel oil, natural gas or oil shale and oxygen of the air is converted successively into thermal energy, mechanical energy and, finally, electrical energy.

Explanation:

Foods and beverages that are high in acids wear away the enamel that protects your teeth, a process known as tooth erosion. This changes the appearance of your teeth and opens the door for bacteria that can cause cavities or infection.

You can reduce tooth erosion from what you eat and drink by following these tips: Wait an hour before you brush after eating acidic foods to give your saliva a chance to naturally wash away acids and re-harden your enamel. Limit – or avoid – acidic beverages like soft drinks. If you do indulge, use a straw.

hope this helps you.

Explanation:

Tooth decay starts when pH of the mouth is lower than 5.5 .This is caused when bacteria present in the mouth produce acid by degradation of sugar and food particles remaining in the mouth after eating.

To prevent this, we should clean the mouth after eating food. Using toothpaste, which are generally basic, for cleaning the teeth can neutralise the excess acid and prevent tooth decay.

Answer:

Volume

Explanation:

Density of a quantity of matter is its mass divided by its volume. External pressure pushes the atoms or molecules closer together and increased temperature usually expands the volume of the material, pushing the molecules apart.

Answer: sulfur-36

Explanation:

Answer: C

Explanation:

When an insoluble substance is mixed with water, the substance will sink to the will remain solid and not dissolve (option D).

Insolubility is the quality of being insoluble i.e. cannot dissolve in a solvent.

Ideally, a solid substance called a solute mixes with solvent to form a solution. This occurs when the solute is soluble i.e. can dissolve in the solvent.

However, in a case whereby an insoluble substance is mixed with water, the substance will sink to the will remain solid and not dissolve.

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The mass of titanium metal formed is 148g.

The equation of the reaction is;

TiBr4(s) + 2H2(g) ------>Ti(s) + 4HBr(g)

The number of moles of hydrogen gas = 12.5 g/2.00 g/mol = 6.25 moles of hydrogen gas

If 2 moles of hydrogen gas yields 1 mole of titanium metal

6.25 moles of hydrogen gas yields 6.25 moles × 1 mole/2 moles = 3.1 moles of titanium metal

Mass of titanium metal = 3.1 moles of titanium metal × 47.8 g/mol = 148g

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Answer:

A. displacement) الازاحة

B. المسافة الفعلية للسيارة distance

You will calculate speed from graph (B) because it's the real distance, but (a) is Unreal distance

(II) speed equal distance / time

Speed =(250*1000/5*60*60).

=13.9888888m/s

Answer:

There are 4.59*10^-24 atoms in 15.00 of pure gold.

Explanation:

Molar mass of gold is 196.996g/mol

[tex]\frac{15}{196.966} =0.076 mol[/tex]

0.076*(6.022*10^-23)=4.59*10^-24

Taking into accoun the definitio of dilution,  if 0.250 L of a 6.00 M HNO₃ solution is diluted to 2.00 L, the molarity of the new solution is 0.75 M.

First of all, you have to know that dilution  is the reduction of concentration of a chemical substance in a solution and consists of lowering the amount of solute per unit volume of solution.

In other words, dilution is the procedure followed to prepare a less concentrated solution from a more concentrated one by simply adding more solvent to the solution.

In a dilution the amount of solute does not change, but as more solvent is added, the concentration of the solute decreases, as the volume (and weight) of the solution increases.

A dilution is mathematically expressed as:

Ci×Vi = Cf×Vf

where

In this case, you know:

Replacing in the definition of dilution:

6 M × 0.250 L= Cf × 2 L

Solving:

[tex]Cf=\frac{6 Mx0.250 L}{2 L}[/tex]

Cf=0.75 M

In summary, if 0.250 L of a 6.00 M HNO₃ solution is diluted to 2.00 L, the molarity of the new solution is 0.75 M.

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Answer:

hope its helpful. Good luck

Answer:

b.Rearrange the two equations to make each variable the focus (you will end up with three variations for each equation).

Answer:

Step 1 of 3

To determine pressures in each of the different units, you need the below relations:

(a) To convert pressure in atmospheres to mm Hg, use the relation given by,

We have, initial pressure charged to the system is 4.8 atm. So, the pressure in mm Hg is  So, the pressure in mm Hg is.Freon-12 is used as a refrigerant in central home air conditioners. The rate of effusion of Freon-12 to Freon-11 (molar mass = 137.4 g/mol) is 1.07:1. The formula of Freon-12 is one of the following:

\mathrm { CF } _ { 4 } , \mathrm { CF } _ { 3 } \mathrm { Cl }, \mathrm { CF } _ { 2 } \mathrm { Cl } _ { 2 } , \mathrm { CFCl } _ { 3 } , \text { or } \mathrm { CCl } _ { 4 }. CF  4 ,CF  3Cl,CF  2 Cl  2 ,CFCl  3 , or CCl  4

​

Explanation:

The system is initially charged to a pressure of 4.8 atm.  4.8 atm in mm Hg is 3648 mm Hg, 4.8 atm in torr is 3648 Torr, 4.8 atm in Pa is  486360Pa and 4.8 atm in Psi is 70.56 psi.

The force applied to a unit area of a surface is described by pressure, a fundamental concept in physics and chemistry. It describes how much force is distributed over a certain area.

A. mm Hg (millimeters of mercury):

1 atm = 760 mm Hg

So, 4.8 atm = 4.8 ×760 mm Hg

                   ≈ 3648 mm Hg

B. Torr:

1 atm = 760 Torr

So, 4.8 atm = 4.8 ×760 Torr

                   = 3648 Torr

C. Pa (Pascals):

1 atm = 101325 Pa

So, 4.8 atm = 4.8 × 101325 Pa

                   ≈ 486360Pa

D. psi (pounds per square inch):

Given: 1 atm = 14.7 psi

So, 4.8 atm = 4.8 ×14.7 psi

                  ≈ 70.56 psi

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Answer:

the smallest particle of a chemical element that can exist.

Answer:

the smallest imaginable thing

Explanation:

Answer:

NH4OH

Explanation:

NH4OH is a weak base because it partially dissociates into NH + and OH− ions in aqueous solutions and the amount of OH− ions produced is low.

Answer: see below

Explanation:

1. Change in smell

2. Heat given off

3. New substance (cake) cannot be separated into the original ingredients

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Answer:3

Explanation:

Molar mass of ( NH₄)₃PO₄ = 14.01×3 + 1.01×12 + 30.97 + 16.00×4 = 149.12 g/mol. Mass of 0.183 mol ...

A 0.183 mol sample of ammonium phosphate contains approximately 27.289 grams.

To calculate the number of grams in a given amount of a substance, we need to use its molar mass.

The chemical formula for ammonium phosphate is (NH₄)₃PO₄. To determine the molar mass, we sum up the atomic masses of all the atoms in the formula.

The atomic masses are as follows:

N = 14.007 g/mol

H = 1.008 g/mol

P = 30.974 g/mol

O = 15.999 g/mol

Now we can calculate the molar mass of ammonium phosphate:

Molar mass = (14.007 g/mol × 3) + (1.008 g/mol × 12) + (30.974 g/mol × 1) + (15.999 g/mol × 4)

Molar mass = 149.082 g/mol

Next, we can use the formula:

Mass = Number of moles × Molar mass

Mass = 0.183 mol × 149.082 g/mol

Mass ≈ 27.289 g

Therefore, a 0.183 mol sample of ammonium phosphate contains approximately 27.289 grams.

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The reaction as shown is a combustion reaction. 29.8 kCal of heat is produced when 4.20 g of ethanol reacts with O2 gas.

The equation of this reaction is shown below;

C2H5OH + 3O2 →2CO2(g)+3H2O(l)+327 kcal

From the reaction equation, we can see that 1 mole of ethanol produces 327 kcal of heat.

Now, we have to find the number of moles in  4.20 g of ethanol  as follows;

Number of moles = mass/molar mass = 4.20 g/46 g/mol = 0.091 moles

If 1 mole of ethanol yields 327 kcal of heat

0.091 moles of ethanol yields 0.091 moles × 327 kcal / 1 mole

= 29.8 kCal

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Answer:

To calculate the average atomic mass, multiply the fraction by the mass number for each isotope, then add them together.

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Answer:

C

Explanation:

Problem:

a solid is 5 cm tall 3 cm wide and 2 cm stick it has a mass of 129 g what is its density

Answer:

[tex]\sf{4.3g/cm³}[/tex]

Solution:

To achieve a volume of 30, multiply 5,3, and 2 together. Density is defined as the ratio of mass to volume, thus divide 129 by 30. You'd obtain a mass of 4.3.

Answer:

It will take the car 13.5 minutes to travel 3.5 miles.