HELP
Between steps 2 and 3, the chemical energy in the coal is converted to

Answer:

The chromium found in foods will not hurt you. But taking excessive chromium supplements can lead to stomach problems and low blood sugar (hypoglycemia). Too much chromium from supplements can also damage the liver, kidneys, and nerves, and it may cause irregular heart rhythm.

Answer:

Synthesis

Explanation:

Nothing else works

Answer:

Calcium

Explanation:

It is because sodium and potassium are highly reactive metal i.e. Group 1 but calcium is Group 2 element. So, calcium is least reactive.

Answer:

It's true

Explanation:

Uhhh, the internet! lol.

Answer:

Explanation: Because the order of elements is based on atomic number, vertical families share similar chemical properties.

Answer:

Would be C

Explanation:

helpig and bringing noice to a persons safety is always the right thing. C is correct, hope this helps

Answer: I believe -3

Explanation:

Answer:

it is iodine it seems very right

The question is incomplete, the complete question is;

In this stoichiometry problem, determine the percentage yield:

Excess aluminum metal reacts with aqueous nickel(II) sulfate to produce aqueous aluminum sulfate and nickel as a precipitate. In this reaction 108 g of aluminum were combined with 464 g of nickel(II) sulfate to produce 274 g of aluminum sulfate.

Answer:

80%

Explanation:

The correct equation for this reaction is;

2Al(s) + 3NiSO4(aq) --------> Al2(SO4)3 + 3Ni(s)

We already know that Al is in excess then NiSO4 is the limiting reactant.

Hence, Number of moles in 464 g of NiSO4 = mass/ molar mass

Molar mass of NiSO4 = 155 g/mol

Number of moles = 464g/155g/mol = 2.99 moles

Number of moles of Al2(SO4)3 = mass/molar mass

molar mass = 342 g/mol

So, Number of moles = 274g/342g/mol = 0.8 moles

Given the stoichiometric reaction equation;

3 moles of NiSO4 yields 1 mole of Al2(SO4)3

2.99 moles of NiSO4 yields 2.99 * 1/3 = 1 mole of Al2(SO4)3

percentage yield is given by; actual yield/ theoretical yield * 100/1

actual yield =  0.8 moles of Al2(SO4)3

Theoretical yield = 1 mole of Al2(SO4)3

Hence;

% yield = 0.8/1 * 100 = 80%

Answer:

metamorphic

Explanation:

when one rock changes another rock the rock that got changed is now metamorphic

Answer:

B. chemical

Explanation:

Chemical change cannot go back to its original form

Answer:

B

Explanation:

bubbles is a form of chemical change :)

Answer:

1.The law does not hold true if the different isotopes of the element are involved in making chemical compound.

2.The law is not applicable when elements combine in the same ratio but different compounds are formed.

Answer:

a form of energy that harnesses the power of water in motion—such as water flowing over a waterfall—to generate electricity.

Explanation

Water boils when the vapour pressure is least the atmospheric pressure.

The atmospheric pressure is equal at the top of the mountain.

The air around you has weight, and it presses against everything it touches. That pressure is called atmospheric pressure, or air pressure. It is the force exerted on a surface by the air above it as gravity pulls it to Earth.

As we go up in altitude the air pressure becomes less. When the pressure decreases, it takes less energy to get the water molecules to escape the surface. So the temperature is less than it would be at sea level.

Air pressure is higher or greater at the bottom of a mountain. This is because the height of the air above that level is thicker than at the top.

Pressure is given by the equation, P=rho*g*h, where rho is the air density, g is the gravity value and h is the thickness of the air layer on top of the level where we are considering the pressure.

Therefore, as we can see, at the bottom of the mountain, the thickness h of air is greater, and so is the pressure.

Hence, water boils when the vapour pressure is least the atmospheric pressure and the atmospheric pressure is equal at the top of the mountain.

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Answer:

18.01528 grams.

Explanation:

Ther are 0.84 moles of [tex]H_{2}O[/tex] in 15.2 g of pure ice.

The molar mass of [tex]H_{2}O[/tex] is 18g.

To calculate the number of moles of a substance in a given mass of the sample, we divide the given mass by the molar mass of the sample,

Number of moles = given mass / molar mass

It is given that we have 15.2g of pure ice. Then the number of moles of [tex]H_{2}O[/tex] will be:

n = 15.2/18

n = 0.84 moles.

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Answer:

–4020 KJ

Explanation:

The following data were obtained from the question:

H₂(g) + F₂(g) —> 2HF(g) ΔH = –536 KJ

Next, we shall determine the mass of H₂ that reacted from the balanced equation to produce –536 KJ of heat energy. This can be obtained as follow:

Molar mass of H₂ = 2 × 1 = 2 g/mol

Mass of H₂ from the balanced equation = 1 × 2 = 2 g.

Summary:

From the balanced equation above,

2 g of H₂ reacted to produce –536 KJ of heat energy.

Finally, we shall determine the heat change produced by the reaction of 15 g of H₂. This can be obtained as follow:

From the balanced equation above,

2 g of H₂ reacted to produce –536 KJ of heat energy.

Therefore, 15 g of H₂ will react to produce = (15 × –536)/2 = –4020 KJ of heat energy.

Thus, the heat change for the reaction is –4020 KJ

Answer:

Ground state means when n = 1

and here the electronic configuration is 2:8:2

Answer:

I put B&C

Explanation:

Answer:

12.3

Explanation:

Trust

Ideal gas law is valid only for ideal gas not for vanderwaal gas. Therefore, 12.3L is the volume of a balloon that contains a 1.00 mol sample of oxygen with a pressure of 2.00 atm at 300.0 K.

Ideal gas equation is the mathematical expression that relates pressure volume and temperature. There is no force of attraction between the particles.

Mathematically the relation between Pressure, volume and temperature can be given as

PV=nRT

where,

P = pressure of oxygen gas= 2.00 atm

V= volume of oxygen gas =?

n =number of moles of oxygen gas=1.00 mol

T =temperature of oxygen gas =300.0 K

R = Gas constant = 0.0821 L.atm/K.mol

Substituting all the given values, we get

2.00×V=1× 0.0821×300.0

On calculation we get

Volume=12.3L

Therefore, the volume of oxygen is 12.3L.

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Answer:

After the water has evaporated, the white crystals in the beaker have a mass of 20.0g.

The pieces of experimental evidence would best help the student to confirm that a new compound had not been made and that only a physical change occurred is of 20.0 g of white KCl crystals.

Physical changes are defined as a modification to a sample of material when some of the substance's attributes change but the composition of the sample remains the same. The digestion of food, combustion, osmosis, and phase transitions are just a few examples of how these changes play a crucial role in our daily lives.

Crystals are defined as a solid substance whose elements such as atoms, molecules, or ions are grouped in a highly organized microscopic structure to create an all-pervasive crystal lattice. Crystals are formed when molecules in a liquid group together to stabilize when it starts to cool and solidify.

Thus, the pieces of experimental evidence would best help the student to confirm that a new compound had not been made and that only a physical change occurred is of 20.0 g of white KCl crystals.

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The reactants react with oxygen and there is energy formed.

Answer:

6.624× 10²³ molecules      

Explanation:

Given data:

Mass of KOH = 60 g

Number of molecules = ?

Solution:

First of all we will calculate the number of moles.

Number of moles = mass/molar mass

Number of moles = 60 g/ 56.1 g/mol

Number of moles = 1.1 mol

Now number of molecules are determine by using Avogadro number.  

1 mole = 6.022 × 10²³ molecules

1.1 mol × 6.022 × 10²³ molecules / 1mol

6.624× 10²³ molecules        

Avogadro number:

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen

Answer:

no

Explanation:

Answer:

Gold is a relatively dense metal because its atoms have more

protons than atoms of many other metals.

Explanation:

The volume did not change, it remained at 20 ml

Given

20 ml a sample gas at STP(273 K, 1 atm)

T₂=546 K

P₂=2 atm

Required

The volume

Solution

Combined gas Law :

[tex]\tt \dfrac{P_1.V_1}{T_1}=\dfrac{P_2.V_2}{T_2}[/tex]

Input the value :

[tex]\tt \dfrac{1\times 20}{273}=\dfrac{2\times V_2}{546}\\\\V_2=\dfrac{1\times 20\times 546}{273\times 2}\\\\V_2=20~ml[/tex]

The volume does not change because the pressure and temperature are increased by the same ratio as the initial conditions (to 2x)

Anser:

Explanation:

hope this helps

Answer:

Engery is the driving force of the oxygen cycle is photosynthesis itself, which is responsible for the creation and maintenance of earth's atmosphere.Plants are able to use the energy of sunlight to convert carbon dioxide and water into carbohydrates and oxygen.

Answer:

Energy is the main force of the oxygen cycle and not to mention also photosynthesis, which is responsible for the creation of the earth's atmosphere. This would also mean that plants are the main focus of the Oxygen cycle and energy is needed to make plants. So without energy, no plants would exist!  Not to mention the oxygen cycle wouldn't work without energy.  Plants are also able to use the energy of sunlight to convert carbon dioxide and water into carbohydrates and oxygen.

Hope this helps! :)

Explanation:

Answer:

9.79740949850 moles

Explanation:

Side Note: Please let me know if you need any clarifications about this!

Answer:

c. fungi

Explanation:

Decomposers are organisms that breaks down dead and decaying matter in nature. They derived their nourishment by breaking down other complex organic matter.

Fungi are a group of organisms that are mainly decomposers.

They recyclers in nature.

Green plants and photosynthetic bacteria are similar in that they obtain nourishment by the use of light to initiate the reaction between carbon dioxide and water.

Many protists are decomposers but not all.