If two atoms are the same element, which statement can never be true?

1: they can have different number of protons.

2:they can have different number of electrons.

3:they can have different number of neutrons

Answer:

1.-213(kcal/mol)*5mol=1065kcal

2.100/213 mol

a. The energy released from 5.0 mol of methane is -1065 kcal/mol.

b. The number of moles of methane needed to give 100. kcal heat is 0.4694 moles.

Combustion is a chemical process in which the element reacts with oxygen to produce heat and light. Burning of wood.

The equation of combustion of methane:

CH₄ (g) + 2O₂(g) ------> CO₂ (g) + 2H₂O (l)

a) Enthalpy of the reaction is H = -213 Kcal/mol

This means 213 Kcal heat is released in the burning of one mole of CH4

H reaction = [ H products ] - [ H reactants ]

Hr = [ H(CO₂)g + 2H(H₂O)l ] - [ H(CH₄)g ] = -213 kcal/mol

For 5 moles of methane:

5CH₄(g) + 10O₂(g) -----> 5CO₂(g) + 10H₂O(l)

therefore, new Hr = 5 x -213 = -1065 kcal/mol

H reaction = -1065 kcal/mol

b) 213 kcal is released per mole of Methane

then, to release 100 kcal we need, 100 / (213) = 0.4694 moles

Thus, the energy released is -1065 kcal/mol, and the number of moles is 0.4694 moles.

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food moves through the mouth by muscle movement

Answer:

CH₃CH₂CH₂COOH.

Explanation:

To know which option is correct, let us hydrolysed the given ester. This is illustrated in the attached photo.

Hydrolysis of ester involves breaking the ester bond by a water molecule to produce the corresponding alcohol and carboxylic acid.

From the reaction given in the attached photo, we can see that the carboxylic acid needed to produce the desired ester is butanoic acid, CH₃CH₂CH₂COOH.

Answer:

So... for the element of SODIUM, you already know that the atomic number tells you the number of electrons. That means there are 11 electrons in a sodium atom. Looking at the picture, you can see there are two electrons in shell one, eight in shell two, and only one in shell three.

Explanation:

brainliest pleaseeee <3

Answer:

so there would be 2 electrons because

Explanation:

sodium has 11 electrons but if you look at the shels it onl has one electron (from the image im looking at) and the other shell only have one so theres 2 electrons

Answer:

It has the atomic mass of 12.

Answer:

The magnification of the microscope is equal to the magnification of the ocular lens times the magnification of the objective lens. Since the objective lens has 10x printed on them at "low power". The total magnification would be 10 times 10.

Explanation:

i hope this helps C:

Answer:

I think the answer is B :)

Answer:

the first step is B

Explanation: I'm on this lesson

Answer:

D = 2.9 g/mL

Explanation:

Density = Mass over Volume

D = m/V

Step 1: Define

m = 58 g

V = 20 mL

D = unknown

Step 2: Substitute and Evaluate for Density

D = 58 g/20 mL

D = 2.9 g/mL

Answer: i would do the mineral formed when a hot water solution cooled because you said that a mineral forms in water heated by magma inside Earth.

Explanation:

The answer would be C

Explanation:

When magma cools down it will change into a rock type so the answer would be C.

Answer:

The Answer would be A. April

Explanation:

Least amount of rainfall out of all the months we have to choose from.

Answer:

Principle quantum number.

Explanation:

Answer:

a compound

Explanation:

lead has more metallic properties

The question is incomplete; the complete question is;

If the pressure of each gas is increased at constant temperature until condensation occurs, which gas will condense at the lowest pressure?

A) Octane

B) Ethane

C) Butane

D) All the gases will condense at the same pressure

Answer:

Octane

Explanation:

If we study the table closely we will realize that octane has the greatest molecular mass among all the gases shown.

The greater the molecular mass, the lower the pressure required for the condensation of the gas. Hence, the lowest pressure is required for the condensation of octane at constant temperature.

Answer:

Rock

Step-by-step explanation:

It's an igneous rock

I hope this helps!

Answer:

chemical properties can only be measured only by changing a substance chemical identity

Explanation:

apex

Answer:

The number of energy levels increases as you move down a group as the number of electrons increases. Each subsequent energy level is further from the nucleus than the last. Therefore, the atomic radius increases as the group and energy levels increase. 2) As you move across a period, atomic radius decreases.

Explanation:

Answer:

[tex]Excess=3.53g[/tex]

Explanation:

Hello,

In this case, the undergoing chemical reaction is:

[tex]2Mg(s)+O_2(g) \rightarrow 2MgO(s)[/tex]

Next, we identify the limiting reactant by computing the moles of magnesium oxide yielded by 3.86 g of magnesium and 155 mL of oxygen at the given conditions via their 2:1:2 mole ratios and the ideal gas equation:

[tex]n_{MnO}^{by \ Mg}=3.86gMg*\frac{1molMg}{24.3gMg}*\frac{2molMgO}{2molMg} =0.159molMgO\\\\n_{MnO}^{by \ O_2}=\frac{1atm*0.155L}{0.082\frac{atm*L}{molO_2*K}*275K} *\frac{2mol MgO}{1molO_2} =0.0137molMgO[/tex]

It means that the limiting reactant is the oxygen as it yields the smallest amount of magnesium oxide. Next, we compute the mass of magnesium consumed the oxygen only:

[tex]m_{Mg}^{consumed}=0.0137molMgO*\frac{2molMg}{2molMgO} *\frac{24.3gMg}{1molMg} =0.334gMg[/tex]

Thus, the mass in excess is:

[tex]Excess=3.86g-0.334g\\\\Excess=3.53g[/tex]

Regards!

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.

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Answer:

Compound

Explanation:

Answer:

Explanation:

The density of a substance can be found by using the formula

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

From the question

mass = 30.5 g

volume = 5 cm³

We have

[tex]density = \frac{30.5}{5} \\ [/tex]

We have the final answer as

Hope this helps you

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.

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Answer:

Chemical changes in compounds happen when chemical bonds are created or destroyed. Then the molecular structure changes; new molecules form and a new substance is created. Often heat is used to begin a chemical change, as when baking a cake. Another example of a chemical reaction is the rusting of a metal trash can.

An element is constituted of only atoms and no other entities are present in it. Whereas a chemical compound is a substance made up of various identical molecules of the same or different atoms.

The atoms of the same or different species bond together to form a compound.

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would be your answer because it releases other cells out and causes the needy of cells to evaporate and sink.

sublimation is the phase transition do molecules move directly from a state involving vibration of particles in a fixed position to a state involving random movement of high-speed particles.

In the process of printing sublimation shirts, an image is first printed on a special sheet of paper before being transferred to a different material, typically polyester or a polyester blend. After that, heat is applied to the ink until it fuses with the fabric.

Sublimation shirt printing is more expensive than other procedures, but it produces shirts that stay longer and don't peel or crack over time.

he primary distinction between sublimation and heat transfer is that during sublimation, just the ink transfers to the substrate. A transfer layer is frequently also transferred to the material during the heat transfer procedure.

Therefore, sublimation is the phase transition do molecules move directly from a state involving vibration of particles in a fixed position to a state involving random movement of high-speed particles.

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Answer:

Electron cloud

Explanation: