Which of the three crowns was made of gold? Explain:

Answer:

From the given equation, we can see that for every 2 moles of Al, we get 3 moles of H2

So, we can say the the number of moles of H2 is 3/2 times the number of moles of Al

We are given the number of moles of Al and we have to find the number of moles of H2

We have deduced the relationship:

Moles of Al * 3 / 2 = Moles of H2

Replacing the variables with given values

3.5 * 3 / 2 = Moles of H2

Moles of H2 = 5.25 moles

Answer:

The noble gases (Group 18) are located in the far right of the periodic table and were previously referred to as the "inert gases" due to the fact that their filled valence shells (octets) make them extremely nonreactive. The noble gases were characterized relatively late compared to other element groups.

The History

The first person to discover the noble gases was Henry Cavendish in the late 180th century. Cavendish distinguished these elements by chemically removing all oxygen and nitrogen from a container of air. The nitrogen was oxidized to  NO2  by electric discharges and absorbed by a sodium hydroxide solution. The remaining oxygen was then removed from the mixture with an absorber. The experiment revealed that 1/120 of the gas volume remained un-reacted in the receptacle. The second person to isolate, but not typify, them was William Francis (1855-1925). Francis noted the formation of gas while dissolving uranium minerals in acid.

Argon

In 1894, John William Strutt discovered that chemically-obtained pure nitrogen was less dense than the nitrogen isolated from air samples. From this breakthrough, he concluded that another, unknown gas was present in the air. With the aid of William Ramsay, Strutt managed to replicate and modify Cavendish's experiment to better understand the inert component of air in his original experiment. The researchers' procedure differed from the Cavendish procedure: they removed the oxygen by reacting it with copper, and removed the nitrogen in a reaction with magnesium. The remaining gas was properly characterized and the new element was named "argon," which originates from the Greek word for "inert."

Helium

Helium was first discovered in 1868, manifesting itself in the solar spectrum as a bright yellow line with a wavelength of 587.49 nanometers. This discovery was made by Pierre Jansen. Jansen initially assumed it was a sodium line. However, later studies by Sir William Ramsay (who isolated helium on Earth by treating a variety of rare elements with acids) confirmed that the bright yellow line from his experiment matched up with that in the spectrum of the sun. From this, British physicist William Crookes identified the element as helium.

Neon, Krypton, Xenon

These three noble gases were discovered by Morris W. Travers and Sir William Ramsay in 1898. Ramsay discovered neon by chilling a sample of the air to a liquid phase, warming the liquid, and capturing the gases as they boiled off. Krypton and xenon were also discovered through this process.

Radon

In 1900, while studying the decay chain of radium, Friedrich Earns Dorn discovered the last gas in Group 18: radon. In his experiments, Dorn noticed that radium compounds emanated radioactive gas. This gas was originally named niton after the Latin word for shining, "nitens". In 1923, the International Committee for Chemical Elements and International Union of Pure Applied Chemistry (IUPAC) decided to name the element radon. All isotopes of radon are radioactive. Radon-222 has the longest half-life at less than 4 days, and is an alpha-decay product of Radium-226 (part of the U-238 to Pb-206 radioactive decay chain).

The Electron Configurations for Noble Gases

Helium 1s2

Neon [He] 2s2 2p6

Argon [Ne] 3s2 3p6

Krypton [Ar] 3d10 4s2 4p6

Xenon [Kr] 4d10 5s2 5p6

Radon [Xe] 4f14 5d10 6s2 6p

Explanation:

Answer:

Oa. Weathering breaks down rocks; deposition leaves them in new places.

Explanation:

Did test and got it right.

Answer:

102.8 mL.

Explanation:

From the question given above, the following data were obtained:

Molarity of stock solution (M1) = 10.7 M

Molarity of diluted solution (M2) = 0.2 M

Volume of diluted solution (V2) = 5.5 L

Volume of stock solution needed (V1) =.?

The volume of the stock solution needed can be obtained by using the following formula:

M1V1 = M2V2

10.7 × V2 = 0.2 × 5.5

10.7 × V2 = 1.1

Divide both side by 10.7

V2 = 1.1 / 10.7

V2 = 0.1028 L

Finally, we shall convert 0.1028 L to millilitres (mL) in order to obtain the desired result. This can be obtained as follow:

1 L = 1000 mL

Therefore,

0.1028 L = 0.1028 L × 1000 mL / 1 L

0.1028 L = 102.8 mL

Therefore, 0.1028 L is equivalent to 102.8 mL.

Thus, 102.8 mL of the stock solution (i.e perchloric acid) is needed.

Answer:

Ca(ClO₃)₂(s)      →      CaCl₂(s) + 3O₂(g)

Explanation:

Chemical equation:

Ca(ClO₃)₂(s)      →      CaCl₂(s) + O₂(g)

Balance chemical equation:

Ca(ClO₃)₂(s)      →      CaCl₂(s) + 3O₂(g)

Step 1:

Ca(ClO₃)₂(s)      →      CaCl₂(s) + O₂(g)

Left hand side                     Right hand side

Ca = 1                                     Ca = 1

Cl = 2                                     Cl = 2

O =  6                                     O = 2

Step 2:

 Ca(ClO₃)₂(s)      →      CaCl₂(s) + 3O₂(g)

Left hand side                     Right hand side

Ca = 1                                     Ca = 1

Cl = 2                                     Cl = 2

O =  6                                     O = 6

Answer:

b- 4.4 * 10^-12.

Explanation:

Hello.

In this case, as the reaction:

A + 2B → 3C

Has an equilibrium expression of:

[tex]K_1=\frac{[C]^3}{[A][B]^2}=2.1x10^{-6}[/tex]

If we analyze the reaction:

2A + 4B → 6C

Which is twice the initial one, the equilibrium expression is:

[tex]K_2=\frac{[C]^6}{[A]^2[B]^4}[/tex]

It means that the equilibrium constant of the second reaction is equal to the equilibrium constant of the first reaction powered to second power:

[tex]K_2=K_1^2[/tex]

Thus, the equilibrium constant of the second reaction turns out:

[tex]K_2=(2.1 * 10^{-6})^2\\\\K_2=4.4x10^{-12}[/tex]

Therefore, the answer is b- 4.4 * 10^-12.

Best regards.

Answer:

Hydrogen gas (H2) is a molecule, but not a compound because it is made of only one element. Water (H2O) can be called a molecule or a compound because it is made of hydrogen (H) and oxygen (O) atoms. There are two main types of chemical bonds that hold atoms together: covalent and ionic/electrovalent bonds.

Answer:

see images attached

Explanation:

Here we are trying to perform solvent extraction. In solvent extraction, there must be an aqueous phase and an organic phase.

One of the species to be separated is extracted in greater concentration in the aqueous phase while the other is extracted in greater concentration in the organic phase.

The phase into which each specie is extracted depends on the nature of the specie.

Two structures are shown in the images attached that will be separated by the methods shown in (a) (b) (c) in the question

Answer:

a) increases

b) decreases

c) does not change

d) increases

Explanation:

The vapour pressure of a liquid is dependent on;

I) the magnitude of intermolecular forces

II) the temperature of the liquid

Hence, when any of these increases, the vapour pressure increases likewise.

Similarly, the boiling point of a liquid depends on the magnitude of intermolecular forces present because as intermolecular forces increases, more energy is required to break intermolecular bonds.

Lastly, increase in surface area of a liquid does not really affect it's vapour pressure.

Answer:

It's called Evaporation.

Answer:

A hurricane can cause extreme damage to the biosphere and the geosphere. A hurricane can leave water standing therefore sinking itself into the geosphere. The biosphere can be permanently effected because it can kill, injure, and destroy the biosphere and what the biosphere creates (buildings, parks).

Explanation:

Answer:

its natural gas because i had something like this

Explanation:

The renewable energy sources, such as biomass, geothermal resources, water, wind, etc. are called the natural resources. These can be converted into clean and usable energy. The correct option is D.

The energy which is derived from the natural sources which are replenished at a higher rate than they are consumed is defined as the Renewable energy. The renewable energy generating produce lower emissions than burning the fossil fuels.

The word biomass refers to the organic plant matter which is converted into fuel and used as an energy source. The biomass fuel is considered as an important renewable and sustainable source of energy. It is used for the production of electricity.

The organic materials like wood, agricultural wastes, etc. acts as the excellent sources to produce biomass fuel. It is possible to burn the biomass fuel directly and later converted into methane and ethanol biofuels.

Thus the correct option is D.

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Answer:

b is the correct answer

do not trust answer one

Explanation:

Answer:

[tex]Total = 50.6\ moles[/tex]

Explanation:

Given

[tex]Propane = C_3H_8[/tex]

Represent Carbon with C and Hydrogen with H

[tex]C = 13.8[/tex]

Required

Determine the total moles

First, we need to represent propane as a ratio

[tex]C_3H_8[/tex] implies

[tex]C:H = 3:8[/tex]

So, we're to first solve for H when [tex]C = 13.8[/tex]

Substitute 13.8 for C

[tex]13.8 : H = 3 : 8[/tex]

Convert to fraction

[tex]\frac{13.8}{H} = \frac{3}{8}[/tex]

Cross Multiply

[tex]3 * H = 13.8 * 8[/tex]

[tex]3 H = 110.4[/tex]

Solve for H

[tex]H = 110.4/3[/tex]

[tex]H = 36.8[/tex]

So, when

[tex]C = 13.8[/tex]

[tex]H = 36.8[/tex]

[tex]Total = C + H[/tex]

[tex]Total = 13.8 + 36.8[/tex]

[tex]Total = 50.6\ moles[/tex]

Answer:

Explanation:

In order to find out the final temperature we use the formula for Charles's law which is

[tex] \frac{V_1}{T_1} = \frac{V_2}{T_2} \\ [/tex]

where

V1 is the initial volume

T1 is the initial temperature in Kelvin

V2 is the final volume

T2 is the final temperature in Kelvin

Since we are finding the final temperature

[tex]T_2 = \frac{V_2T_1}{V_1} \\ [/tex]

rom the question

V1 = 5.5 L

T1 = -38°C = -38 + 273 = 235 K

V2 = 1.30 L

We have

[tex]T_2 = \frac{1.30 \times 235}{5.5} = \frac{305.5}{5.5} \\ = 55.545454...[/tex]

We have the final answer as

Hope this helps you

Answer:

The correct answer is 146 g/mol

Explanation:

Freezing point depression is a colligative property related to the number of particles of solute dissolved in a solvent. It is given by:

ΔTf = Kf x m

Where ΔTf is the freezing point depression (in ºC), Kf is a constant for the solvent and m is the molality of solution. From the problem, we know the following data:

ΔTf = 1.02ºC

Kf = 5.12ºC/m

From this, we can calculate the molality:

m = ΔTf/Kf = 1.02ºC/(5.12ºC/m)= 0.199 m

The molality of a solution is defined as the moles of solute per kg of solvent. Thus, we can multiply the molality by the mass of solvent in kg (250 g= 0.25 kg) to obtain the moles of solute:

0.199 mol/kg benzene x 0.25 kg = 0.0498 moles solute

There are 0.0498 moles of solute dissolved in the solution. To calculate the molar mass of the solute, we divide the mass (7.27 g) into the moles:

molar mass = mass/mol = 7.27 g/(0.0498 mol) = 145.9 g/mol ≅ 146 g/mol

Therefore, the molar mass of the compound is 146 g/mol

Answer:

Proton or electron. I think, not sure.

Explanation:

A proton and an electron have an equal amount but an opposite type of charge. Thus, if an atom contains equal numbers of protons and electrons, the atom is described as being electrically neutral.

eletrons I'm pretty sure

Answer: 6

Explanation:

Answer:

this atom has nine electrons

Answer:

Mass = 42.6 g

Explanation:

Given data:

Mass of CF₂Cl₂ = 31.2 g

Mass of Cl₂ = ?

Solution:

Number of moles of CF₂Cl₂ = mass/molar mass

Number of moles =  31.2 g/121 gmol

Number of moles = 0.3  mol

1 mole of CF₂Cl₂ contain 2 moles of Cl atom.

0.3 mol × 2 = 0.6 mol

Mass of Cl₂:

Mass = number of moles × molar mass

Mass = 0.6 mol × 71 g/mol

Mass = 42.6 g

Answer:

zirconium is Zr

rhenium is Re

As is arsenic

K is potassium

tin is Sn

yttrium is Y

ytterbium is Yb

Explanation:

With the help of the periodic table, the identification of the chemical symbol or name for each element is represented as follows:

Chemical elements may be defined as any type of substance that cannot be further decomposed into simpler substances through the utilization of other ordinary chemical processes or external factors. These elements possess specific physical as well as chemical properties distinctly.

In the modern periodic table, each element is arranged on the basis of its increasing atomic number. Each element possesses its unique symbol, atomic mass, and physical properties like boiling points, melting points, density, etc.

Therefore, with the help of the periodic table, the identification of the chemical symbol or name for each element is well represented above.

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Answer:

1.     CaCO3 + 2HCl → CaCl2 + H2O + CO2

2.    C6H12O2 + 8O2 → 6CO2 + 6H2O

Explanation:

The balanced chemical equation is (i) CaCO3+2HCl⟶CaCl2+CO2+H2O

(ii) C6H12O2+ 8O2⟶CO2+6H2O

An equation with equal amounts of every atom of an element on both endpoints of the arrow was called a balanced equation.

Given chemical equation is:

(i) CaCO3+HCl⟶CaCl2+CO2+H2O

It can be seen that in left side of the chemical equation count of chlorine atom is one while right side of the chemical equation it is two. So, by multiplying 2 as a coefficient in the right side of the equation. Balanced chemical equation will be

CaCO3+2HCl⟶CaCl2+CO2+H2O

(ii) C6H12O2+O2⟶CO2+H2O

It can be seen that, there are 12 hydrogen in the left side of the reaction while it is two hydrogen in the right side of the reaction. By multiplying 6 as a coefficient of hydrogen. Hence, the balanced chemical equation will be

C6H12O2+ 8O2⟶CO2+6H2O

The balanced chemical equation is

(i) CaCO3+2HCl⟶CaCl2+CO2+H2O

(ii) C6H12O2+ 8O2⟶CO2+6H2O

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Answer:

The equilibrium constant change. For an endothermic reaction, heat is a reactant. An increase in temperature and heat favors the forward reaction and the value of Kc increases.

Explanation:

Hello.

In this case, regarding reactions in equilibrium in which heat is a reactant as those exemplified by:

[tex]Heat+Reactants \rightleftharpoons Products[/tex]

We infer that the heat of reaction is positive since the reactants have more energy in their ground state than the products making them endothermic. Moreover, since the Le' Chatelier's principle states that increasing the reaction temperature in endothermic reactions, the forward reaction (towards products) is favored because endothermic reactions absorb heat in the form temperature raise, the required statement is:

The equilibrium constant change. For an endothermic reaction, heat is a reactant. An increase in temperature and heat favors the forward reaction and the value of Kc increases.

Regards.

Answer:

The equilibrium constant increases. For an endothermic reaction heat is a reactant. An increase in temperature and heat favours the forward reaction and the value of KC increases.

Explanation:

Answer:

H2O

Explanation:

The equation for the decomposition of hydrogen peroxide is shown below;

2H2O2(l)-----> 2H2O(l) + O2(g)

Hence, the decomposition of H2O2 yields oxygen gas and water. Water is a non gaseous product of the reaction as clearly seen in the equation above.

Answer:

9000 pounds

Explanation:

9000 pounds

Answer: 9000 lbs.

Explanation: 4.5 tons = 9000 pounds.

Answer:

Modern periodic law

Explanation:

There are many ways of stating the modern periodic law. Generally, the modern periodic law states that the properties of elements are a periodic function of their atomic numbers. That means, similar properties recur periodically when elements are arranged according to increasing atomic number.

Two scientists were largely responsible for our present day understanding of the modern periodic law, they are, Mendeleev and Moseley. Their work laid the foundation for the periodic table in its current form.

Answer:

2.00g/ml

Explanation:

If water has a density of 1.00g/ml, and theres

40ml of it, it would weigh 40g

The substance is twice as dense as water, making its density 2.00g/ml