A penny has a thickness of approximately 1.0 mm. If you stacked Avogadro's number of pennies one on top of the other on Earth's surface, how far would the stack extend (in kilometers). For comparison, the sun is about 150 million km from Earth and the nearest star (Proxima Centauri) is about 40 trillion km from Earth].

Answer:

Kc = 0.630

Explanation:

The equilibrium of the thiocyanate system occurs as follows:

FeSCN²⁺(aq) ⇄ Fe³⁺(aq) + SCN⁻(aq)

And equilibrium constant, kc, is:

Kc = [SCN⁻] [Fe³⁺] / [FeSCN²⁺]

Replacing with the gven concentrations:

Kc = 0.639M*0.494M / 0.501M

Answer:

See explanation

Explanation:

The atomic number refers to the number of protons in the nucleus, it also tells us the number of electrons in the neutral atom since the atom is electrically neutral because the number of protons and electrons are equal.

If an atom has the atomic number 11, then the electrons in the atom are arranged in the shells in the order; 2, 8, 1.

Two electrons are found in the innermost shell, eight electrons are found in the next shell and one electron is found on the outermost shell.

The nucleus of the atom is composed of a total of 23 nucleons; 11 protons and 12 neutrons.

Answer:

Kf = 0.389.

Explanation:

Hello there!

In this case, it turns out possible for us to solve this problem by firstly writing the equilibrium chemical equation and equilibrium expression for the formation of this complex:

[tex]B+C\rightleftharpoons BC\\\\Kf=\frac{[BC]}{[B][C]}[/tex]

Thus, we firstly calculate the concentrations at equilibrium, knowing that the reaction extent in this case is 0.00500mol (same as the formed moles of BC):

[tex][B]=[C]=\frac{0.0350L*1.00mol/L-0.00500mol}{0.0700L} =0.429M[/tex]

[tex][BC]=\frac{0.00500mol}{0.0700L} =0.0714M[/tex]

And finally, the equilibrium constant:

[tex]Kf=\frac{0.0714}{[0.429][0.429]}\\\\Kf=0.389[/tex]

Regards!

The question is incomplete, the complete question is:

A certain liquid X has a normal freezing point of [tex]0.80^oC[/tex] and a freezing point depression constant [tex]K_f=7.82^oC.kg/mol[/tex] . Calculate the freezing point of a solution made of 81.1 g of iron(III) chloride () dissolved in 850. g of X. Round your answer to significant digits.

Answer: The freezing point of the solution is [tex]-17.6^oC[/tex]

Explanation:

Depression in the freezing point is defined as the difference between the freezing point of the pure solvent and the freezing point of the solution.

The expression for the calculation of depression in freezing point is:

[tex]\text{Freezing point of pure solvent}-\text{freezing point of solution}=i\times K_f\times m[/tex]

OR

[tex]\text{Freezing point of pure solvent}-\text{Freezing point of solution}=i\times K_f\times \frac{m_{solute}\times 1000}{M_{solute}\times w_{solvent}\text{(in g)}}[/tex] ......(1)

where,

Freezing point of pure solvent = [tex]0.80^oC[/tex]

Freezing point of solution = [tex]?^oC[/tex]

i = Vant Hoff factor = 4 (for iron (III) chloride as 4 ions are produced in the reaction)

[tex]K_f[/tex] = freezing point depression constant = [tex]7.82^oC/m[/tex]

[tex]m_{solute}[/tex] = Given mass of solute (iron (III) chloride) = 81.1 g

[tex]M_{solute}[/tex] = Molar mass of solute (iron (III) chloride) = 162.2 g/mol

[tex]w_{solvent}[/tex] = Mass of solvent (X) = 850. g

Putting values in equation 1, we get:

[tex]0.8-(\text{Freezing point of solution})=4\times 7.82\times \frac{81.1\times 1000}{162.2\times 850}\\\\\text{Freezing point of solution}=[0.8-18.4]^oC\\\\\text{Freezing point of solution}=-17.6^oC[/tex]

Hence, the freezing point of the solution is [tex]-17.6^oC[/tex]

Answer:

Boiled a added acidic solution for Lowe's home improvement for car insurance cost the Africa map of the soul

Answer:

climate change

Explanation:

climate change is driving force of evolution because when the climate is changed the animal and human need to adapt to it's natural change.

the identity of element remains same

Answer:

Give the IUPAC name for the following alkyl group, and classify it as primary, secondary, or tertiary.

CH3(CH2)9CH2

Explanation:

In the given alkyl group there are eleven carbon atoms.

So, the alkyl group name is:

n-undecyl.

Pimary carbon is the one which is attached only one other carbon atom,group.

Secondary carbon is the one which is attached to two carbons.

Thertiary carbon is the one which is attached to three other carbons.

In the given alkyl group,

the primary,secondary alkyl groups are shown below:

There is no tertiary carbon atom in the given molecule.

Answer:

The same number of each atom are on both sides of the equation.

The Law of conservation of mass states that matter is neither destroyed nor created in a chemical reaction. Therefore, the mass of the reactants will be equal to the mass of the products in a chemical reaction. According to the law matter is neither created nor destroyed in a chemical reaction.

Answer:

anemometer

Explanation:

The instrument that is being described is called an anemometer. This is a device that has 4 ladel like objects that allow the wind to hit it, causing it to spin. The force of the spin allows meteorologists to calculate the speed of the wind. On top of this device is usually an arrow which can rotate around the device with the wind and point in the direction that the wind is blowing. Using a N, NE, E, SE, S, SW, W, and NW direction.

Answer: The ion that contribute to water hardness are:

--> a. Ca2+

--> b. (HCO)3^- and

--> c. Mg2+

While K+ DOES NOT contribute to water hardness.

Explanation:

WATER in chemistry is known as a universal solvent. This is so because it is polar in nature and dissolves most inorganic solutes and some polar organic solutes to form aqueous solutions. It is composed of elements such as hydrogen and oxygen in the combined ratio of 2:1.

Water is said to be HARD if it does not lather readily with soap. There are two types of water hardness:

--> Permanent hardness: This is mainly due to the presence of CALCIUM and MAGNESIUM ions in the form of soluble tetraoxosulphate(VI) and chlorides. These ions are removed by adding washing soda or caustic soda.

--> Temporary hardness: This is due to the presence of calcium HYDROGENTRIOXOCARBONATES. It can be removed by boiling and using slaked lime.

Therefore from the above given ions, Ca2+,(HCO)3^- and Mg2+ contributes to water hardness.

Answer:

1. Granite

2. 535.5J

Explanation:

1. The lower the specific heat capacity of a substance, which is the amount of heat needed to raise the temperature of a particular mass of substance by 1 °C or K, the slower the rate at which the temperature is raised.

In this question 1, the substance with the lowest specific heat capacity in J/gK is GRANITE, hence, it will raise temperature the slowest.

2. Using the formula as follows:

Q = m × c × ∆T

Where;

c = specific heat capacity

Q = amount of heat (J)

m = mass of substance

∆T = change in temperature (°C)

m = 35g, c = 0.45 J/g°C, ∆T = 54°C - 20°C = 34°C

Q = 35 × 0.45 × 34

Q = 535.5J

Answer:

See explanation and image attached

Explanation:

Nitrogen trichloride NCl3 contains one nitrogen and three chlorine atoms. Each chlorine atom has three lone pairs of electrons while nitrogen has one lone pair of electrons.

The molecule geometry of the molecule is trigonal pyramidal while it's electron domain geometry is tetrahedral. Nitrogen is the central atom and is found in sp3 hybridization.

There is no formal charge on the molecule.

Answer:

See explanation and image attached

Explanation:

Grignard reagent is any organic compound that is classified as an alkyl or aryl magnesium halide (RMgX).

Grignard reagents are produced when the alkyl halide reacts with magnesium metal in ether and tetrahydrofuran as solvents.

They are good nucleophiles and are involved in the synthetic routes to many important classes of organic compounds.

The formation of Grignard reagent from bromobenzene is shown in the image attached to this answer.

Answer:

molar mass of copper = 63.55 g/mol

( 1 mol of copper)

6.19 g copper × ( 63.55g copper )

0.0975 moles

Answer: C

Explanation:

Answer:

Mass number (A) is the number of nucleons (proton and neutron) present in a atom.

Explanation:

electrons don't cout since they are thousandth's of the mass of protons or neutrons

Answer:

The fuse is a thin wire that is the conductor of electricity is designed to breaks the circuit if there is a fault in an appliance that causes excessive current to flow in a circuit.

The conductor used in the fuse is melt and separated in such cases of excessive current in a circuit and switch the current off.

A circuit breaker is made up of a thin wire that is specially designed to switch that automatically breaks circuit current in the overcurrent condition.

Answer:

Calcium Oxide is a drying agent, hence it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.

It preferred to use calcium oxide rather than calcium chloride in preparation of iron (III) chloride because Calcium Oxide is a drying agent, hence it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.

A process such as a chemical reaction that removes water.The atoms which constitute the molecule of water that is removed.

Hence,It preferred to use calcium oxide rather than calcium chloride in preparation of iron (III) chloride because Calcium Oxide is a drying agent,

Thus, it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.

Learn  more about reactions here ;

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Answer:

i think C  is the answer

Explanation:

The change in average annual temperatures on earth will be due to "photosynthesis by plants and algae".

Photosynthesis can be defined as a process in which plants, as well as other organisms, as well as other organisms, utilize to transform sunlight into chemical energy which can then be released to power the organism's activities using cellular respiration.

Plants seem to be mostly photosynthetic eukaryotes belonging to the plantae kingdom.

Therefore, photosynthesis cannot change in average annual temperature on Earth.

To know more about photosynthesis.

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Answer:

A solution contains 100mM NaCl, 20mM CaCl2, and 20mM urea. We would say this solution is hypotonic compared to a 300 mOsM solution and hypotonic compared to a cell with 300 mOsM (non-penetrating solutes) interior.

Explanation:

The osmolarity is calculated from the molar concentration of the active particles in the solution. We have a solution that is composed of NaCl, CaCl₂ and urea.

When they are dissolved in water, they dissociate into particles as follows:

NaCl → Na⁺ + Cl⁻  (2 particles per compound)

CaCl₂ → Ca²⁺ + 2 Cl⁻ (3 particles per compound)

urea: not dissociation (1 particle per compound)

Then, we have to calculate the osmolarity of the solution. We multiply the molarity of each compound by the number of particles produced by the compound in water:

Osm = (100 mM NaCl x 2) + (20 mM CaCl₂ x 3) + (20 mM urea x 1) = 280 mOsm

Compared with 300 mOsm, 280 mOsm has a lower osmolarity, so it is a hypotonic solution.

To compare with a cell's osmolarity, we have to consider only the non-penetrating solutes. Urea is considered a penetrating solute for mammalian cells. So, the osmolarity of non-penetrating solutes (NaCl  and CaCl₂) is calculated as:

Osm (non-penetrating solutes) = (100 mM NaCl x 2) + (20 mM CaCl₂ x 3) = 260 mOsm

Therefore, we have:

Compared to 300 mOsm solution ⇒ 280 mOsm solution is a hypotonic solution

Compared to a cell with 300 mOsm ⇒ 260 mOsm solution is hypotonic

Answer:

A 1 liter volumetric flask should be used.

Explanation:

First we convert 166.00 g of KI into moles, using its molar mass:

Molar mass of KI = Molar mass of K + Molar mass of I = 166 g/mol

Then we calculate the required volume, using the definition of molarity:

Liters = moles / molarity

Answer:

0.0457 M

Explanation:

Concentration is the amount of a substance in a predefined volume of space. The basic measurement of concentration in chemistry is molarity or the number of moles of solute per liter of solution. What is the molarity of a solution containing 9.478 grams of RuCl₃, in enough water to make 1.00 L of solution?

Step 1: Given data

Step 2: Calculate the moles corresponding to 9.478 g of RuCl₃

The molar mass of RuCl₃ is 207.4 g/mol.

9.478 g × 1 mol/207.4 g = 0.04570 mol

Step 3: Calculate the molarity of the solution

We will use the definition of molarity.

M = moles of solute / liters of solution

M = 0.04570 mol / 1.00 L = 0.0457 M

Answer:

Ethanal or acetaldehyde

Explanation:

Ethanal, also called acetaldehyde is the second member of the alkanal or aldehyde group of hydrocarbons, which have a functional group of -CHO. The -CHO functional group characterizes every member to this group and makes them behave chemically similar.

However, the second member of this aldehyde group with a formula of CH3----CHO, has a methyl group (CH3) attached to the functional group, hence, it is called ETHANAL OR ACETALDEHYDE.

Answer:

mwlooy kagabi jal

64 JAHA VI PHÂN KAY

Answer:

Water forms more hydrogen bonds than HF

Explanation:

The answer to this question goes back to the idea of hydrogen bonding. Hydrogen bonding occurs when hydrogen is bonded to a highly electronegative atom such as fluorine or oxygen.

However, in HF, there are three lone pairs of electrons on fluorine atom and one hydrogen atom bonded to fluorine.

In H2O, there are two lone pairs of electrons on oxygen atom and two hydrogen atoms bonded to oxygen. This simply means that water can form four hydrogen bonds while HF only forms two hydrogen bonds.

This implies that H2O molecules possess more hydrogen bonding than HF molecules. Hence, the molar enthalpy of vaporization for liquid hydrogen fluoride is lesser than that for water.

Answer:

a. 3-brumo - 3-methylhexane

Explanation:

Alkyl Halides can undergo substitution reactions. Nucleophiles are electron rich species and has negative charge while Electrophiles are electron deficient species which carry positive charge. Alkyl halide which have polar carbon atom are electrophiles.