A chemist prepares a solution of magnesium fluoride MgF2 by measuring out 0.0113μmol of magnesium fluoride into a 450.mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in /mmolL of the chemist's magnesium fluoride solution. Round your answer to 3 significant digits.

Given :

12.9 mol of Au.

To Find :

How many atoms are in 12.9 moles Au.

Solution :

We know, 1 mol of any element/molecules contains [tex]6.022\times 10^{23}\ atoms/mol[/tex].

Number of atoms in 12.9 moles of Au is :

[tex]n = 12.9 \times 6.022\times 10^{23}\ atoms\\\\n = 7.77\times 10^{24}\ atoms[/tex]

Therefore, number of atoms in 12.9 moles of Au is [tex]7.77\times 10^{24}\ atoms[/tex].

Hence, this is the required solution.

Answer:

amy what happen to your old account and the answer is c

Explanation:

Answer:  Btu, British Thermal Unit is used to express thermal energy when working in pounds and degrees Farenheit.

Calories are used when working in grams and degrees Centigrade or Kelvin (SI units)

A Joule is the British system unit used to measure heat transfer.

Explanation:

Answer:

[tex]0.192\ \text{M}[/tex]

Explanation:

A = Absorbance of solution

E = Molar absorptivity

l = Length of cuvette = 1 cm

c = Concentration of solution

Beer's law is given by

[tex]A=Elc[/tex]

The equation of a straight line is given by

[tex]y=mx+c[/tex]

Comparing the above equations we get

Value on [tex]y[/tex] axis = A = Absorbance of solution = 0.23

[tex]m[/tex] = Slope of line = El = Molar absorptivity multiplied with length = [tex]1.2\times 1\ \text{M}^{-1}[/tex]

[tex]x[/tex] = Value of x axis = c = Concentration of solution

So we get

[tex]c=\dfrac{A}{El}\\\Rightarrow c=\dfrac{0.23}{1.2\times 1}\\\Rightarrow c=0.192\ \text{M}[/tex]

The molar concentration of the sample is [tex]0.192\ \text{M}[/tex]

Answer:

20 Neutrons

Explanation:

The element of potassium has the symbol K. The nucleus of an atom of potassium contains 19 protons and 20 neutrons. I hope that answer helps xx

Answer:

26.981539 u

Explanation:

Answer:

b) 4

Explanation:

The electron transport chain may be defined as the series of the complexes which transfer the electrons from electron donors to the electron acceptors through a redox reactions, and also couples the electron transfer along with the transfer of the protons across the membrane.

The electron transport chain or the ETC is made up of peptides and enzymes, and some other molecules.

The full form of ATP is Adenosine triphosphate. It is a chemical compound that provides energy to the living cells.

From one run in the ETC or the electron transport chain, 4 ATP can be generated.

Answer: 234.8 M

Explanation:

Answer:

Option D. 53 moles.

Explanation:

The following data were obtained from the question:

Number of mole of C5H10O2 = 5.3 moles

Number of mole of Hydrogen in 5.3 moles of C5H10O2 =?

From the chemical formula of propyl acetate, C5H10O2,

1 mole of C5H10O2 contains 10 moles of H.

Therefore, 5.3 moles of C5H10O2 will contain = 5.3 × 10 = 53 moles of H.

Thus, 5.3 moles of C5H10O2 contains 53 moles of H.

Answer:

it is calcium. it is in group(llA).

Answer:

hope it is helpful to you

Answer:

A) Sample B has more calcium carbonate molecules

Explanation:

M = Molar mass of calcium carbonate = 100.0869 g/mol

[tex]N_A[/tex] = Avogadro's number = [tex]6.022\times 10^{23}\ \text{mol}^{-1}[/tex]

For the 4.12 g sample

Moles of a substance is given by

[tex]n=\dfrac{m}{M}\\\Rightarrow n=\dfrac{4.12}{100.0869}\\\Rightarrow n=0.0411\ \text{mol}[/tex]

Number of molecules is given by

[tex]nN_A=0.0411\times 6.022\times 10^{23}=2.48\times 10^{22}\ \text{molecules}[/tex]

For the 19.37 g sample

[tex]n=\dfrac{19.37}{100.0869}\\\Rightarrow n=0.193\ \text{mol}[/tex]

Number of molecules is given by

[tex]nN_A=0.193\times 6.022\times 10^{23}=1.16\times 10^{23}\ \text{molecules}[/tex]

[tex]1.16\times 10^{23}\ \text{molecules}>2.48\times 10^{22}\ \text{molecules}[/tex]

So, sample B has more calcium carbonate molecules.

The ratio of the elements of carbon, oxygen, calcium atoms, ions, has to be same in both the samples otherwise the samples cannot be considered as calcium carbonate. Same is applicable for impurities. If there are impurites then the sample cannot be considered as calcium carbonate.

Answer:it's D

Explanation:

A chemical change, unlike a physical change, is the formation of new products or one or more new substances formed from the reactants. Thus, option D is correct.

A chemical change is a type of change where the reactants break or combine to form a new product that is different from the reactants. Unlike physical change, they are not reversible and can be seen in combustion, neutralization, decomposition, redox reactions, etc.

It is a change in a matter where the reactant undergoes breaking or forming of the bonds to yield a new product. It is accompanied by changes in temperature, color, precipitation, and odor.

Therefore, a chemical change results in the formation of a new substance.

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Answer:

B

Explanation:

bshdiidididjdjjdididid

Answer:

the given reaction after balancing is:

4Ag + 2H2S +O2 > 2AG2S +2H2O

Explanation:

4Ag=Ag

2H2=2H2

O2=20

2S=2S

I hope that you will understand that.

The question is incomplete, the complete question is shown in the image attached

Answer:

F

T

Explanation:

From the equilibrium equation;

N2O4(g) ⇄NO2(g)

We must have to remember that;

1) At equilibrium, the concentration of the species on both sides of the reaction equation may not necessarily be the same but must be held at a constant value because the rate of forward reaction equals the rate of reverse reaction.

2) The rate of forward reaction must equal the rate of reverse reaction.

If the rate of forward reaction is k1 and the rate of reverse reaction is k2. Then it follows that at equilibrium k1 = k2.

Answer:

the water cycle shows the continuous movement of water within the Earth and atmosphere. it is a complex system that includes many different processes. Beckley water evaporates into water vapor, condenses to form clouds, and precipitates back to Earth in the form of rain and snow. Water in different phases moved across the atmosphere. The Cove water flows across the land, into the ground, threw the ground. Groundwater moves into plants and evaporates from plants into the atmosphere. Solid ice and snow can turn directly into gas. It can also take place when water vapor becomes solid

Explanation:

hope this helps :]

Water can take different paths while moving through water   cycle because of it's unique property to exist in different phases.

Water cycle is one of the biogeochemical cycles which describes the movement of water above and below the surface of earth. Mass of water remains constant but it's mass in different forms varies as it exists in form of  glaciers, water and water vapor.

Water gets converted from one form to another by processes such as evaporation,transpiration, condensation,precipitation and surface run off.During this , water changes it's phases from liquid to vapor and solid . Ocean plays a major role in water cycle as it is a source of 86% global evaporation of water.

It involves change in energy leading to changes in temperature. When it evaporates,it takes energy from surroundings and while condensing, it releases energy in to the environment. The evaporation phase purifies the water and then replenishes land with freshwater.

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Go to the Data tab > Sort & Filter group, and click Clear.

Go to the Home tab > Editing group, and click Sort & Filter > Clear.

Answer:

2.500 × 10⁵ cal

Explanation:

1kcal= 1000 cal

From the analysis, the number of calories in each serving of a food with 250 Calories would be 250,000 calories.

According to the illustration:

               1 Calories = 1 kilocalories

The food package reports 250 Calories

Hence, 250 Calories = 1 x 250 kilocalories

                                      = 250 kilocalories

According to metrics, 1 kilocalories = 1,000 calories

Thus, 250 kilocalories = 250 x 1000 calories

                                      = 250,000 calories

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Answer:

Gas (B)

Explanation:

Answer:

The difference is 2 pH units.

Explanation:

Let's give an arbitrary value to the H⁺ concentration of solution A, [H⁺]ₐ:

If that's the case then the pH of solution A would be:

----

The H⁺ concentration of solution B ( [H⁺]ₓ ) is 100 higher than that, so:

And its pH:

So the difference in pH values is:

Answer:

option C is correct

Explanation:

Considering the ideal gas law and the definition of Avogadro's Number, the correct option is option a. The temperature of a sample of CH₄ gas (10.34 g) in a 50.0 L vessel at 1.33 atm is 984 °C.

In first place, you have to know that ideal gases are a simplification of real gases that is done to study them more easily.

It is considered to be formed by point particles, do not interact with each other and move randomly. It is also considered that the molecules of an ideal gas, in themselves, do not occupy any volume.

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T).

The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:

P×V = n×R×T

In this case, being the molar mass of CH₄ being 16 [tex]\frac{g}{mole}[/tex], that is, the mass present in one mole of an element or compound, the number of moles that 10.34 grams contains is calculated as:

[tex]10.34 g*\frac{1 mole}{16.04 g} = 0.645 moles[/tex]

So, you know:

Replacing:

1.33 atm × 50 L= 0.645 moles× 0.082 (atm×L)/ (mol×K) ×T

Solving:

T= [1.33 atm × 50 L] ÷ [0.645 moles× 0.082 (atm×L)/ (mol×K) ]

T≅ 1257 K

Being 273 K equivalent to 0 C, then:

T= 1257 K= 984 C

In summary, the correct option is option a. The temperature of a sample of CH₄ gas (10.34 g) in a 50.0 L vessel at 1.33 atm is 984 °C.

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Answer:

I agree

Explanation:

because the sunlight passes through the atmosphere and is absorbed by earth's surface.

The green house gases in the atmosphere can change the behavior of energy on earth. Thus i agree with this statement.

The green house effect is defined as a process by which the radiations from the sun are absorbed by the green house gases like methane, Chloro fluoro carbons and not reflected back into the space. This makes the surface as insulator and prevents it from freezing.

Due to the increased level of green house gases, the temperature of the earth increases considerably and thereby causes global warming, depletion of ozone layer, smog and air pollution, etc.

It is the natural green house effect which affect the behaviour of heat energy radiated by the sun. The green house gases never let the radiations escape from the earth and increase the surface temperature of earth. This leads to global warming.

Thus green house gases affects the solar energy.

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Answer:

0.52g of Al(OH)₃

Explanation:

The reaction of aluminium nitrate, Al(NO₃)₃, reacts with KOH, as follows:

Al(NO₃)₃ + 3KOH → Al(OH)₃ + 3 KNO₃

That means 1 mole of aluminium nitrate reacts with 3 moles of potassium hydroxide.

To find moles of aluminium hydroxide we need to determine the limiting reactant finding moles of each reactant:

Moles aluminium nitrate:

0.050L * (0.20mol / L) = 0.01 moles Al(NO₃)₃

Moles KOH:

0.200L * (0.100mol / L) = 0.02 moles of KOH

Thus, for a complete reaction of 0.02 moles of KOH are needed (Using the chemical equation)

0.02 moles of KOH * (1 mol Al(NO₃)₃ / 3 mol KOH) = 0.0067 moles of Al(NO₃)₃.

As there are 0.01 moles of Al(NO₃)₃, this is the excess reactant and KOH is the limiting reactant.

The 0.02 moles of KOH produce:

0.02 moles of KOH * (1 mol Al(OH)₃ / 3 mol KOH) = 0.0067 moles of Al(OH)₃

In mass (Using molar mass of Al(OH)₃: 78g/mol):

0.0067 moles of Al(OH)₃ * (78g/mol) =

Answer:

In this section, please include the if/then statements you developed during your lab activity for each location on the map. These statements reflect your predicted outcomes for the experiment.

Location One: Select two events that you predict will be observed. If I explore two continental plates at a convergent boundary, then I will observe:

earthquakes

faults

ocean formation

mountains

volcanoes

island chains

seafloor spreading

Location Two: Select three events that you predict will be observed. If I explore two continental plates at a divergent boundary, then I will observe:

earthquakes

faults

ocean formation

mountains

volcanoes

island chains

seafloor spreading

Location Three: Select three events that you predict will be observed. If I explore two continental plates at a transform boundary, then I will observe:

earthquakes

faults

ocean formation

mountains

volcanoes

island chains

seafloor spreading

This is all I have for now! Hope this can help! :)

Answer:

6,500 gm of steam require= 3,510 kilo calories (approx)

Explanation:

Every 1 gram of water at 100° C  absorb 540 calories

So,

Total water = 6.5 kg = 6,500 gram

So,

6,500 gm of steam require = 6,500 x 540

6,500 gm of steam require= 3,510 kilo calories (approx)

According to the question,

Total water,

Temperature,

Now,

Required steam will be:

= [tex]6500\times 540[/tex]

= [tex]3510 \ kilo \ calories[/tex]

Thus the above answer is right.

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Answer:

18.998403

is the mass

The chemical reaction has been the low energy reaction containing electrons rearrangement, while nuclear reactions have been the higher energy reactions with change in nuclei.

The term nuclear reactions is defined as when there has been the including the change in the nuclei of the atom. However, the reaction has been known as the chemical reaction when the change has been processed in the electrons with the rearrangement.

The nuclear reactions have made up of a more amount of energy to be liberated, while the amount of energy included in the chemical reaction has been smaller.

Thus, the chemical reaction has been the low energy reaction including electrons rearrangement, while nuclear reactions have been the high energy reactions with change in nuclei.

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Answer:

c. 0.200 M HCI(aq)

Explanation:

The titration of a base as NH3 with hydrochloric acid is:

NH3 + HCl → NH4Cl

Where 1 mole of NH3 reacts per mole of HCl

The recommended volume to read in a burette is between 60 and 80% of its capacity.

That is 60% 50.0mL = 30mL and 80% 50.0mL = 40mL must be spent.

A 6.00M HCl spend:

20mL * (0.3mol/L) * (1L/ 6.00M) = 1mL. This solution is not the ideal for the titration.

A 0.3M HCl spend:

20mL * (0.3mol/L) * (1L/ 0.3M) = 20mL. This solution is not the ideal for the titration.

A 0.200M HCl spend:

20mL * (0.3mol/L) * (1L/ 0.200M) = 30mL. This solution ideal for the titration.

A 0.100M HCl spend:

20mL * (0.3mol/L) * (1L/ 0.100M) = 60mL. This solution is not the ideal for the titration.

Right option is:

Answer: for me everything ig

Explanation: