A stock solution containing Mn2 ions was prepared by dissolving 1.269 g pure manganese metal in nitric acid and diluting to a final volume of 2.000 L. The following solutions were then prepared by dilution: For solution A, 40.00 mL of stock solution was diluted to 1500.0 mL. For solution B, 10.00 mL of solution A was diluted to 250.0 mL. For solution C, 20.00 mL of solution B was diluted to 550.0 mL. a Calculate the concentration of the stock solution.

Answer:

16.7%

Explanation:

40 ml of salt water + 200 ml of solution = 240 ml

40/240 = 4/24 = 1/6=16.7%

The answer would be 4.

The agencies are:

Department of Agriculture's Forest Service (AFS)

Department of the Interior's Bureau of Land Management (BLM)

Fish and Wildlife Service (FWS)

National Park Service (NPS)

These four agencies cover around 95% of the land and are the only federal agencies.

I learned about these agencies in school.

According to the equation given, we have N2 + 3H2 → 2NH3.

Therefore, to determine the moles of NH3 we have to do the following-

1.3 mol H2 × 2 mol NH3 / 3 mol H2 = 0.87 mol

Answer: .87 moles of NH3 are produced from 1.3 moles of H2.

I hope this helps!

Answer:

read the story

Explanation:

read it and then you will find the answer

Answer:

Ptotal=P1+P2+… +Pn. + P nExplanation:

its c

The amount of the sample remaining at 4pm is 0.0625 g

We'll begin by calculating the number of half-lives that has elapsed

Half-life (t½) = 1 hour

Time (t) = 4 hour

n = t / t½

n = 4 / 1

Number of half-lives (n) = 4

Initial amount (N₀) = 1 g

[tex]N = \frac{N_0}{ {2}^{n}} \\ \\ N = \frac{1}{ {2}^{4}} \\ \\ N = \frac{1}{16} \\ \\ N = 0.0625 \: g[/tex]

Thus, the amount remaining at 4pm is 0.0625 g

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Answer:

chlorine

Explanation:

Answer:chlorine reacts with hydrogen peroxide

Explanation:

Answer:

EDTA disodium salt | C10H14N2Na2O8

Explanation:

[tex]pH = -\log[H^{+}] \\\\\implies \log[H^{+}] = -pH\\\\\implies [H^{+}] = 10^{-pH}\\\\\implies [H^{+}] = 10^{-4.83} = 0.000015[/tex]

Answer:

i can't understand the question

Answer:

a.2.55e-7

b.6830

Explanation:

AnswerExplanation:I finsished d

Answer:

17.55L

Explanation:

0.48mol : 11.7

0.72mol :   x

0.48x = 8.424

x = 17.55

Answer:

oxygen (O2 )

Explanation:

The freezing point of the solution is - 0.12 oC.

We know that;

ΔT = K m i

ΔT = Freezing point depression

K = Freezing constant

m = molality

i = Van't Hoff factor

Number of moles of sucrose= 2.23g/342 g/mol = 0.0065 moles

Mass of solvent in Kg = 0.1 Kg

Molality of the solution = 0.0065 moles/ 0.1 Kg = 0.065 m

Now;

ΔT = 1.86 oC/m × 0.065 m × 1

ΔT = 0.12 oC

Freezing point of pure water = 0 oC

Freezing point of solution =  0 oC -  0.12 oC = - 0.12 oC

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Answer:

1.1 million pounds

Explanation:

Answer:

1.1 million pounds

Explanation:

that's a lot of water above us!!

The final temperature of the mixture in the coffee cup calorimeter is; 19.467 °C

According to the law of energy conservation:

As such; the heat transfer in the liquid water is equal to heat gained by the ice

Heat transfer by liquid water is therefore;

However, since 18g of water makes one mole

T2 = 19.467°C

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Answer:

the lowest point of the wave is called Trough

Answer:

Trough is the correct answer

Explanation:

The highest part of the wave is called the crest. The lowest part is called the trough.

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The Correct choice is ~ D

Solute is the substance that dissolves into another substance

Answer:

the small intestine where nutrients are absorbed.

To balance a chemical equation you must pay attention that the algebraic equation has the same number of element atoms in reactant and the product.

A chemical equation is a term to refer to the symbolic description of a chemical reaction, that is, the written representation of symbols. For example:

The balance of an equation can be related to the law of conservation of matter, that is, the number of atoms of each element in the reactants is in the result.

Note: This question is incomplete, because the information some information is missing.

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The explanation to the question is stated as follows:

Newton's first law of motion states that: a body will continue in its state of rest or uniform motion unless an external force acts on it. So then, the ball initially possesses potential energy because it was at rest. While the leg of the soccer player possesses kinetic energy because its in motion.

Thus, when the player hits the ball, a force known as push has been applied. This would ensure that the ball compels and moves in the direction of the applied force. Therefore after the interaction, the leg of the player now possesses potential energy, since it would come to rest after hitting the ball. While the ball would start moving, now possessing kinetic energy.

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This problem, is describing two scenarios, the first one, a reaction between potassium carbonate and nitric acid, and also this very same acid with sodium carbonate. In addition, it is asked to set up two equations whereby you can get the grams of nitric acid needed to react with the unknown grams of both carbonates.

In this case, we can start off by designating the unknown mass of potassium carbonate as X and that of sodium carbonate as Y, so that we will be able to provide a reliable answer. Next, we write the corresponding chemical equations that take place:

K2CO3 + 2HNO3 --> 2KNO3 + H2O + CO2

Na2CO3 + 2HNO3 --> 2NaNO3 + H2O + CO2

After that, we can set up the conversion by considering the following calcultion track:

g Carbonate --> mol Carbonate --> mol HNO3 --> g HNO3

The conversion from grams to moles involve the carbonates' molar mass and the conversion from moles of nitric acid to grams, its molar mass well. In addition, we need the 1:2 mole ratio of the carbonates to nitric acid that it is evidenced in the reaction.

Therefore, the resulting equations that can be set up are shown as follows:

[tex]X g K_2CO_3 *\frac{1mol K_2CO_3 }{138.2 gK_2CO_3 } \frac{2molHNO_3}{1molK_2CO_3 } *\frac{63.1gHNO_3}{1molHNO_3} \\\\Y g Na_2CO_3 *\frac{1mol K_2CO_3 }{105.99 gK_2CO_3 } \frac{2molHNO_3}{1molNa_2CO_3 } *\frac{63.1gHNO_3}{1molHNO_3}[/tex]

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Answer:

c) single bonds, double bonds, carbon atoms and hydrogen atoms

Explanation:

A=Sun

B=Earth

C=Neptune.

hope my answer will definitely help you out.

Answer:

The process by which food is broken down to release energy is called respiration

I hope it helps.

Answer:

Respiration

Explanation:

hope this helps.

Entropy increases in reaction 1 due to increase in the number of particles while entropy decreases in reaction 2 due to decrease in the number of particles.

Entropy refers to the degree of disorderliness in a system. The higher the entropy, the more disorderly the system is and the lower the entropy, the less disorderly the system is. We must note that entropy increases with increase in the number of particles.

In the reaction,  2 KClO3 (s)⇌2 KCl (s)+3 O2 (g), entropy increases because one of the products is a gas and the number of particles increases from left to right. In the second reaction, CoCl2 (s)+6 H2O (g)⇌CoCl2⋅6H2O, entropy decreases because the number of particles decreases.

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Considering the definition of percentage by mass and molality, the molality of Na₃PO₄ in the solution is 0.948 [tex]\frac{moles}{kg}[/tex].

The percentage by mass expresses the concentration and indicates the amount of mass of solute present in 100 grams of solution.

In other words, the percentage by mass of a component of the solution is defined as the ratio of the mass of the solute to the mass of the solution, expressed as a percentage.

The percentage by mass is calculated as the mass of the solute divided by the mass of the solution, the result of which is multiplied by 100 to give a percentage. This is:

[tex]percentage by mass=\frac{mass of solute}{mass of solution}x100[/tex]

Molality is the ratio of the number of moles of any dissolved solute to kilograms of solvent.

The Molality of a solution is determined by the expression:

[tex]molality=\frac{number of moles of solute}{kilograms of solvent}[/tex]

Considering 100 grams as a sample of the solution, then the value of the percentage of concentration given indicates that  13.5 g correspond to Na₃PO₄.

Remember that percent concentration by mass is calculated using the mass of solute and the mass of the solution, which includes both the solute and the solvent. Then:

mass solution= mass solute + mass solvent

100 g= 13.5 g + mass solvent

100 g - 13.5 g= mass solvent

86.5 g= mass solvent

Then, you know:

Then, replacing in the definition of molality:

[tex]molality=\frac{0.082 moles}{0.0865 kg}[/tex]

Solving:

molality= 0.948 [tex]\frac{moles}{kg}[/tex]

Finally, the molality of Na₃PO₄ in the solution is 0.948 [tex]\frac{moles}{kg}[/tex].

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If the absorbance of a solution of curcumin which is too concentrated is measured, the absorbance will be unusually high.

Spectrometry measures the interaction of light with molecules. The absorbance refers to how much light that interacts with molecules of the substance. The more the concentration of the substance the higher the absorbance of the solution.

Hence, if  the absorbance of a solution of curcumin which is too concentrated is measured, the absorbance will be unusually high. An unusually high absorbance tells us that the solution is too concentrated.

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This question is describing the following chemical reaction at equilibrium:

[tex]A\rightleftharpoons B[/tex]

And provides the relative amounts of both A and B at 25 °C and 75 °C, this means the equilibrium expressions and equilibrium constants can be written as:

[tex]K_1=\frac{90\%}{10\%}=9\\\\K_2=\frac{20\%}{80\%} =0.25[/tex]

Thus, by recalling the Van't Hoff's equation, we can write:

[tex]ln(K_2/K_1)=-\frac{\Delta H}{R}(\frac{1}{T_2} -\frac{1}{T_1} )[/tex]

Hence, we solve for the enthalpy change as follows:

[tex]\Delta H=\frac{-R*ln(K_2/K_1)}{(\frac{1}{T_2} -\frac{1}{T_1} ) }[/tex]

Finally, we plug in the numbers to obtain:

[tex]\Delta H=\frac{-8.314\frac{J}{mol*K} *ln(0.25/9)}{[\frac{1}{(75+273.15)K} -\frac{1}{(25+273.15)K} ] } \\\\\\\Delta H=4,785.1\frac{J}{mol}[/tex]

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