A chemist makes up a solution by dissolving 39.0 g of Mg(NO3)2 in enough water to produce a final solution volume of 257 mL. To calculate the molarity of the solution, what additional information is needed

Answer:Melting

Explanation:

It was right when i took the test

A rock must be heated to between 600 and 1,300 degrees Celsius (1,100 and 2,400 degrees Fahrenheit) in order to melt and become molten rock. At point K the event occurring is melting.

The lithosphere of the Earth, also referred to as the crust, is a solid layer of the globe where rocks melt. Between 50 and 200 kilometers beneath the surface, rocks dissolve on average.

The rock will melt under excessive heat or pressure and turn into lava. Instead of metamorphic rock, an igneous rock will emerge as a result of this. An igneous rock called granite is created when magma cools slowly underneath.

Thus the correct option is C.

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Answer:

2+

Explanation:

I just did this question.

Answer:

The atom is Na, sodium with a net charge of +1 because it lost an electron. it usually has 11 electrons.

Explanation:

sodium has a 11 protons  with an atomic mass of 23-11=12 neutrons.

To see the number of atoms of an element in a given molecule we need to multiply stoichiometry to the number that is written on the foot of the element that is stoichiometry. Therefore, the charge on atom is +1.

Atom is the smallest particle of any element, molecule or compound. Atom can not be further divided. Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit.

In the nucleus, proton and neutron are present. Electron has -1 charge while proton has +1 charge. Neutron is neutral that is it has no charge. So overall the charge of nucleus is due to only proton, not by neutron.

Since the number of electrons is 10. The number of protons is 11. So, there is loss of one electron, so the charge on atom is +1.

Therefore, the charge on atom is +1.

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Answer:

a>8

Explanation:

Hoped that helped!

Answer:

[tex]a > 8[/tex]

Explanation:

If we take a look at this problem, we can see that we need to solve for a.

[tex]a - 3 > 5[/tex]

Just like solving a normal equation, we can take add 3 on both sides like so:

[tex]a - 3 > 5\\ +3 +3\\----\\a > 8[/tex]

As our final answer, we get [tex]a[/tex] is greater than 8!

Hoped this helped!

-Bob Ross

Answer:

9-fluorenone binds more strongly to the stationary phase.

Explanation:

9-fluorenone is more polar than fluorene  because it possesses a carbonyl group. Recall that the stationary phase is alumina and alumina is a polar adsorbent. Alumina is a top choice for the separation of components that contain a weakly or moderately polar component.  These polar components  of the mixture are retained for a longer time and more selectively by the adsorbent.

The fluorene is eluted first with the Petroleum ether, this makes it easier to elute the 9-fluorenone with the dichloromethane. The 9-fluorenone will be slower because it is more strongly attracted to the alumina owing to its polar carbonyl group.

Fluorene moves faster because its' polarity is the same as Petroleum ether and also opposite of the alumina. If the order of solvents is reversed and dichloromethane is first used, the 9-fluorenone binds more strongly to the alumnina making it difficult to elute fluorene using Petroleum ether.

Answer: I believe it’s D

Explanation:

Answer:

But it is likley that sunsets and sunrises would be a lot slower due to Venus having a slow spin rate and the Sun being brighter due to Venus being closer to the Sun than Earth. Brightness: As noted above Venusian sunsets and sunrises would be a lot brighter and a lot more brilliant than on Earth due to Venus being closer to the Sun.

Explanation:

Answer:

umm im just here for the points, im sorry if i knew i would answer it i dont take chemistry

Explanation:

Answer:

c.

The high salinity of the surface runoff is harmful to freshwater ecosystems.

Explanation: cause that's the answer

The negative impact of deicing roads with salt on the environment is the high salinity of the surface runoff is harmful to freshwater ecosystems. Therefore, option (C) is correct.

Deicing can be described as the process of removing snow, ice, or frost from a surface. The application of chemicals that not only deice but also remain on a surface to delay the reformation of ice for a certain period of time.

Deicing is accomplished by mechanical methods through the application of heat, various salts or brines, alcohols, glycols, or by a combination of these different techniques.

Deicing of roads has been done with salt, often mixed with sand and gravel, on slick roads. Sodium chloride is generally used, as it is inexpensive and can be available in large quantities.

Since salt water still freezes at −18 °C and also has a tendency to cause corrosion, rusting the steel used in most vehicles. It can be toxic to some plants and animals depending on the concentration of salt.

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Answer:

197.48 g/mol

Explanation:

We must first discover the relative atomic mass of M;

From;

M + 2[ 16 + 1 ] = 199.416

M + 34 = 199.416

M = 199.416 - 34

M= 165.416

Since the sulphide is MS

molar mass = 165.416 + 32.065

molar mass= 197.48 g/mol

The molar mass of the corresponding sulfide is  197.48 g/mol

Since The molar mass of M(OH)2, formed by the hypothetical metal M, is 199.416 g/mol.

Now the atomic mass of M should be

M + 2[ 16 + 1 ] = 199.416

M + 34 = 199.416

M = 199.416 - 34

M= 165.416

Since the sulphide is MS

So,

molar mass = 165.416 + 32.065

molar mass= 197.48 g/mol

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Answer:

30.4g of Br2

Explanation:

2HBr --> H2 + Br2

From the stochiometry of the reaction;

2 mol of HBr reacts to form 1 mol of Br2

Mass of HBr = Molar mass * Mol = 80.91 * 2 = 161.82g

Mass of Br2 =  Molar mass * Mol = 159.8 * 1 = 159.8g

161.82g of HBr forms 159.8g of Br2

30. 8g would the form x?

161.82 = 159.8

30.8 = x

x = 30.8 * 159.8 / 161.82 = 30.4g of Br2

Answer:

.2758 g/cm

Explanation:

density = mass / volume

267/968 = .2758

Answer:

0.7692 M

Explanation:

[tex]m[/tex] = Mass of sample = [tex]20\ \text{g}[/tex]

[tex]V[/tex] = Volume of solution = [tex]150\ \text{mL}[/tex]

[tex]V_1[/tex] = Initial volume taken out of the stock solution = [tex]15\ \text{mL}[/tex]

[tex]Mo[/tex] = Molar mass of NaOH = [tex]39.997\ \text{g/mol}[/tex]

[tex]V_2[/tex] = Final volume of solution = [tex]65\ \text{mL}[/tex]

Molarity of stock solution is given by

[tex]M_1=\dfrac{m}{MoV}\\\Rightarrow M_1=\dfrac{20}{39.997\times 0.15}[/tex]

[tex]M_1V_1=M_2V_2\\\Rightarrow M_2=\dfrac{M_1V_1}{V_2}\\\Rightarrow M_2=\dfrac{\dfrac{20}{39.997\times 0.15}\times 0.015}{0.065}\\\Rightarrow M_2=0.7692M[/tex]

The concentration of NaOH for the final solution is 0.7692 M

Answer:

The concentration of vacancies in fcc silver is [tex]6.6105\times 10^1^4 vacancies/cm^3[/tex]

Explanation:

Given is - silver (fcc lattice)

Temperature = 250°C = 523K

Activation energy for vacancy creation ,[tex]Q_v[/tex] =79.5 kJ/mol

Silver has a fcc crystal lattice structure with basis

Lattice parameter = 0.49nm = [tex]4.09\times 10^-^8[/tex]m

Now , let us calculate number of silver atoms"(lattice points)per [tex]cm^3[/tex]

 [tex]N=\frac{4atoms/cell}{4.09\times10^-^8cm^3}[/tex]

     =[tex]5.86\times10^2^2 Ag[/tex] atoms/[tex]cm^3[/tex]

Concentration of vacancies is given by the formula -

 [tex]N_v =N_e_x_p\frac{-Q_V}{R.T_}[/tex]

here,

[tex]N_v = concentration of vacancies \\[/tex]

[tex]N= number of atoms[/tex] [tex]per[/tex] [tex]cm^3[/tex]

[tex]Q_v=[/tex] Activation energy for vacancy creation

T = Temperature

R = constant =[tex]8.314 J K^-^1 mole^-^1[/tex]

Now , putting the given values in the formula -

[tex]N_v= (5.85\times10^2^2atomscm^-^3)exp(\frac{-79.5KJ/mole}{8.314\timesJK^-^1mole^-^1})[/tex]

      =[tex]6.6105\times10^1^4vacnacies/cm^3[/tex]

Hence , the answer is [tex]6.6105\times10^1^4vacnacies/cm^3[/tex]

Answer:

The answer to your question is given below.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below below:

2C8H18 + 25O2 —> 16CO2 + 18H2O

From the balanced equation above,

2 moles C8H18 reacted to produce 18 moles of H2O.

Finally, we shall determine the number of moles of H2O produced by the reaction of 1.5 moles of C8H18. This can be obtained as follow:

From the balanced equation above,

2 moles C8H18 reacted to produce 18 moles of H2O.

Therefore, 1.5 moles of C8H18 will react to produce = (1.5 × 18)/2 = 13.5 moles of H2O.

Thus, 13.5 moles of H2O were obtained from the reaction.

Answer:

I think it's B, when hair begins to grow.

Explanation:

Good luck! <3

Enzymes are potent catalysts because they lower the activation energy for the reactions they catalyze (Option D).

A catalyst is any molecule capable of lowering the activation energy of a given chemical reaction, thereby making it possible in normal conditions.

Proteins called enzymes and specific types of RNA called ribozymes are well known due to their ability to bind substrates in a chemical reaction in order to generate one or more chemical products, which always require a certain amount of energy in order to carry out such chemical reactions.

Therefore, with this data, we can see that enzymes are biological catalysts capable of lowering the activation energy and thus carry out chemical reactions in normal cellular conditions such as for example, convert sugar glucose (i.e. a carbohydrate) into two molecules of pyruvate, which is a step of cellular respiration metabolic pathway.

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Answer: 1 unit, charge of 0.

Explanation: Neutrons have a charge of 0 because they are neutral. Both protons and neutrons have a mass of 1 Amy.

Answer:

The first ionization energy varies in a predictable way across the periodic table. The ionization energy decreases from top to bottom in groups, and increases from left to right across a period. Thus, helium has the largest first ionization energy, while francium has one of the lowest.

Explanation:

Answer:

0.882M of H2O2

Explanation:

A 3% solution by mass of H2O2 is a solution 3g of H2O2 in 100g of solution.

We need to convert the grams of solution to liters and the grams of H2O2 to moles to find molarity:

Moles H2O2:

3g H2O2 * (1mol / 34.01g) = 0.0882 moles H2O2.

Liters of solution:

100g solution * (1mL / 1g) * (1L / 1000mL) = 0.100L

Molarity (Ratio of moles of solute and liters of solution is:

0.0882 moles / L = 0.882M of H2O2

Answer:

B

Explanation:

the model is to represent something in reality

In an experiment, a model can help a scientist make the experimental setup match reality as closely as possible.

An empirical technique that settles conflicting models or hypotheses is called an experiment. Additionally, experiments are used by researchers to confirm or refute new or current theories.

Because experiments are used to verify a hypothesis, an axiom, or phenomena with a theoretical foundation in order to transform it into a law or a theorem like Newton laws, they play a crucial role in the progress of science.

Science uses experiments in many different ways. One of its key functions is to test hypotheses and serve as the foundation for scientific knowledge. It may also indicate the need for a new theory by refuting an established hypothesis or by revealing a new phenomenon that requires an explanation.

Thus, option B is correct.

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Answer:

Alikes dissolve. Polar substances dissolve in polar solvents and nonpolar substances dissolve in nonpolar solvents. So how they reacted showed us whether or not they were polar or nonpolar. Such as water and vinegar. They are both polar molecules so they were polar.

Answer:

all of the above

Explanation:

Answer:

it will fail

Explanation:

Answer:

Both benzoic acid and chloroethane will be extracted into the CH2Cl2 layer. a small amount of the benzoic acid may be found in the water layer.

Explanation:

Both benzoic acid and chloroethane are more soluble in organic solvents. benzoic acid can only be soluble in water when it is converted into a benzoate.

Hence, only a small amount of the benzoic acid may be found in the water layer. Both benzoic acid and chloroethane are largely extracted into the dichloromethane layer.

Answer:

pH = 8.34

Explanation:

Formic acid reacts with a strong base producing formate ion, HCOO⁻, the equilibrium is:

Kb = [HCOOH] [OH⁻] / [HCOO⁻]

Where Kb is basic equilibrium constant = Kw / Ka = 1x10⁻¹⁴ / 1.8x10⁻⁴ = 5.56x10⁻¹¹

[HCOOH] and [OH⁻] comes both from formate ion, that means  [OH⁻] = [HCOOH] = X, our incognite

And [HCOO⁻] is molarity of the solution. We need to determine this:

Moles of formate = Moles of NaOH added until equivalence point:

29.80mL = 0.02980L * (0.1567mol / L) = 4.670x10⁻³ moles NaOH = Moles Formate

And total volume of the solution is:

29.80mL + 25mL = 54.8mL = 0.0548L. Molarity is:

4.670x10⁻³ moles / 0.0548L = 0.08522M

Replacing in Kb expression:

Kb = [HCOOH] [OH⁻] / [HCOO⁻]

5.56x10⁻¹¹ = [X] [X] / [0.08522M]

4.738x10⁻¹² = X²

X = [OH⁻] = 2.177x10⁻⁶M

pOH = -log [OH⁻] = 5.66

And pH = 14 - pOH is:

Answer:

No its a chemical Change

Explanation:

Answer: chemical change

Explanation: Copper turns green because of chemical reactions with the elements. ... Just as iron that is left unprotected in open air will corrode and form a flaky orange-red outer layer, copper that is exposed to the elements undergoes a series of chemical reactions that give the shiny metal a pale green outer layer called a patina.