How many of sodium (Na) are needed to make 4.5 liters of a 1.5mol/L of Na solution?​

Answer:

heat the solution

Explanation:

i think

Answer:

The way to make a supersaturated solution is to add heat, but just a little heat won't do the job. You have to heat the water close to the boiling point. When the water gets this hot, the water molecules have more freedom to move around, and there is more space for solute molecules between them.

Answer:Nothing

Explanation:

The answer is nothing the tempatature isnt matched with the degrees this is false

Answer: The following information should be included;

What is the difference between the greenhouse effect, climate change and global warming?

What proof do we have that climate change is happening?

Why is it happening?

This problem is describe the mole-ratio composition of an allow composed by tin, lead and cadmium. Ratios are given as Sn:Pb 2.73:1.00 and Pb:Cd is 1.78:1.00, and we are asked to calculate the mass percent compositon of Pb in the allow.

In this case, according to the given information, it turns out possible realize that the following number of moles are present in the alloy, according to the aforementioned ratios:

[tex]2.73mol Sn\\\\1.00molPb\\\\\frac{1.00molPb*1.00molCd}{1.78molPb}= 0.562molCd[/tex]

Next, we calculate the masses by using each metal's atomic mass:

[tex]m_{Sn}=2.73mol*\frac{118.7g}{1mol}=324.05g\\\\ m_{Pb}=1.00mol*\frac{207.2g}{1mol}=207.2g\\\\m_{Cd}=0.562mol*\frac{112.4g}{1mol}=63.2g[/tex]

Thus, the mass percent composition of each metal is shown below:

[tex]\%Sn=\frac{324.05g}{324.05g+207.2g+63.2g} *100\%=54.5\%\\\\\%Pb=\frac{207.2g}{324.05g+207.2g+63.2g} *100\%=34.9\%\\\\\%Cd=\frac{63.2}{324.05g+207.2g+63.2g} *100\%=10.6\%[/tex]

So that of lead is 34.9 %.

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Explanation:

the investigation lasts for 7 days.

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The mole fraction of N₂ after the mixture of 4.0 L of N₂ at 15 atm with 4.0 L of H₂ at 7.0 atm is 0.68.

We can calculate the mole fraction of N₂ with the following equation:

[tex] X_{N_{2}} = \frac{n_{N_{2}}}{n_{t}} = \frac{n_{N_{2}}}{n_{N_{2}} + n_{H_{2}}} [/tex]   (1)

The number of moles of N₂ and H₂ can be found with the ideal gas law:

[tex] PV = nRT [/tex]

Where:

P: is the pressure

R: is the gas constant

T: is the temperature

V: is the volume

For nitrogen gas we have:

[tex] n_{N_{2}} = \frac{P_{N_{2}}V_{N_{2}}}{RT} [/tex]   (2)

And for hydrogen:

[tex] n_{H_{2}} = \frac{P_{H_{2}}V_{H_{2}}}{RT} [/tex]   (3)

After entering equations (2) and (3) into (1), we get:

[tex] X_{N_{2}} = \frac{\frac{P_{N_{2}}V_{N_{2}}}{RT}}{\frac{P_{N_{2}}V_{N_{2}}}{RT} + \frac{P_{H_{2}}V_{H_{2}}}{RT}} [/tex]  

Since RT are constants, we have:

[tex] X_{N_{2}} = \frac{P_{N_{2}}V_{N_{2}}}{P_{N_{2}}V_{N_{2}} + P_{H_{2}}V_{H_{2}}} [/tex]                

We know that:

[tex] P_{N_{2}} = 15 atm[/tex]                

[tex] V_{N_{2}} = 4.0 L[/tex]                

[tex] P_{H_{2}} = 7.0 atm[/tex]                

[tex] V_{H_{2}} = 4.0 L[/tex]          

so:

[tex] X_{N_{2}} = \frac{15 atm*4.0 L}{15 atm*4.0 L + 7.0 amt*4.0 L} = 0.68 [/tex]                

Therefore, the mole fraction of N₂ is 0.68.

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-Sound waves transfer energy by the motion of particles.

Explanation:

These particle-to-particle, mechanical vibrations of sound conductance qualify sound waves as mechanical waves. Sound energy, or energy associated with the vibrations created by a vibrating source, requires a medium to travel, which makes sound energy a mechanical wave.

Sound waves transfer energy by the motion of particles considered a type of mechanical energy.

Potential energy plus kinetic energy are combined to form mechanical energy. According to the concept of mechanical energy conservation, mechanical energy remains constant in an isolated system that is solely exposed to conservative forces.

The quantity of energy that a force transfers is known as mechanical work. It is a scalar quantity with joules as its SI unit, much as energy.

Since there are only microscopic forces generated by atomic collisions and no macroscopically quantifiable force, heat conduction is not regarded as a kind of work.

Transverse, longitudinal, and surface waves are the three different forms of mechanical waves. When the wave's energy goes through them, they behave differently in terms of how the medium's particles move.

Thus, option C is correct.

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In this case, according to the given information about the oxidation numbers and the compounds given, it turns out possible to figure out the oxidation number of manganese in both MnI2, manganese (II) iodide and MnO2, manganese (IV) oxide, by using the concept of charge balance.

Thus, we can define the oxidation state of iodine and oxygen as -1 and -2, respectively, since the former needs one electron to complete the octet and the latter, two of them.

Next, we can write the following [tex]x[/tex], since manganese has five oxidation states, and it is necessary to calculate the appropriate ones:

[tex]Mn^xI_2^-\\\\Mn ^xO_2^{-2}[/tex]

Next, we multiply each anion's oxidation number by the subscript, to obtain the following:

[tex]Mn^xI_2^-\rightarrow x-2=0;x=+2\\\\Mn ^xO_2^{-2}\rightarrow x-4=0;x=+4[/tex]

Thus, the correct choice is Manganese has an oxidation number of +2 in Mnl2 and +4 in MnO2.

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Answer:

D . GOD BLESS .

Explanation:

Answer:  251 K

Explanation: hope this helps :)

Mercury (I) phosphate with the chemical formula  (Hg2)3(PO4)2 has 16 atoms.

Sum of all the atoms = 6+2+8

                                   = 16 atoms

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Answer:

A mixture of chlorine gas (Cl2) and fluorine gas (F2):

✔ London dispersion forces

Explanation:

Answer:

The key to understanding why ionic and covalent compounds have different properties from each other is understanding what's going on with the electrons in a compound. Ionic bonds form when atoms have different electronegativity values from each other. When the electronegativity values are comparable, covalent bonds form.

But, what does this mean? Electronegativity is a measure of how easily an atom attracts bonding electrons. If two atoms attract electrons more or less equally, they share the electrons. Sharing electrons results in less polarity or inequality of charge distribution. In contrast, if one atom attracts bonding electrons more strongly than the other, the bond is polar.

Ionic compounds dissolve in polar solvents (like water), stack neatly on each other to form crystals, and require a lot of energy for their chemical bonds to break. Covalent compounds can be either polar or nonpolar, but they contain weaker bonds than ionic compounds because they are sharing electrons. So, their melting and boiling points are lower and they are softer.

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Answer:

Ba(OH)2 + 2 HCl → BaCl2 + 2 H2O

The reactants are present in equimolar amounts, so there is no excess or limiting reactants.

(0.0500 L) x (0.600 mol/L HCl) x (2 mol H2O / 2 mol HCl) = 0.0300 mol H2O

(4.184 J/g·°C) x (50.0 g + 50.0 g) x (25.82 - 21.73)°C = 1711.256 J

(1711.256 J) / (0.0300 mol H2O) = 57042 J/mol = 57.0 kJ/mol H2O

Explanation:

Explanation:

filling air inside an empty o2 medal containers, if air is added, the air inside, creates volume inside.

due to heat, weather,... depending on what indoor or outdoor storage said containers r placed in,;

So, I can't give you an answer, due to lack of details..sorry...

Using Hess's law we found:

1) By adding reaction 10.2 with the reverse of reaction 10.1 we get reaction 10.3:

KOH(aq) + HCl(aq)  → H₂O(l) + KCl(aq)   ΔH  (10.3)

2) The ΔHsoln must be subtracted from ΔHneut to get the total change in enthalpy (ΔH).    

The reactions of dissolution (10.1) and neutralization (10.2) are:

KOH(s) → KOH(aq)   ΔHsoln    (10.1)

KOH(s) + HCl(aq) → H₂O(l) + KCl(aq)     ΔHneut     (10.2)

1) According to Hess's law, the total change in enthalpy of a reaction resulting from differents changes in various reactions can be calculated as the sum of all the enthalpies of all those reactions.      

Hence, to get reaction 10.3:

KOH(aq) + HCl(aq) → H₂O(l) + KCl(aq)    (10.3)

We need to add reaction 10.2 to the reverse of reaction 10.1

KOH(s) + HCl(aq) + KOH(aq) → H₂O(l) + KCl(aq) + KOH(s)

Canceling the KOH(s) from both sides, we get reaction 10.3:

KOH(aq) + HCl(aq)  → H₂O(l) + KCl(aq)    (10.3)

2) The change in enthalpy for reaction 10.3 can be calculated as the sum of the enthalpies ΔHsoln and ΔHneut:

[tex] \Delta H = \Delta H_{soln} + \Delta H_{neut} [/tex]

The enthalpy of reaction 10.1 (ΔHsoln) changed its sign when we reversed reaction 10.1, so:

[tex] \Delta H = \Delta H_{neut} - \Delta H_{soln} [/tex]

Therefore, the ΔHsoln must be subtracted from ΔHneut to get the total change in enthalpy ΔH.

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Answer:

1. An independent variable is manipulated, or changed. The dependent, or responding variable, changes based on the independent variable. The dependent variable is examined.

2. It is a controlled experiment.

Explanation:

In a controlled experiment all variables are kept the same, except for the one being tested, which is called the experimental variable , or independent variable . This group is the experimental group . The group that is not affected by the experimental variable is the control group .

Very often a graph will be used to analyze the results of the experiment. The independent/experimental variable is placed on the x-axis and the dependent variable is placed on the y-axis. The dependent variable is what is measured as a result of the application of the experimental variable.

A variable that is independent is altered. Based on the independent variable, the responding variable, or dependent variable, alters. Examining the dependent variable. The experiment is carefully controlled.

In mathematical modeling, statistical modeling, and experimental sciences, there are dependent and independent variables. Dependent variables get their name because, during an experiment, their values are investigated under the presumption or requirement that they are dependent on the values of other variables due to some law or rule.

A variable that is independent is precisely what it sounds like. It is a stand-alone variable that is unaffected by the other variables you are attempting to assess. Age, for instance, could be an independent variable.

When doing an experiment, the independent variable is what you alter, and the dependent variable is what changes as a result of that change. This is an easy way to conceive of independent and dependent variables.

Thus, based on the independent variable, the responding variable, or dependent variable, alters.

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Yes according to reliable sources.

As the solar nebula cooled METAL compounds are the first to condense from a gas to a solid. The solar nebula gave birth to the Solar system.

A solar nebula is a disc-shaped cloud of gases and grain dust, which gave birth to the Sun and planets of the Solar system, approximately 4.6 billion years ago.

The solar nebula is at the beginning a mixture of interstellar gases (hydrogen and helium) and dust grains.

As the solar nebula cools, heavy elements such as metals in the disk condensate into planetesimals.

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Answer:

The volume of sulphuric acid, H₂SO₄ needed for the complete reaction with 72.2 g of sodium hydroxide, NaOH is 5.31 L

We'll begin by calculating the number of mole in 72.2 g of NaOH. This can be obtained as follow:

Mass of NaOH = 72.2 g

Molar mass of NaOH = 23 + 16 + 1 = 40 g/mol

Mole = mass / molar mass

Mole of NaOH = 72.2 / 40

2NaOH + H₂SO₄ —> Na₂SO₄ + 2H₂O

From the balanced equation above,

2 moles of NaOH reacted with 1 mole of H₂SO₄.

Therefore,

1.805 mole of NaOH will react with = 1.805 / 2 = 0.9025 mole of H₂SO₄.

Mole of H₂SO₄ = 0.9025 mole

Molarity of H₂SO₄ = 0.170 M

Volume = mole / Molarity

Volume of H₂SO₄ = 0.9025 / 0.170

Thus, the volume of H₂SO₄ needed for the reaction is 5.31 L

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Taking into account the definition of pH and pOH, the [H⁺] is 3.16×10⁻⁵ M and the solution will be acid.

First of all, pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.

The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions, that is, the concentration of hydrogen ions or H₃O⁺:

pH= - log [H⁺]= - log [H₃O⁺]

Similarly, pOH is a measure of hydroxyl ions in a solution and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:

pOH= - log [OH⁻]

The following relationship can be established between pH and pOH:

pH + pOH= 14

In this case, being pOH= 9.50, pH is calculated as:

pH + 9.40= 14

pH= 14 - 9.50

pH= 4.50

Replacing in the definition of pH the concentration of H⁺ ions is obtained:

- log [H⁺]= 4.50

Solving :

[H⁺]= 10⁻⁴ ⁵

[H⁺]= 3.16×10⁻⁵ M

The numerical scale that measures the pH of the substances includes the numbers from 0 to 14, being acidic solutions with a pH lower than 7, and basic those with a pH greater than 7. The pH = 7 indicates the neutrality of the solution.

In this case, the pH has a value of 4.50. So, the solution is acidic.

In summary, the [H⁺] is 3.16×10⁻⁵ M and the solution will be acid.  

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The molarity of the solution is 0.01.

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This question is asking for a method for the determination of the freezing point in a solution that does not have a noticeable transition in the cooling curve, which is basically based on a linear fit method.

The first step, would be to understand that when the transition is well-defined as the one on the attached file, we can just identify the temperature by just reading the value on the graph, at the time the slope has a pronounced change. For instance, on the attached, the transition occurs after about 43 seconds and the freezing point will be about 4 °C.

However, when we cannot identify a pronounced change in the slope, it will be necessary to use a linear fit method (such as minimum squares) to figure out the equation for each segmented line having a significantly different slope and then equal them so that we can numerically solve for the intercept.

As an example, imagine two of the segmented lines have the following equations after applying the linear fit method:

[tex]y=-3.5 x + 25\\\\y=-0.52 x + 2[/tex]

First of all, we equal them to find the x-value, in this case the time at which the freezing point takes place:

[tex]-3.5 x + 25=-0.52 x + 2\\\\-3.5 x+0.52 x =2-25\\\\x=\frac{-23}{-2.98}=7.72[/tex]

Next, we plug it in in any of the trendlines to obtain the freezing point as the y-value:

[tex]y=-3.5 (7.72) + 25\\\\y = 1.84[/tex]

This means the freezing point takes place after 7.72 second of cooling and is about 1.84 °C. Now you can replicate it for any not well-defined cooling curve.

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Answer:The plates are not fixed but are constantly moving atop a layer of solid and molten rock called the mantle. The Ring of Fire is a string of volcanoes and sites of seismic activity, or earthquakes, around the edges of the Pacific Ocean. ... A hotspot is a place in the middle of a tectonic plate where hot magma rises.

Explanation: