help me please!


What pressure will be required for neon at 30°C to have the same density as nitrogen at 20°C and 1.0 atm?

Answer:

coal

Explanation:

If a  sample of metal has a mass of 2272 grams. Its dimensions are 5 cm by 5 cm by 8 cm, then the density of the sample of the metal would be 11.36 grams / centimeter³.

It can be defined as the mass of any object or body per unit volume of the particular object or body.

ρ = mass / volume

As given in the problem sample of metal has a mass of 2272 grams. Its dimensions are 5 cm by 5 cm by 8 cm.

The density of the metal  = 2272 / (5 × 5× 8)

                                         = 11.36 gram / cm³

Thus, the density of the metal would be 11.36 grams / cm³.

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Answer: 0.01175

Explanation:

The mass of each salt which will be added to the mixture is:

NaH₂PO₄ =  1.876 g

Na₂HPO₄ =  4.879 g

To make this buffer, phosphoric acid and/or its salts can also be combined in the following ways:

H₃PO₄ and Na₂HPO₄;

H₃PO₄ and Na₃HPO₄

The acid must be in the second ionisation if we are to have a buffer at 7.540, thus we would pick pKa2 = 7.198 for the buffer capacity.

7.540 = 7.198 + log[A⁻]/[HA]

log[A⁻]/[HA] = 0.342

[A⁻]/[HA] =

[A⁻]/[HA] = 2.198

[A⁻] = 2.198*[HA]

The concentration of the acid is conjugated to base and must be equal to the concentration of the buffer 0.0500 M, so:

[A⁻] + [HA] = 0.0500

2.198*[HA] + [HA] = 0.0500

3.198*[HA] = 0.0500

[HA] = 0.01563 M

[A⁻] = 0.0500 - 0.01563

[A⁻] = 0.03436 M

The mixed reaction is: NaH₂PO₄ + Na₂HPO₄ → HPO₄⁻² + 3Na + H₂PO₄⁻

The second ionization is:

H₂PO₄⁻ ⇄ HPO₄⁻² + H⁺

Because H₂PO₄⁻ is the acid form, its concentration is the same as NaH₂PO₄, and HPO₄⁻² is the conjugated base, and its concentration is the same as Na₂HPO₄ (stoichiometry is 1:1 for both).

If you want to prepare something for buffering, you must first have a solution of the species H2PO4 and HPO42, so that you can mix the mixture of:

H3PO4 and Na2HPO4 (the acid is tricrotic, forming H2PO4 as a result),

The dissociation of the salt Na2HPO4 into Na+ and HPO42);

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The gas is oxygen which causes the splint to relight and the reaction is of hydrogen peroxide resulting into water and oxygen.

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Answer:

Explantion

Here, we want to get the number of moles in 60 g sample of NaCl

Mathematically, to get this, we have to divide the mass given by the molar mass of NaCl

Thenmolar mass of NaCl is 58.44 g/mol

Thus, we have the number of moles as:

There are two chiral centers in the ethambutol molecule, but only three possible stereoisomers (structures attached below).

In general, the number of stereoisomers of a chiral molecule is 2ⁿ, where n is the number of chiral centers, so for ethambutol it should be 2² = 4. However, if the molecule is symmetrical (in this case it has a plane of symmetry), then there is an R,S-isomer that is not optically active as a whole because the chiral centers cancel each other out. This is a so-called meso-isomer. So, in the end, we have two enantiomers (R,R- and S,S-) and a meso-isomer, giving us three stereoisomers in total.

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Answer:

this is Daltons atomic theory

Answer:

this means that energy cannot be created or destroyed

Explanation:

it is because energy can change into many different forms such as heat or nuclear during chemical reactions

Considering the definition of calorimetry, if 200.0 g of ice absorb 1255.0 J of heat, the temperature change is 2.988°C.

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

Sensible heat is defined as the amount of heat that a body absorbs or releases without any changes in its physical state (phase change). So, the amount of heat that a body receives or transmits is determined by the following expression:

Q = c×m×ΔT

Where:

In this case:

Replacing in the definition of calorimetry:

1255 J = 2.1 J/gC× 200 g× ΔT

Solving:

1255 J ÷(2.1 J/gC× 200 g)= ΔT

2.988 °C= ΔT

Finally, the temperature change is 2.988°C.

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Answer:

it's C

Explanation:

the mitochondria makes energy for the cell so without it there's no energy for the cell

Answer:

CaCO3

Explanation:

Pure calcite has the composition CaCO3. However, the calcite in limestone often contains a few percent of magnesium. Calcite in limestone is divided into low-magnesium and high-magnesium calcite, with the dividing line placed at a composition of 4% magnesium. High-magnesium calcite retains the calcite mineral structure, which is distinct from that of dolomite, MgCa(CO3)2.[18] Calcite can also contain small quantities of iron and manganese.[19] Manganese may be responsible for the fluorescence of impure calcite, as may traces of organic compounds

The true statement about the reaction is that the reaction reaches equilibrium around 1.5 seconds.

We say that a reaction is reversible if the reaction can proceed both in the forward and the reverse directions. Let us recall that it is possible for a reversible reaction to attain a status of dynamic equilibrium. The status of dynamic equilibrium is the status where the rate of the forward reaction is equal to the rate of reverse reaction.

If we look at the graph as we have it we would notice that there is such a point of dynamic equilibrium as we survey the system around 1.5 seconds.

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The true statement about the reaction is the reaction reaches equilibrium around 1.5 seconds. Thus option D is correct.

Reversible reaction is defined as a reaction in which the transformation of both reactants and products into one another takes place simultaneously.

If a response may occur in both the forward and reverse directions, we say that it is reversible. Let's not forget that a reversible reaction can reach a state of dynamic equilibrium. The condition known as dynamic equilibrium occurs when the forward reaction rate and the backward reaction rate are equal.

If we were to examine the graph as it currently stands, we would see that the system reaches a point of dynamic equilibrium after 1.5 seconds of observation.

Thus, the true statement about the reaction is the reaction reaches equilibrium around 1.5 seconds. Thus option D is correct.

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Answer:

What is class??

Explanation:

please tell the topic

Two solutions are made by mixing sugar and enough water to make a 1 liter solution. 10% sugar has more solvent.

In chemistry, a solution is a homogeneous mixture of two or more compounds in their relative proportions that can be continually altered up to what is referred to as the limit of solubility. Although the word "solution" is frequently used to refer to the liquid state of matter, solutions of gases and solids are also possible. A solute is dissolved by a solvent (s), which is a substance (from the Latin solv, "loosen, untie, solve,") to produce a solution. The most common form of a solvent is a liquid, although other forms include solids, gases, and supercritical fluids. Depending on the temperature, a different amount of solute can dissolve in a given volume of solvent. Solvents are extensively utilized in paints, paint removers, inks, and dry cleaning.

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It is better to use the analytical balance for smaller amounts of sodium hydroxide (up to a couple of grams).

The sensitivity of the analytical balance goes to a couple of tenths of a milligram, while the sensitivity of a top-loading balance goes to tens of milligrams at best. The amount of water absorbed by sodium hydroxide is significant, but not too great relative to the mass of the sample. With this in mind, it is far more recommendable to use the analytical balance over the top-loading balance in order to be able to register the change in mass at all.

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''They carry energy''. is the right statement about waves.

A wave is defined as a disturbance in a medium that carries energy without any movement of particles. It may take elastic deformation, a variation of pressure, electric intensity, magnetic intensity, electric potential, and temperature. There are three types of waves i.e. matter waves, mechanical waves, and electromagnetic waves.

All types of waves have the same basic properties of reflection, refraction, diffraction, and interference. All waves have a wavelength, frequency, speed, and amplitude. A wave can be explained by its length, amplitude, and frequency. All waves transfer energy from one place to another, they can also be reflected as well as refracted.

So we can conclude that option A is the right answer about the waves.

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The pH of the solution after 28.0 ml of NaOH have been added to the acid exists 0.85.

The balanced reaction between base and acid exists;

NaOH + HCl → NaCl + H₂O

NaOH exists a strong base and HCl exists a strong acid therefore complete dissociation. Stoichiometry of acid to base exists 1: 1.

The number of moles of base added - 0.5 M /1000 mL/L × 28.0 mL = 0.014 mol

the number of acid moles present - 0.5 M /1000 mL/L × 50.0 mL = 0.025 mol.

acid reacts with base 1: 1 ratio

Therefore excess amount of acid present - 0.025 - 0.014 = 0.011 mol

Total volume = 50.0 + 28.0 = 78.0 mL

[H⁺] = 0.011 mol/0.078 L = 0.14 M

Therefore, pH = -log [H⁺]

substitute the values in the above equation, we get

pH = -log(0.14)

simplifying the above equation, we get

pH = 0.85.

Therefore, the pH of the solution after 28.0 ml of NaOH have been added to the acid exists 0.85.

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America can best accelerate its transition to renewable energy by :

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The percent composition are the percent in mass of each atom in the molecule.

Since we know that the molar mass of the substance is 334.0 g/mol, we can use it to figure out how much of each atom we have per molecule.

Starting from carbon, we know it is 75.42% of the mass.

In 1 mol of the substance, there are 334.0 g, 75.42% of which is from carbon atoms.

So, in 1 mol of the substance, there are the following mass of carbon:

The aromic mass of the carbon atom is 12.0107 g/mol.

That is, in 1 mol of the substance -> 251.9028 g of C.

That mass of carbon is equivalent to:

So, in 1 mol of the substance -> 251.9028 g of C -> 21 mol of C. This means that for each molecule of the substance we have 21 atoms of carbon.

Now, we can just repeat the process for Hydrogen, Nitrogen and Oxygen.

Hydrogen has an atomic mass of 1.00794 g/mol, and the percent composition of it is 6.63%, so:

So, for each molecule of the substance there are 22 atoms of hydrogen.

Nitrogen has an atomic mass of 14.0067 g/mol, and the percent composition of it is 8.38%, so:

So, for each molecule of the substance there are 2 atoms of nitrogen.

Oxygen has an atomic mass of 15.9994 g/mol, and the percent composition of it is 9.57%, so:

So, for each molecule of the substance there are 2 atoms of oxygen.

To summarize, we have, for each molecule of the substance:

- 21 carbon

- 22 hydrogen

- 2 nitrogen

- 2 oxygen

So, the molecular form of the substance is C₂₁H₂₂N₂O₂.

Answer: The discovery of protons and isotopes

Explanation:  Mendeleev's arrangement by changing the criteria by which elements were arranged and assigned atomic numbers. Mendeleev arranged the periodic table based on the atomic mass of an atom of an element and its chemical properties.

The metals that are able to displace iron sulfate from solution are magnesium and aluminum.

The electrochemical series is a series that shows the reactivity of the metals. We must note that the order of the reactivity of the metals depends on the electrode potential of the metal. The metals that have a higher electrode potential would tend to react better and faster.

Also note that, the metals that are higher in the electrochemical series are able to displace the metals that are lower in the series from their aqueous solutions. This implies that if we add a metal to a solution that contains a meta that is lower in the electrochemical series, the lower meta is discharged from solution.

As we can see, when we add each of these metals to the iron sulfate solution, the only time that we would be able to have a reaction is when  we add the aluminum or the magnesium metals.

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The second element in group 2 has an atomic number of 12.

We can describe atomic number as the number of protons that are present in the nucleus of an atom. The number of protons is equal to the number of electrons, hence the atomic number is the number of protons or the number of electrons in an atom.

Beryllium has an atomic number of 4 because the element Beryllium has 4 protons.

In the periodic table, you will find that the second element in group 2 is Magenium. The atomic number of Magnesium is 12 because Magnesium has 12 protons in the nucleus of its atom.

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Answer:

Explanation:

so

The percent ionization in the nitrous acid solution is 1.97% before, and 0.0999% after the addition of sodium nitrate, which lowered the ionization 19.7 times.

To calculate percent ionization, we need to use the expression for the acidity constant of nitrous acid:

[tex]Ka = \frac{[H^{+} ][NO_{2} ^{-} ]}{[HNO_{2} ]}[/tex]

Ka - acidity constant (for nitrous acid, 7.1 * 10⁻⁴)

[H⁺] - concentration of H⁺ ions

[NO₂⁻] - concentration of nitrite ions

[HNO₂] - concentration of unionized nitrous acid

[H⁺] = [NO₂⁻]

[HNO₂] = 1.80 M - X

[tex]7.1 * 10^{-4} = \frac{X^{2} }{1.80 - X}[/tex]

When we transform the equation above, we get a quadratic equation:

X² + 7.1 * 10⁻⁴X - 12.78 * 10⁻⁴ = 0

Once we solve for X, we get:

X = 0.0354 M

Because the concentration of H⁺ ions (X) is equal to the concentration of the ionized nitrous acid, the percent ionization will be:

%ion = 100% * X / 1.80 M

%ion = 100% * 0.0354 M / 1.80 M

%ion = 1.97%

The second calculation is actually easier because we can safely assume that, with added sodium nitrite, all nitrite ions come from the salt, and the amount coming from the acid is negligible. With that in mind, the expression for the acidity constant will look like this:

[tex]7.1 * 10^{-4} = \frac{X * 0.71 }{1.80 M - X}[/tex]

When rearranged, we get this equation:

0.71 * X = 12.78 * 10⁻⁴ M - 7.1 * 10⁻⁴X

0.71071 X = 12.78 * 10⁻⁴ M

X = 12.78 * 10⁻⁴ M / 0.71071

X = 0.001798 M

%ion = 100% * 0.001798 M / 1.80 M

%ion = 0.0999%

So the addition of sodium nitrite resulted in 1.97 / 0.0999 = 19.7 times lower ionization of the nitrous acid.

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The frequency of the radiation is 1.6 * 10^15 Hz while its energy is 1.056 * 10^-18 J

Recall that the electromagnetic radiation is commonly called light. All the members of the electromagnetic spectrum are known to have the speed of light which is 3 * 10^8 m/s. The first task that we have is to obtain the frequency of the electromagnetic wave since we have the wavelength of the wave we seek.

Given that;

frequency = Speed of light/ wavelength

Frequency =  3 * 10^8 m/s/193.3 * 10^-9 m

Frequency = 1.6 * 10^15 Hz

Next we need to obtain the energy of the radiation and we have to do that from;

E = hf

E = energy of the photon

h = Planks constant

f = frequency of the photon

E = 6.6 * 10^-34 * 1.6 * 10^15 Hz

E = 1.056 * 10^-18 J

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Answer:

Explanation:

Here, we want to get the vapour pressure of the compound at the given temperature

We can use the Clausius-Clapeyron equation for this

Mathematically, we have this as:

So,let us identify the values:

P1 = 103 mmHg

P2 = ?

ΔH = 28,900

R = 8.31

T1 = 278 K

T2 = 309 K

We now proceed to substitute these values into the equation above as follows:

Answer

a. C₂H₂O + 2O₂ → 2CO₂ + H₂O

b. 8 moles of O₂

c. 64 g of O₂

d. The grams of CO₂ produced is 262 g and the mass of H₂O produced is 53.6 g.

Explanation

a. The balanced chemical equation gasohol is a fuel containing liquid ethanol (C₂H₂O) that burns in oxygen gas to give carbon dioxide and water gases is:

b. The moles of O₂ needed to completely react with 4.0 moles of C₂H₂O?.

The mole ratio of O₂ to C₂H₂O in the balanced equation is 2:1.

Therefore, 4.0 moles of C₂H₂O will completely react with (2 x 4) = 8 moles of O₂.

c. The mass in grams of O₂ that is used up in the reaction if a car produces 88 g of CO₂.

The molar mass of CO₂ = 44.01 g/mol

The molar mass of O₂ = 31.999 g/mol

The mole ratio of O₂ to CO₂ is 2:2

This implies (2 mol x 31.999 g/mol) = 63.998 g of O₂ is used up to produce (2 mol x 44.01 g/mol) = 88.02 g of CO₂

Therefore x g of O₂ will be used up to produce 88 g of CO₂

That is;

Hence, the mass in grams of O₂ that is used up in the reaction if a car produces 88 g of CO₂ is 64 g.

d. The grams of CO₂ and H₂O that can be produced if 125 g of C₂H₂O were burnt.

1 mole of C₂H₂O = 42.04 g

1 mole of CO₂ = 44.01 g

1 mole of H₂O = 18.01 g

Mass of CO₂ produced:

From the balanced, the mole ratio of C₂H₂O to CO₂ is 1:2

The grams of CO₂ produced is 262 g.

Mass of H₂O produced:

From the balanced, the mole ratio of C₂H₂O to H₂O is 1:1

The mass of H₂O produced is 53.6 g

Answer:

Smaller Atomic Radius, High Ionization Affinity, and High Electron Affinity

[Note:  It is Br2, not B2, the bomber]

Explanation:

a) Smaller Atomic Radius  YES  Each of these elements have a high number of electrons that nearly fill the lower energy orbitals, forcing the protons in the nucleus to cluster togeter more tightly.

b) High Metallic Character NO

c) High Ionization Energy    YES  - They want to keep their electrons, so the ionization energy is high.

d) High Electron Affinity  YES  They attract electons from anything that comes nearby.

Answer

AlBr₃ is the limiting reactant

Explanation

Mass of AlBr₃ = 23.45 g

Mole of AlBr₃ = Mass/molar mass = 23.46 g/266.69 g/mol = 0.08797 mol

Mass of Na₂O = 34.57 g

So mole of Na₂O = mass/molar mass = 34.57 g/61.9789 g/mol = 0.5578 mol

Mole ratio of AlBr₃ to Na₂O = (0.08797/0.08797) : (0.05578/0.08797) = 1:6

To know the limiting reactant, write a chemical equation for the reaction and compare the reactant mole ratio in the equation with the mole ratio above.

2AlBr₃ + 3 Na₂O -----> Al₂O₃ + 6NaBr

Mole ratio in the equation = 2:3

Comparing the mole ratio, AlBr₃ will be the first to be completely consumed.

Therefore, AlBr₃ is the limiting reactant