Calculate the change in enthalpy for the following reaction:
4NH3 (g) + 7O2 (g) --> 4 NO2 (g) + 6 H20 (l)
AH NH3= -46
AH4NO2= +34
AH+H200=-286
AH reaction= ____ kJ/mol
Is this reaction endothermic or exothermic?

Answer:

gold and platinum

Explanation:

Very unreactive metals, such as gold and platinum, are found in the Earth's crust as pure metals. These are called native metals.

Answer:

Eventually, these individual laws were combined into a single equation—the ideal gas ... We find that temperature and pressure are linearly related, and if the ... then P and T are directly proportional (again, when volume and moles of gas are ... of the variables, and they are more difficult to use in fitting theoretical equations ...

Explanation:

Answer: steaks

Explanation:

Answer: D

Explanation:

d

The number of moles in 0.025 g of  (NH[tex]_4[/tex])[tex]_2[/tex]Cr[tex]_2[/tex]O[tex]_7[/tex] is 1.0 x 10⁻⁴moles. The word "mole" is shortened to "mol".

A mole is just a measuring scale. In reality, it's one of the International System for Units' seven foundation units (SI). When already-existing units are insufficient, new ones are created. The mole is indeed a SI unit that is used to quantify any quantity of a material. The word "mole" is shortened to "mol". Exact number of particles in one mole is 6.0221407610 23.

The levels at which chemical reactions frequently occur exclude the use of grams, yet utilizing actual numbers of atoms, molecules, or ions would also be unclear. To fill this gap between extremely small and extremely huge numbers, scientists created the mole.

number of mole of (NH[tex]_4[/tex])[tex]_2[/tex]Cr[tex]_2[/tex]O[tex]_7[/tex] = given mass / molar mass

                                                    =  0.025 / 252.07

                                                   =9.91 × 10⁻⁵moles

                                                   =  1.0 x 10⁻⁴moles

Therefore, the correct option is option D

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Answer:

the answer is A don't put b Coz b is incorrect

Answer:

Explanation:

The whole sample is 269

%copper = 127/269 * 100 = 47.2%

%chlorine = 142/269 * 100 = 52.8%

That's all you are asking. Is there more?

Answer:

(1) 4- ethyl -6 methyl -2 octyne

Answer:

The proporties of both rubber and gum.

Explanation:

Answer: You can view more details on each measurement unit:

Explanation:

molecular weight of Hydrogen Fluoride or mol The molecular formula for Hydrogen Fluoride is HF. The SI base unit for amount of substance is the mole. 1 grams Hydrogen Fluoride is equal to 0.049984147027929 mole.

Answer: There are 7.4 moles of helium gas present in a 1.85 liter container at the same temperature and pressure.

Explanation:

Given: [tex]V_{1}[/tex] = 2.25 L,     [tex]n_{1}[/tex] = 9.0 mol

[tex]V_{2}[/tex] = 1.85 L,            [tex]n_{2}[/tex] = ?

Formula used to calculate the moles of helium are as follows.

[tex]\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}\\[/tex]

Substitute the values into above formula as follows.

[tex]\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}\\\frac{2.25 L}{9.0 mol} = \frac{1.85 L}{n_{2}}\\n_{2} = \frac{1.85 L \times 9.0 mol}{2.25 L}\\= 7.4 mol[/tex]

Thus, we can conclude that there are 7.4 moles of helium gas present in a 1.85 liter container at the same temperature and pressure.

Answer:

Because fresh water flowing into the estuary is less salty and less dense than water from the ocean, it often floats on top of the heavier seawater. ... For example, a heavy spring rain, or a sustained shift in local winds, can drastically affect the salinity in different parts of an estuary.

Answer:

Answer:

1.54grams

Explanation:

Molarity of a solution = n/V

Where;

n = number of moles (mol)

V = volume (L)

Based on the information given in this question;

Volume of NaOH solution = 5.0 × 10ml

= 50ml = 50/1000 = 0.050 L

Molarity = 0. 77 M

Using; Molarity = n/V

0.77 = n/0.05

n = 0.77 × 0.05

n = 0.0385mol

To find the mass (grams) of NaOH in the solution, we use the following formula:

mole (n) = mass/molar mass

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

0.0385 = mass/40

mass = 0.0385 × 40

mass = 1.54grams.

Answer:

an orange would be considered a fruit

Explanation:

fruits have seeds while vegetables do not

Answer: IT’S SOLUTION!!

Explanation:

I’m taking ck-12

The carbonated water is a type of solution. The correct option is a.

A solution is a uniform mixture of one or more dissolved solutes in a solvent.

A solvent is a substance that dissolves a solute to produce a homogeneous mixture. The substance that dissolves in a solvent to form a homogeneous mixture is referred to as a solute.

Because carbonated water is a mixture, it contains two or more different chemicals. Carbonated water is made up of both water and carbon dioxide.

The amount of each ingredient in carbonated beverages is fixed. All of the components, such as sweetener, water, and carbon dioxide bubbles, are distributed evenly. Homogenous mixtures are those in which the amount of each component is uniform.

Thus, as in carbonated water, when carbon dioxide bubbles are thoroughly mixed into the water, they become invisible, it can be considered as solution, means option a is correct.

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Answer:

Mass of CaCl2 = 4.1625 grams

Explanation:

We will recall that:

For solution: Molarity = [tex]\dfrac{moles \ of \ solute }{volume \ of \ solution (L)}[/tex]

[tex]1.5 = \dfrac{moles}{0.025 }[/tex]

Moles = 0.0375 moles

Mass = no of moles × molar mass(MM)

Molar mass of CaCl2 = 111 g/mol

Mass = 0.0375 mol × 111 g/mol

Mass of CaCl2 = 4.1625 grams

Answer: The given demonstration does not support Boyle's Law.

Explanation:

According to Boyle's law, at constant temperature the pressure of an ideal gas is inversely proportional to the volume of gas.

[tex]P \propto \frac{1}{V}[/tex]

Therefore, an increase in volume of gas will lead to a decrease in pressure and vice-versa.

Now, according to the given data of volumes there is occurring an increase on moving from final volume 1 to final volume 3. This means that pressure is decreasing.

As a result, if a balloon was squeezed or compressed then it would get smaller. But in the given demonstration pressure is not given.

Thus, we can conclude that the given demonstration does not support Boyle's Law.

Answer:

0.13653499904751903

Explanation:

Convert Units .com

Answer:

yes

Magnesium (Mg) combines with chlorine (Cl2) to form a new product as magnesium chloride (MgCl2). Therfore its a combination reaction and the balanced equation can be written as: Mg(s)+Cl2(g)→MgCl2(s)

Answer:

57.4 g/mol

Explanation:

Step 1: Convert 450 cm³ to L

We will use the conversion factors 1 cm³ = 1 mL and 1000 mL = 1 L.

450 cm³ × 1 mL/1 cm³ × 1 L/1 mL = 0.450 L

Step 2: Convert 23 °C to Kelvin

We will use the following expression.

K = °C + 273.15 = 23 + 273.15 = 296 K

Step 3: Calculate the number of moles of the gas

We will use the ideal gas equation.

P × V = n × R × T

n = P × V / R × T

n = 700 mmHg × 0.450 L / (62.4 mmHg.L/mol.K) × 296 K = 0.0171 mol

Step 4: Calculate the molar mass of the gas

0.982 g of the gas correspond to 0.0171 moles.

M = 0.982 g/0.0171 mol = 57.4 g/mol

Answer:

5.1044844 x 10^7/cm^3 = 5E7

Explanation:

The atomic weight and density (at 25 ° C) for copper are 63.5 g/mol or 0.0635 kg/mol and 8,960 kg/m^3

First lets find the value of N, number of atomic sites per cubic meter for copper, from its atomic weight Acu, its density, and Avogadro’s number NA

N = NA x ρ / Acu = 6.023 x 10^23 x 8,960 kg/m^3 / 0.0635 kg/mol = 8.4985953 x 10^28 atoms / m3

Temperature dependency can be given as :

Arrhenius equation

Nv = N e^(-EA/KT)

N = no. of atoms initially

Ev = activation energy

Nv = 8.4985953 x 10^28 atoms / m^3 exp^-(0.9ev/atom /8.617x10-5 eV/(atom-K) x 298 K

Nv = 5.1044844 x 10^13 /m3

vacancies per cm^3 = 5.1044844 x 10^7/cm^3 = 5E7

Answer:

hope it is helpful to you

Answer:

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Answer:

The pressure will be 0.4 atm.

Explanation:

The gas laws are a set of chemical and physical laws that allow determining the behavior of gases in a closed system. The parameters evaluated in these laws are pressure, volume, temperature and moles.

As the volume increases, the gas particles (atoms or molecules) take longer to reach the walls of the container and therefore collide with them less times per unit of time. This means that the pressure will be lower because it represents the frequency of collisions of the gas against the walls. In this way pressure and volume are related, determining Boyle's law which says:

"The volume occupied by a certain gaseous mass at constant temperature is inversely proportional to pressure"

Boyle's law is expressed mathematically as:

P*V= k

If you initially have the gas at a volume V1 and press P1, when the conditions change to a volume V2 and pressure P2, the following is satisfied:

P1*V1= P2*V2

In this case:

Replacing:

1.2 atm* 4 L= P2* 12 L

Solving:

[tex]P2=\frac{1.2 atm*4 L}{12 L}[/tex]

P2= 0.4 atm

The pressure will be 0.4 atm.

Answer:

Capacity is the amount of liquid a container can hold. Mass is how much space an object takes up.

Explanation:

All the others are incorrect.

Answer:

I believe it's mass? I may be wrong though...

Answer:

Option B. 384 nm

Explanation:

From the question given above, the following data were obtained:

Frequency (f) = 7.81×10¹⁴ Hz

Velocity of photon (v) = 3×10⁸ m/s

Wavelength (λ) =?

The wavelength of the photon can be obtained as follow:

v = λf

3×10⁸ = λ × 7.81×10¹⁴

Divide both side by 7.81×10¹⁴

λ = 3×10⁸ / 7.81×10¹⁴

λ = 3.84×10¯⁷ m

Finally, we shall convert 3.84×10¯⁷ M to nm. This can be obtained as follow:

1×10¯⁹ m = 1 nm

Therefore,

3.84×10¯⁷ m = 3.84×10¯⁷ m × 1 nm / 1×10¯⁹ m

3.84×10¯⁷ m = 384 nm

Thus, the wavelength of the photon is 384 nm

Answer:

B. Heat the solution, dissolve the solute, and let the solution cool verifying nothing settled out.

Explanation:

To dissolve more solute, the solution has been heated at a high temperature, and the cooling has been observed to verify proper dissolution.

The solubility of the compound has been the ability of the solvent to dissolve the solute molecules.  For the solution formation, the intermolecular forces between the solute molecules have been broken in order to sustain the interaction between the solute and the solvent molecules,

The interaction between solute and solvent molecules results in the dissolution of the solute in the solvent.

When Gunther dissolves the 34 grams, of solute, the energy of the solvent molecules has been enough to break the solute interactions and dissolve the solute molecules.

However, in order to dissolve more molecules, the solvent molecules are provided with the energy that has been able to increase the kinetic energy of the solvent for the dissolution of more solute.

The kinetic energy of the solvent has been increased with the increase in the temperature, thereby adding to the more dissolution of the solute.

Thus, to dissolve more solute in the solvent, the solution has been heated at a high temperature, and the cooling has been observed to verify the absence of precipitate thereby proper dissolution.

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