A student was asked to determine the concentration of ammonia, a volatile substance used in the clinical setting as a respiretory stimulant to prevent fainting. First the student pipetted 25.00 mL of the cloudy ammonia solution into a 250.0 mL conical flask. 50.00 mL of 0.100 mol L' HCl(aq) was immediately added to the conical flask which reacted with the ammonia in solution. The excess (unreacted) HCI was then titrated with 0.050 mol L- Na2CO3(aq). 21.50 mL of Na2CO3(aq) was required. Calculate the concentration of the ammonia in the cloudy ammonia solution.​

Answer:

730 N

Explanation:

force =mass×acceleration

force= 73kg × 10 m/s

f=730N

Explanation:

=>7.7 x10¹⁴ to 4.2 x10¹⁴Hz

Answer: B. strontium

Explanation: This is due to electrons being further away from the nucleus in strontium.

This problem is asking for the equilibrium constant at two different temperatures by describing the chemical equilibrium between gaseous nitrogen, oxygen and nitrogen monoxide at 25 °C and 1496 °C as the room temperature and the typical temperature inside the cylinders of a car's engine respectively:

N₂(g) + O₂(g) ⇄ 2 NO(g)

Thus, the calculated equilibrium constants turned out to be 6.19x10⁻³¹ and 9.87x10⁻⁵ at the aforementioned temperatures, respectively, according to the following work:

There is a relationship between the Gibbs free energy, enthalpy and entropy of the reaction, which leads to the equilibrium constant as shown below:

[tex]\Delta _rG=\Delta _rH-T\Delta _rS\\\\\Delta _rG=-RT ln(K)[/tex]

Which means we can calculate the enthalpy and entropy of reaction and subsequently the Gibbs free energy and equilibrium constant. In such a way, we calculate these two as follows, according to the enthalpies of formation and standard entropies of N₂(g), O₂(g) and NO(g) since these are assumed constant along the temperature range:

[tex]\Delta _rH=2*90.25 kJ/mol - (0 kJ/mol+0 kJ/mol)=180.5kJ/mol\\\\\Delta _rS=2*(0.211 kJ/mol*K)-(0.192kJ/mol*K+0.205kJ/mol*K)=0.025kJ/mol*K[/tex]

Then, we calculate the Gibbs free energy of reaction at both 25 °C and 1496 °C:

[tex]\Delta _rG_{25\°C}=180.5-(25+298.15)*0.025=172.42kJ/mol\\\\\Delta _rG_{1496\°C}=180.5-(1496+298.15)*0.025=135.65kJ/mol[/tex]

And finally, the equilibrium constants derived from the general Gibbs equation and Gibbs free energies of reaction:

[tex]K=exp(-\frac{\Delta _rG}{RT} )\\\\K_{25\°C}=exp[-\frac{172420 J/mol}{(8.3145\frac{J}{mol*K})(298.15K)} ]=6.19x10^{-31}\\\\K_{1496\°C}=exp[-\frac{135650J/mol}{(8.3145\frac{J}{mol*K})(1769K)} ]=9.87x10^{-5}[/tex]

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Answer:

8.7 million species

Explanation:

Scientists have estimated that there are around 8.7 million species of plants and animals in existence.

True, the entropy of a perfectly ordered crystalline substance at 0 K is 0 J/mol.

The third law of thermodynamics states that, the entropy of a system approaches a constant value as the temperature of the system approaches absolute zero.

The entropy of any perfectly ordered, crystalline substance at absolute zero temperature is zero.  That is, the entropy of a pure, perfect crystalline substance at 0 K is 0 J/K.

Thus, we can conclude that the given statement is true.  The entropy of a perfectly ordered crystalline substance at 0 K is 0 J/mol.

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The quantity of energy required to heat a piece of iron weighing 1.31 g from 25.0 degrees Celsius to 46.0 degrees Celsius is 2.93 calories.

The ability or power to perform tasks, such as the ability to move an object (having a certain mass) by exerting force.

Energy can exist in many forms, including electrical, mechanical, chemical, thermal, and nuclear, and it can also change its form.

The equation q = mcT, where m is the sample mass, c is the specific heat, and T is the temperature change, can be used to determine the amount of heat acquired or lost by a sample (q).

Q = mcΔT

Q = 1.31 g x 449 x 21° C = 12.26 joule

12.26 /1 x 1 cal / 4.189= 2.93 calories

Therefore, the quantity of energy required to heat a piece of iron is 2.93 cal.

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Answer:

The basic unit of the nervous system is a nerve cell or neuron. The nervous system transmits signals between the brain and the rest of the body, this way, the nervous system's activity controls the ability to move, breathe, see, and think.

Explanation:

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The concentration of NaOH in the reaction can be determined using the Titration method.

The concentration of NaOH in the reaction can be determined by titration.

A burette if filled with the known concentration of H₂SO₄ and then titrated against the known volume of NaOH in a conical flask. An indicator is used in order to determine the end-point of the titration process. At the end-point of the titration, the volume of acid used is recorded.

Next, we will write the balanced chemical equation of the reaction.

The balanced chemical equation for the reaction is

2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O

This means 2 moles of NaOH is required to neutralize 1 mole of H₂SO₄

Now, we can determine the concentration of NaOH by using the titration formula.

[tex]\frac{C_{A}V_{A} }{C_{B}V_{B}} = \frac{n_{A}}{n_{B}}[/tex]

Where [tex]C_{A}[/tex] is the concentration of acid

[tex]V_{A}[/tex] is the volume of acid

[tex]C_{B}[/tex] is the concentration of base

[tex]V_{B}[/tex] is the volume of base

[tex]n_{A}[/tex] is the mole ratio of acid

[tex]n_{B}[/tex] is the mole ratio of base

Then, we put the respective parameters, including the volume of acid determined from the titration process, into the formula to determine the concentration of the NaOH.

Hence, the concentration of NaOH in the reaction can be determined using the Titration method.

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Answer:

bromine

Explanation:

Answer:

He thought he was going to bring Isaac back from the dead. They ended up sacrificing the donkey instead.

The molecule C2F4 has a trigonal planar molecular and electron pair geometry.

The shape of a molecule is dependent on the number of electron pairs that surround the central atom in the molecule. In the molecule C2F4, there are two central carbon atoms.

Each of the central carbon atoms have a trigonal planar molecular and electron pair geometry. C2F4 is a symmetrical molecule so it is nonpolar and has a zero dipole moment.

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Answer:

C 7.5 Moles of MgSO4

Explanation:

Answer:

It would be around 4.4 in PH

Explanation:

I hope this helped.

Answer:

unbalanced force

Explanation:

pls mark me brainliest

Answer:

B. balanced forces

Explanation:

the motion of an object will not change if the forces pushing or pulling the object are balanced

Explanation:

it is a parallel circuit.

hope this helps you.

Answer:

Below

Explanation:

In a chemical reaction, per the law of conservation of mass, no atoms or subatomic particles will be created or destroyed; for example, H2O2 will decompose into H2 and O2, meaning no matter was created or destroyed.

heterotrophs cannot create their own food and rely on others for food

Answer:

Down arrow:

-a car comes to a stop when a traffic light turns red

Up arrow:

-race car accelerates when a race begins

Circle:

-car driving 45 mile per hour down straight road

Explanation:

and i think the car going around a bend would be an up arrow

Explanation:

Which molecule does not obey the Octate rule of valence electrons .

BeCl2

FeCl2

CuCl2

ZnCl2

→BeCl2

Explaination:

BeCl2 violates the octet rule because the boron should be in a suitable valence state such that it binds to 3 chlorines. However, in this molecule boron is associated with six electrons.

Answer:

BeCl2

Explanation:

hope Its useful for you

[tex] \\ \\ [/tex]

kk

c)

)

Na + Mg2+

Na + Mg

Na=

Mg =

=

Zn + CO2-

Zn?- + Co

Zn =

Co=

Answer:

Explanation:

poop

Answer:

la branche de la mécanique concernée par le mouvement des objets sans référence aux forces qui provoquent le mouvement

Answer:

the features or properties of motion in an object.

The new volume when pressure increases to 2,030 kPa is 0.8L

BOYLE'S LAW:

The new volume of a gas can be calculated using Boyle's law equation:

P1V1 = P2V2

Where;

According to this question, a 4.0 L balloon has a pressure of 406 kPa. When the pressure increases to 2,030 kPa, the volume is calculated as:

406 × 4 = 2030 × V2

1624 = 2030V2

V2 = 1624 ÷ 2030

V2 = 0.8L

Therefore, the new volume when pressure increases to 2,030 kPa is 0.8L.

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Answer:

What is nanofluids?

Nanofluids are engineered suspensions of nanometer-sized solid particles in a base fluid. Suspending small solid particles in the energy transmission fluids can improve their thermal conductivity and provides an effective and innovative way to enhance their heat transfer characteristics significantly.

How nanofluids work?

Nanofluid refers to the dispersion of metal or non-metal nano-powder into traditional heat exchange media such as water, alcohol, and oil to prepare a uniform, stable and high thermal conductivity. The traditional heat exchange medium has a low thermal conductivity and has been unable to meet the growing demand for industrial engineering heat exchange. The thermal conductivity of some metal or non-metal nanoparticles is often hundreds of times higher than that of heat-conducting media. For example, common silicon carbide nanoparticles have a thermal conductivity of 170-270 W/m•K. The researchers found that if the nanoparticles can be uniformly and stably dispersed in the heat transfer medium, the thermal conductivity of the nanoparticles will be greatly improved.

Answer:

pairs of electrons

Explanation:

covalent bondin occurs when pairs of electrons are shared by atoms.... nonmetal will readily form covalent bonds with other nonmetal in order to obtain stability.

Answer:

In Homogenous mixtures, the whole mixture is in the same phase whereas in Heterogeneous mixture, substances can be of two phases and layers may separate. ... Homogeneous mixture could be exemplified as a sugar solution or salt solution whereas Mixture of salt and sand could be used as an example of Heterogeneous mixture.

Answer:

Explanation:

Gravity pulls the balls down the ramp, and the force of gravity is bigger on larger-mass objects. The extra force on the bigger ball means that it has more energy when it gets to the bottom of the ramp and consequently travels more before stopping.