Answer to question in picture

Answer:

b I think it is the correct answer

The mass of ammonium chloride that must be added is : ( A ) 4.7 g

Given data :

Volume of water ( V )  = 250 mL = 0.25 L

pH of solution = 4.85

Kb = 1.8 * 10⁻⁵

Kw = 10⁻¹⁴

Given that the dissolution of NH₄Cl gives NH₄⁺⁺ and Cl⁻ ions the equation is written as :

NH₄CI  +  H₂O  ⇄  NH₃ + H₃O⁺

where conc of H₃O⁺

[ H₃O⁺ ] = [tex]\sqrt{Ka.C}[/tex]   and Ka = Kw / Kb

∴ Ka = 5.56 * 10⁻¹⁰

Next step : Determine the concentration of H₃O⁺  in the solution

pH = - log [ H₃O⁺ ] = 4.85

∴ [ H₃O⁺ ] in the solution = 1.14125 * 10⁻⁵

Next step : Determine the concentration of NH₄CI in the solution

C = [ H₃O⁺ ]² / Ka

  = ( 1.14125 * 10⁻⁵ )² /  5.56 * 10⁻¹⁰

  = 0.359 mol / L

Determine the number of moles of NH₄CI in the solution

n = C . V

  = 0.359 mol / L  * 0.25 L =  0.08979 mole

Final step : determine the mass of ammonium chloride that must be added to 250 mL

mass = n * molar mass

         = 0.08979 * 53.5 g/mol

         = 4.80 g  ≈ 4.7 grams

Therefore we can conclude that the mass of ammonium chloride that must be added is 4.7 g

Learn more about ammonium chloride : https://brainly.com/question/13050932

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

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.

Learn more about third law of thermodynamics here: https://brainly.com/question/1156831

Answer:

1) B. determining what data to collect

2) C. Heat samples of water and ethanol in two separate beakers using a Bunsen burner. Measure the temperatures at which the samples boil using a thermometer. Conduct several trials and record the average temperatures as the boiling points.

3) B. Heat energy overcomes the forces of attraction between the molecules of the substance, so the molecules can move more freely.

4). The addition of thermal energy causes the motion of water molecules to overcome electrostatic forces.

Explanation:

I think these are the answers, i'll confirm when I finish the test.

In an experiment it is known what quantity has to measured, thus the measurement of melting point has been determining what data to collect. Thus, Option B is correct.

To investigate the boiling point of water and ethanol, the samples has to boiled at constant parameters and the data has been collected with several trials. Thus, option C is correct.

Melting has been described as the change of the solid to the liquid state. With melting, there has been heat energy higher than the force of attraction allowing the molecules to move freely. Thus, option B is correct.

The boiling has been the change in the water at liquid state to the gaseous state. With boiling there is thermal energy capable of increasing the motion of water molecules overcoming electrostatic force.

For more information about melting, refer to the link:

https://brainly.com/question/12499685

Answer:

A and B.

Explanation:

Climate:

High temperatures and greater rainfall increase the rate of chemical weathering. Lower temperatures can break rocks to by freezing water inside of a rock cracks. When it freezes it expands the water and forces the crack of the rock to expand.

Rock Type:

Certain types of rock are very resistant to weathering. Igneous rocks, especially intrusive igneous rocks such as granite, weather slowly because it is hard for water to penetrate them. Other types of rock, such as limestone, are easily weathered because they dissolve in weak acids.

God had warned Noah of the flood and directed him to build an ark. Noah had faith in God and began building.

Answer:

God Warned Noah for the Flood comindg to Earth to wash away all the bad people's lives and god also said get couple animals girls and boys then build an ark then bring your family and food there to then noah had a faith in god so he obey and start builind the ark in a top of a mountain

Explanation:

Hebrews 11:7

c)

)

Na + Mg2+

Na + Mg

Na=

Mg =

=

Zn + CO2-

Zn?- + Co

Zn =

Co=

Answer:

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

Answer:

oxygen is responsible for rusting

Answer:

Particle collisions cause pressure.

Explanation:

The fast motion of gas particles gives them a relatively large amount of kinetic energy. Recall that kinetic energy is the energy that an object possesses because of its motion. The particles of a gas move in straight-line motion until they collide with another particle or with one of the walls of its container.

Answer:

4.002602

Explanation:

Seems Am Converting Between Grams Helium And Mole.

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

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.

To learn more about energy, refer to the link:

https://brainly.com/question/22920370

#SPJ2

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.

Learn more: https://brainly.com/question/7558603

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.

Learn more about Boyle's law calculations at: https://brainly.com/question/1437490?referrer=searchResults

Answer:

8.7 million species

Explanation:

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

Answer:

yes here is the answer key

for the last question it is a challenge question, here is the answer:

(A) The mass of the cart is 1.214 kg

(B) The mass of one fan is 1.262 kg

(C) The mass of one of the draggable mass units is 3.131 kg

Explanation:

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.

Answer:

730 N

Explanation:

force =mass×acceleration

force= 73kg × 10 m/s

f=730N

Answer:

bromine

Explanation:

This question is describing two chemical equations whereby the concentration of ammonia has to be determined. The first reaction is between 25.00 mL of ammonia and 50.00 mL of 0.100-M HCl whose excess was neutralized with 21.50 mL of 0.050-M Na₂CO₃ and thus, the concentration ammonia in the cloudy solution was determined as 0.114 M.

First of all we need to go over the titration of the excess HCl with Na₂CO₃ by writing the chemical equation it takes place when they react:

[tex]2HCl+Na_2CO_3\rightarrow 2NaCl+CO_2+H_2O[/tex]

Whereas the mole ratio of HCl to Na₂CO₃ is 2:1 and the volume of the HCl leftover is determined as follows:

[tex]V_{HCl}^{leftover}=\frac{2*0.050M*21.50mL}{0.100M} =21.5mL[/tex]

Next, we infer that the consumed volume of HCl by the ammonia solution was:

[tex]V_{HCl}^{consumed}=50.00mL-21.50mL=28.5 mL[/tex]

Then, we write the chemical equation that takes place between ammonia and HCl:

[tex]HCl+NH_3\rightarrow NH_4Cl[/tex]

Whereas the mole ratio is now 1:1, which means that the concentration of ammonia was:

[tex]M_{NH_3}=\frac{28.5mL*0.100M}{25.00mL}\\\\ M_{NH_3}=0.114M[/tex]

Learn more:

I think e no

I am giving you hint

Answer:

The basis for incomplete combustion is that instead of carbon dioxide being produced alongside water, carbon monoxide and carbon is produced instead, the carbon being released as soot. That handily sets the products up for the equation.

And combustion is simply a reaction between a fuel, in this case, methanol and oxygen.

The chemical formula for methanol is CH3OH. Simply write the reactants and products as a chemical equation and balance it, and you have the equation.

Explanation:

Answer:

d took the test

Explanation:

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.

Learn more on titration here: https://brainly.com/question/25290615

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