I need HELP ASAP PLEASE!!!!!

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

I hope it help u =)

Brainliest answer pls

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.

Answer:

4.002602

Explanation:

Seems Am Converting Between Grams Helium And Mole.

Answer:

Hurricanes and tropical storms gain their power from heated water evaporating from the ocean.

Explanation:

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:

it's non-spontaneous

Explanation:

I hope it helps you

Answer:

oxygen is responsible for rusting

I'm not sure but I think it is C. CrO3

Answer:

The difference is the louder the sound the bigger the waves and your ears collect the sound waves and brings it to you brain

Explanation:

Answer:

Hey! The correct answer is D.) Different vibrations in the ear cause the brain to interpret different sounds.

Explanation:

I got a low score on the test but yeah I got that one correct so It's D

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:

it is in the same phase as the reactants

The  statement describes a homogeneous catalyst is,

So, option B is correct one.

The substance which increases the rate of the reaction without being itself change at the end of the reaction is called catalyst.

learn about homogeneous catalyst,

https://brainly.com/question/4249142

#SPJ2

Answer:

B. crest

Explanation:

The highest part of a wavelength is called the crest, meanwhile, the lowest part is the trough.

Answer:

b

Explanation:

it's highest because it have the most higher wave

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

Answer:

the main cause of pollution is mankinds work like gases and extreme heat caused by factories and cars and littering is also caused by people's careless throwing away so In term man kind is responsible for the pollution

Explanation:

The partial pressure of NO₂ at equilibrium is 0.70 bar and the partial pressure of N₂O₄, at equilibrium is 0.23 bar.

Let x be the mole fraction of NO₂ and x' be the mole fraction of N₂O₄.

The total pressure according to Dalton's law of partial pressure is the sum of the partial pressures of each gas.

Let P be the total pressure of the gases, P' be the partial pressure of NO₂ = 1.4 bar and P" be the partial pressure of N₂O₄ = 0.46 bar.

So, P = P' + P"

= 1.4 bar + 0.46 bar

= 1.86 bar

Since P' = xP

x = P'/P

= 1.4 bar/1.86 bar

= 0.753

Also, P" = xP

x' = P"/P

= 0.46 bar/1.86 bar

= 0.247

Now, since the volume of the container is doubled at constant temperature, we use Boyle's law to determine the new pressure. P₁.

Boyle's law states that the pressure of a given mass of gas is inversely proportional to its volume provided the temperature remains constant. It is written mathematicaly as PV = constant

So, PV = P₁V₁

P₁ = (V/V₁)P

Since V/V₁ = 1/2

P₁ = (V/V₁)P

P₁ = P/2

P₁ = 1.86/2 bar

P₁ = 0.93 bar

So, the new partial pressure of NO₂, P₂ = xP₁

= 0.753 × 0.93 bar

= 0.70 bar

The new partial pressure of N₂O₄, P₃ = x'P₁

= 0.247 × 0.93 bar

= 0.23 bar

So, the partial pressure of NO₂ at equilibrium is 0.70 bar and the partial pressure of N₂O₄, at equilibrium is 0.23 bar.

Learn more about partial pressure here:

https://brainly.com/question/19813237

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:

c)

Explanation:

because alpha particles can go through it

Answer:

beta to Kr-80 or Se-80

Explanation:

sorry if wrong

Answer:

b I think it is the correct answer

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:

Answer:

C

I hope that this helps.

Answer:

i think the answer will be C.

Explanation:

correct me if im wrong

loveya

Answer:

d took the test

Explanation:

Answer:

oxygen carbon hydrogen nitrogen

Explanation:

identified by the number of protons in its atoms

Answer:

I don't know the answers of chemistry if you have an entrance question of maths so I can

[tex]\rule{2000pt}{1000000pt}[/tex]

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

Taking into account the reaction stoichiometry and limiting reagent, 0.7977 grams of KClO₃ are formed from the  reaction of 2.50 g of KClO₄  with 150 mg of FeCl₂  in excess of H₂SO₄.

In first place, the balanced reaction is:

2 FeCl₂ + 13 KClO₄ + H₂SO₄ → 2 Fe(ClO₃)₃ + K₂SO₄ + 11 KClO₃ + H₂O

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

The molar mass of the compounds is:

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:  

The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

To determine the limiting reagent, it is possible to use the reaction stoichiometry of the reaction and a simple rule of three as follows: if by stoichiometry 1801.15 grams of KClO₄ reacts with 253.5 grams of FeCl₂, if 2.50 grams of KClO₄ react how many mass of FeCl₂ will be needed?

[tex]mass of FeCl_{2}=\frac{2.50 grams of KClO_{4} x253.5 grams of FeCl_{2}}{1801.15 grams grams of KClO_{4}}[/tex]

mass of FeCl₂=0.35 grams

But 0.35 grams of FeCl₂ are not available, 150 mg= 0.150 grams (being 1000 mg= 1 grams) are available. Since you have less mass than you need to react with 1801.15 grams of KClO₄, FeCl₂ will be the limiting reagent.

Then the following rule of three can be applied: if by reaction stoichiometry 253.5 grams of  FeCl₂ form 1348.05 grams of KClO₃, 0.150 grams of FeCl₂ form how much mass of KClO₃?

[tex]mass of KClO_{3}=\frac{0.150 grams of FeCl_{2}x1348.05 grams of KClO_{3} }{253.5grams of FeCl_{2} }[/tex]

mass of KClO₃= 0.7977 grams

Then, 0.7977 grams of KClO₃ are formed from the  reaction of 2.50 g of KClO₄  with 150 mg of FeCl₂  in excess of H₂SO₄.  

Learn more about reaction stoichiometry:

Answer:

it is the element cobalt with atomic number 27

I think e no

I am giving you hint