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
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An electrolysis reaction is
A) spontaneous
B) exothermic
C) non-spontaneous
D) hydrophobic
Answer:
it's non-spontaneous
Explanation:
I hope it helps you
2.
The highest part of the wave is called the ____________.
Group of answer choices
A. best
B. crest
C. top
D. trough
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
Van der Waals bonds initiate
a) Between non-metals
b) Within ionic binds
c) Between metals
d) With H-bond
e) All of the above
I think e no
I am giving you hint
calculate the number of molecules in 4.48dm3 of hydrogen at STP
Answer: 1 more of hydrogen =22.4dm3
X moles of hydrogen =4.48dm3
22.4dm3x = 4.48dm3
4.48dm3\22.4dm3
X=0.2 moles
Explanation: 1 volume of hydrogen at STP is 22.4dm3
Hello do anyone on here no something about Gizmos Fan Cart Physics?
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:
what is the result of collisions of particles with an object? *
A. pressure on the object
B. pressure away from the object
C. the object gets lighter
D. the object gets heavier
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.
At a certain temperature, the equilibrium pressures of NO2 and N2O4 are 1.4 bar and 0.46 bar, respectively. If the volume of the container is doubled at constant temperature, what would be the partial pressures of the gases when equilibrium is re-established?
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.
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which is the compound that has the higher boiling point and explain why we see the
differences we do
a. ethane vs. ethene
b. heptyne vs. pentyne
c. octane vs. octanal
thanks!
Answer:
b I think it is the correct answer
Safety considerations
• Sodium Hydroxide (please insert one statement of caution from MSDS)
Answer:
d took the test
Explanation:
Equation for the incomplete combustion of methanol
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:
Which of the following statements is true about CO?
а
The carbon and oxygen share electrons.
b
Carbon is the cation and oxygen is the anion.
с
It is the element cobalt.
d
Its name is monocarbon monoxide.
e
none of these
Answer:
it is the element cobalt with atomic number 27
iDENTIFY THE NAME OF THE ELEMENTS OF THE ATOMS ABOVE
Answer:
oxygen carbon hydrogen nitrogen
Explanation:
identified by the number of protons in its atoms
As part of an investigation into the strength of electrostatic forces between molecules of water, a student will measure the melting point temperature. Which part of the experimental design does this describe?(1 point)
determining the procedure
determining what data to collect
deciding on the appropriate equipment
deciding on the number of trials to perform
Which experimental design would be best to use in investigating the boiling points of water and ethanol?
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. Record these temperatures as the boiling points.
Mix samples of water and ethanol in a beaker, then heat using a Bunsen burner. Measure the temperature at which the sample boils using a thermometer. Record this temperature as the boiling point.
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.
Mix samples of water and ethanol in a beaker, then heat using a Bunsen burner. Measure the temperature at which the sample boils using a thermometer. Conduct several trials and record the average temperature as the boiling point.
Which change happens when a substance melts?(1 point)
The vibration of the molecules produces enough heat to weaken the forces of attraction between the molecules of the substance.
Heat energy overcomes the forces of attraction between the molecules of the substance, so the molecules can move more freely.
Heat energy forces the molecules of the substance farther apart until the rigid structure of the solid breaks.
The molecules of the substance move farther apart, which pulls on the intermolecular bonds between them.
Which change occurs to cause water to boil into steam?(1 point)
The addition of kinetic energy causes the motion of water molecules to overcome gravitational forces.
The addition of kinetic energy causes the motion of water molecules to overcome gravitational forces.
The removal of kinetic energy causes the motion of water molecules to overcome electrostatic forces.
The removal of thermal energy causes the motion of water molecules to overcome gravitational forces.
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:
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Which statement describes a homogeneous catalyst?
It is in a gaseous phase only.
It is in the same phase as the reactants.
It is completely consumed by reactants.
It forms different products than the uncatalyzed reaction forms.
Answer:
it is in the same phase as the reactants
The statement describes a homogeneous catalyst is,
It is in the same as the reactants.So, option B is correct one.
What is homogeneous catalyst?The homogeneous catalyst is refer to catalytic system.In this, the phase of substrates for a reaction and catalytic components are same.Mainly it is in liquid phase.Example: Production of acetic acidWhat is catalyst?
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,
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#SPJ2
Explain the verse below in your own words in a little summary.
Hebrews 11:7
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
How many moles does 205 g of helium,He, contain ?
Answer:
4.002602
Explanation:
Seems Am Converting Between Grams Helium And Mole.
please explain me answer a b c d
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]
Which are the two key factors that affect the rate of weathering of rocks?
Select 2.
A Climate
B Rock Type
C Bedrock
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.
The results of Rutherford's gold foil experiment gave him the evidence to conclude that the center of an atom was A) called the nucleus. B) neutral and relatively small. C) positively charged and relatively small. D) a densely packed area containing both positive and negative particles.
Answer:
c)
Explanation:
because alpha particles can go through it
What does Bromine-80 decays by beta decay to?
Answer:
beta to Kr-80 or Se-80
Explanation:
sorry if wrong
How does the water cycle contribute to the "brown ocean" effect?
Answer:
Hurricanes and tropical storms gain their power from heated water evaporating from the ocean.
Explanation:
Brown Water Effect The brown ocean effect is an observed weather phenomenon involving some tropical cyclones after landfall. Normally, hurricanes and tropical storms lose strength when they make landfall, but when the brown ocean effect is in play, tropical cyclones maintain strength or even intensify over land surfaces.2 FeCl2
+ 13 KClO4
+ H2
SO4
→ 2 Fe(ClO3
)3
+
K2
SO4
+ 11 KClO3
+ H2
O
Calculate the grams of KClO3
arising from the
reaction of 2.50 g of KClO4
with 150 mg of FeCl2
in excess of H2
SO4
.
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:
FeCl₂: 2 molesKClO₄: 13 moles H₂SO₄: 1 moleFe(ClO₃)₃: 2 moles K₂SO₄: 1 mole KClO₃: 11 moles H₂O: 1 moleThe molar mass of the compounds is:
FeCl₂: 126.75 g/moleKClO₄: 138.55 g/mole H₂SO₄: 98 g/moleFe(ClO₃)₃: 306.2 g/moleK₂SO₄: 174.2 g/moleKClO₃: 122.55 g/moleH₂O: 18 g/moleThen, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:
FeCl₂: 2 moles× 126.75 g/mole= 253.5 gramsKClO₄: 13 moles× 138.55 g/mol= 1801.15 grams H₂SO₄: 1 mole× 98 g/mole= 98 gramsFe(ClO₃)₃: 2 moles× 306.2 g/mole= 612.4 gramsK₂SO₄: 1 mole× 174.2 g/mole= 174.2 gramsKClO₃: 11 moles× 122.55 g/mole= 1348.05 gramsH₂O: 1 mole× 18 g/mole= 18 grams
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:
brainly.com/question/24741074 brainly.com/question/24653699 brainly.com/question/23871710What are the five different types of leaves? Subject: science
Answer:
Needle and Scale Leaves. This kind of leaves are mostly found in 'evergreen' trees. ...
Lanceolate Leaf. ...
Oblong Leaf. ...
Linear Leaves. ...
Cordate Leaves.
Explanation:
Answer:
Broad
Flat Leaves.
Needle and Scale Leaves.
Oblong Leaf.
Cordate Leaves.
Explanation:
Which of these objects will most likely float?
Answer:
plastic,palstic bottle,balloon,cap of water bottle,plastic slippers and plastic comb.
Explanation:
hope it helps :D
Which best explains why a person can tell the difference between a whisper and a yell?
O Sound waves turn into chemical signals that indicate certain sounds.
Different vibrations in the ear cause the bras o interpret different sounds.
The fluid in the cochlea picks up electrical signals for the intensity of sound.
The eyes see what is making the noise and help the brain process the sound.
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
Could a single person or animal be a point source pollution
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:
help plzzzzzzzzzzzzzzzzz
Answer:
C
I hope that this helps.
A 4.190 g sample of an oxide of chromium contains 2.179g of chromium, what is its empirical formula?
a. CrO2
b. Cr2O
c. CrO3
d. Cr2O3
I'm not sure but I think it is C. CrO3
Consider the chemical formula for calcium chlorate: Ca(ClO3)2
How many of each of these atoms is in a molecule of calcium chlorate?
I hope it help u =)
Brainliest answer pls
Need ASAP will give brainlist
Answer:
i think the answer will be C.
Explanation:
correct me if im wrong
loveya