A student thermally decomposed a 0.150 gram sample of impure potassium chlorate. Manganese dioxide was used as a catalyst in the reaction. The student collected 43.60 mL of oxygen gas over water in a eudiometer. Potassium chloride was the other product of the reaction. The temperature and pressure at collection time were 20.00 oC and 762.10 mm Hg respectively. The water level in the eudiometer was 4.22 cm below the outside water level in the beaker.
1) What is the corrected pressure of the dry oxygen gas?
2) What is the volume in mL, of the dry oxygen gas at STP conditions?
3) How many molecules of oxygen were collected?
4) what is the percent purity of the original potassium chlorate sample?

Answers

Answer 1

Answer:

1. Vapor pressure of dry oxygen gas = 747.68 torr

2. Volume at STP = 39.97 mL

3. Number of oxygen gas molecules = 1.074 × 10²¹ molecules

4. Percent purity of KClO3 = 97.3 %

Explanation:

The balanced equation for the reaction is given below :

2 KClO3 (s) ------> 2 KCl (s) + 3 O2 (g)

1) Since the water level in the eudiometer was below the outside water level in the beaker,

Vapor pressure of dry oxygen gas = Total pressure + pressure due to difference in water levels - vapor pressure of water

Vapor pressure of water at 20 °C is 17.535 mm (torr).

Pressure due to difference in water level = 4.22 cm × 10mm/cm / 13.534 (13.534 is the density of mercury) = 3.118 mm (torr).

Vapor pressure of dry oxygen gas = 762.10 torr + 3.118 torr - 17.535 torr

Vapor pressure of dry oxygen gas = 747.68 torr

2) P₁ = 747.68 torr; V₁ = 43.60 ml; T1 = 20 °C + 273.15 = 293.15 K

P₂ = 760 torr; T₂ = 273.15 K; V₂ = ?

Using the general gas equation = P₁V₁/T₁ = P₂V₂/T₂

V2₂= P₁V₁T₂ / P₂T₁

V₂ = (747.68 × 43.60 × 273.15 ) / (760 × 293.15)

V₂ = 39.97 ml

Volume of dry oxygen gas at STP = 39.97 mL

3) Volume of oxygen gas at STP 39.97 mL = 0.03997 L

Number of moles of oxygen gas in 0.03997 L = volume of gas at STP /molarvolume at STP

Number of moles of oxygen gas = 0.03997/22.4 L

Number of molecules of oxygen gas = 0.03997/22.4 L × 6.03 × 10²³ molecules

Number of oxygen gas molecules = 1.074 × 10²¹ molecules

e) Number of moles of oxygen gas = 0.03997/22.4 = 0.001784 moles

From the equation, mole ratio of oxygen gas and potassium chlorate is 3 : 2

Moles KClO3 = 2/3 × 0.001784 moles = 0.001189 moles

Molar mass of KClO3 = 39 + 35.5 + 3 × 16 = 122.5 g

Actual mass of KClO3 decomposed = 122.5 grams × 0.001189 mole = 0.146 grams

Percent purity = (actual mass KClO3 decomposed / sample mass of impure KClO3) × 100%

Percent purity = (0.146/0.150) × 100% = 97.3 %


Related Questions

A 3mL sample of a 200 Molar solution is left open on a lab
counter for two weeks, after which the concentration of the solution is 6 M. What is the new volume of the solution?

Answers

Answer: New volume of the solution is 100 mL.

Explanation:

Given: [tex]V_{1}[/tex] = 3 mL,     [tex]M_{1}[/tex] = 200 M

[tex]M_{2}[/tex] = 6 M,     [tex]V_2[/tex] = ?

Formula used to calculate the new volume of solution is as follows.

[tex]M_{1}V_{1} = M_{2}V_{2}[/tex]

Substitute the values into above formula as follows.

[tex]M_{1}V_{1} = M_{2}V_{2}\\200 M \times 3 mL = 6 M \times V_{2}\\V_{2} = \frac{200 M \times 3 mL}{6 M}\\= 100 mL[/tex]

Thus, we can conclude that new volume of the solution is 100 mL.

How can a cation be formed?
Add 1 clectron
Take away 1 clectron
Add 1 proton
Take away 1 prekon

Answers

Take away 1 electron

Given that the nucleophilic substitution reaction used 5.0 mL of t-pentyl alcohol and 12.0 mL of conc. hydrochloric acid to produce t-pentyl chloride, what is the theoretical yield of t-pentyl chloride, in grams

Answers

Answer:

4.90 g

Explanation:

Given that:

volume of t-pentyl alcohol = 5 mL

the standard density of t-pentyl alcohol = 0.805 g/mL

Recall that:

density = mass(in wt) /volume

mass = density × volume

mass = 0.805 g/mL × 5 mL

mass = 4.03 g

Volume of HCl used = 12 mL

The reaction for this equation is shown in the image attached below.

From the reaction,

88.15 g of t-pentyl alcohol reacts with concentrated HCl to yield 106.59 g pf t-pentyl chloride.

4.03 g of t-pentyl alcohol forms,

[tex]= \dfrac{106.59 \ g \times 4.03 \ g}{88.15 \ g}[/tex] of t-pentyl chloride.

Therefore,

Theoretical yield of t-pentyl chloride = 4.90 g

10. An aqueous solution is made from 0.315 mol of Na,Cr2O7. If the volume of the
solution is .025 L, what is the molarity of the solution? (Answer with significant
digits. Example: 00.0)

Answers

Answer:

Its 12.6M

Explanation:

It came to the conclusion and got these answers

2.22

20.5

10

12.6

12.6 is the correct answer

How do I turn on a Girl???

Answers

Answer:

7 Ways to turn a woman on. ...

Ask her what she likes, and do your homework. ...

Know the three parts of foreplay. ...

Be creative: Not all women are the same. ...

Know her body. ...

Help her feel comfortable receiving oral sex. ...

Play with lube or toys. ...

Remember that great sex won't happen overnight.

Explanation:

Answer: Ask her what she likes, and do your homework. ...

Know the three parts of foreplay. ...

Be creative: Not all women are the same.

Hope this helps

How does sunlight hits earths surface closer to the poles?

Answers

Answer:

When the sun's rays strike Earth's surface near the equator, the incoming solar radiation is more direct (nearly perpendicular or closer to a 90˚ angle). Therefore, the solar radiation is concentrated over a smaller surface area, causing warmer temperatures.

Explanation:

what happens when a star dies

Answers

Answer:

They become a supernova

Explanation:

answer:

a supernova happens and it's quite a beautiful thing. a supernova happens when a star runs out of fuel (hydrogen) and once there isn't any fuel left the star begins to collapse and the outer layer explodes into a supernova. cool right? ( now not all stars explode into supernovas just the red giants. some other stars just fade away.)

explanation:

https://www.sciencefocus.com/space/how-do-stars-die/

good luck :)

i hope this helps

brainliest would be highly appreciated

have a nice day!

(b) How many moles of hydrogen are needed to make 30 moles of Fe?

PLEASE HELP ASAP

Answers

Answer:

1 mole of Fe is 55.85 g per mole

Explanation:

hope it helps

The moles of hydrogen that are needed to make 30 moles of Fe is 45 moles.

What are moles?

Moles is a measurement unit. It is the quantity amount of substance.

The balanced equation is

Fe2O3 + 3H2 ---> 2Fe + 3H2O

Given the moles of iron is 30

To find the moles of hydrogen is?

According to the given balanced equation, the ratio of moles of hydrogen and iron is 3 : 2

To produce 30 moles of Fe

30 x 3 / 2 = 45 moles.

Thus, the number of moles of hydrogen is 45 moles.

To learn more about moles, refer to the link:

https://brainly.com/question/20486415

#SPJ5

Your question is incomplete. Your most probably complete question is given below:

One way to change iron are, Fe2O3, into metallic iron is to heat it together with hydrogen:

Fe2O3 + 3H2 ---> 2Fe + 3H2O

Why is it important that the perodic table is structured as a table rathe than a list of elements. please answer me​

Answers

Answer:

According to the b word, this is the answer

Explanation:

Learning a periodic table is more important as it is systematically arranged to give a lot of information about the elements and the way they relate to each other in various ways. Moreover, chemistry is all more about chemical elements. Hence a good understanding of the chemical elements will discover more about chemistry.

Explain three factors that can affect the size of a line in a spectrum.

Answers

Answer:For atoms and molecules, the width of spectral lines is governed mainly by the broadening of the energy levels of the atoms or molecules during interactions with surrounding particles and by the broadening of the spectral lines as a result of the Doppler effect.

Explanation:

HELP PLISSS !!!!! what did a criminal often use to poison? A. Eye medication. B. potassium cyanide​

Answers

Answer:

potassium cyanide

Explanation:

while eye medications do harm your immune system it is not enough to kill someone. criminals mainly used potassium cyanide because it was cheap. it serves as a substitute for ethanol.

The volume of a gas is 5.0 L, when the temperature is 5.0 degrees Celsius. If the temperature is increased to 10.0 degrees Celsius with no change in pressure, what is the new volume?

Answers

Answer:5.1L

Explanation:

how many atoms are in 14 moles of cadium

Answers

Answer:

14x6.02x10^23=8.428x10^23 atoms

Answer:

atoms are in 14 moles of cadmium. Cadmium is present in some foods and is emitted when fossil fuels like as coal and oil is used, smoking cigarettes. It is used in craft glazes, metal batteries, and coatings. We know that 1 mole of Cadmium (Cd contains) 6.023*1023 atoms, which is Avogadro's number

Explanation:

3. What are the factors needed for phase change to happen?
A. Heat and pressure
C. Sound and radiation
B. Power and radiation
D. Force and velocity​

Answers

Answer:

A. Heat and pressure

Explanation:

 How many moles of ammonium hydroxide are present in 140.0 g of the substance?

Answers

I believe the answer is 18.

How many grams of potassium carbonate are needed to make 300ml of a 4.5M solution?

Answers

Answer:

186.3g

Explanation:

4.5moles of K₂CO₃  is in 1000ml

? moles of K₂CO₃ is in 300 ml

(4.5 × 300)/ 1000 = 1.35 moles of K₂CO₃

1 mole of K₂CO₃ = (39 × 2) + 12 + (16 × 3) = 78 + 12 + 48 = 138g

1.35 moles of K₂CO₃  = ?

= (1.35 × 138)/1 = 186.3g

15.
A tank containing 173 grams of methane, CH (9), registers 15.1 atmospheres at 298 Kelvin. What is the volume of the tank (assuming the entire volume is available to the gas)?
A 3,410L
B. 213
C.O 175L
D. 280.
Chemistry 4/28 5454
Copyright © 2021 Illuminate Education, Inc. All Rig

Answers

Answer: The volume of tank is 17.5 L.

Explanation:

Given: Mass of methane = 173 g

Pressure = 15.1 atm

Temperature = 298 K

Molar mass of methane is 16.04 g/mol.

Therefore, moles of methane are calculated as follows.

[tex]No. of moles = \frac{mass}{molar mass}\\= \frac{173 g}{16.04 g/mol}\\= 10.78 mol[/tex]

Now, ideal gas equation is used to calculate the volume as follows.

PV = nRT

where,

P = pressure

V = volume

n = no. of moles

R = gas constant = 0.0821 L atm/mol K

T = temperature

Substitute the values into above formula as follows.

[tex]PV = nRT\\15.1 atm \times V = 10.78 mol \times 0.0821 L atm/mol K \times 298 K\\V = \frac{10.78 mol \times 0.0821 L atm/mol K \times 298 K}{15.1 atm}\\= 17.5 L[/tex]

Thus, we can conclude that volume of the tank is 17.5 L.

In the formula H2SO4, what is the 4 called?

Answers

Please give me a thanks

Sulfuric acid

Answer:

Well 4 in H2SO4 would be called Sulfuric Acid

Explanation:

The Reason why its called by its name because the form lua is called this its because its a colorless Acid that burns it also has dissolving metals and other stuff inside of it. it has another name called oil of vitriol. hopefully this helps ^^!

How are a desert and a tundra similar?

They both have high levels of precipitation.
They have many trees and a lot of vegetation.
They have high average temperatures.
They have low humidity and low levels of precipitation.

Answers

Answer:

They have low humidity and low levels of precipitation.

Explanation:

Both the desert and the tundra are two extreames, one is really hot while the other is really cold. Deserts only receive less than 300 mm of rain each year. While the tundra receives 150 to 250 mm of precipitation each year, including melted snow. Which is less than the majority of the world's deserts.

Answer: They have low humidity and low levels of precipitation.

Explanation:

Differences: Tundra's are extremely cold, and doesn't get much rain.

Differences: The Dessert is Extremely hot and doesn't get rain.

Explanation: There is already our answer here, If we compare there differences the we will find our answer. This is what I found as the same "doesn't get rain." And we know that precipitation is rain so your answer would be precipitation. Your answer: They have low humidity and low levels of precipitation.

what's the relation between Kp and Kc​

Answers

Answer:

the relation between Kp and Kc is

[tex] \colorbox{red}Kp=Kc{[RT]}^{∆n}[/tex]

where

∆n=no.of moles of gaseous product - no.of moles of gaseous reactant in the balanced chemical equation.

R=universal gas constant

T=temperature.

Bats and marine mammals are able to locate prey and to communicate by sending and receiving sound waves that echo off surface. Echos demonstrates the wave property of A: absorption, B: diffusion, C: transmission, or D: reflection

Answers

I’m pretty sure it’s S
D, since your using echo, it reflects of the object or animal.

Which types of electron orbitals will have a higher energy than a 4 d orbital?

Answers

Answer:

shell

Explanation:

it is because the shell contains many electrons

Which is a LIMIT that authors telling stories using aural media, such as radio plays, must deal with?
A. listeners can hear how each actor says lines of dialogue
B. sound effects can enhance the story's action
C. music can reinforce the story's emotional moments
D. characters thoughts and feelings must be spoken aloud

Answers

I think the answer is D

DESCRIBE HOW THE INTESTINES, LIVER, STOMACH, AND PANCREAS ALL WORK TOGETHERbrainlist if its right and not actually stup/d answers BTW GIVING MY POINTS IF ITS RIGHGT LOTS OF DETAUKL BUT PUT IT IN 5TH GRADE LAUNGE

Answers

They all work together to digest food. The liver aids in bile production which is supplied to the stomach, while the stomach breaks the food down with hydrochloric acid. The pancreas supplies the body with enzymes to break down sugars, starches, and fats. The intestines help move the food out of the body while pulling anything left over such as minerals and water out and converting the food into stool.

Hope this helps!

Answer:

Explanation:

here to give other person brainlist

how do you identify whether a solution is a buffer solution or not

Answers

Answer:

You check whether the PH level changes when you add little amounts of strong acid or base. If you see that there is little to no change in the PH, then it is a buffer solution.

Hope that answers your question

Explanation:

100.0 g of water was placed in a simple, constant-pressure calorimeter. The temperature of the water was recorded as 295.0 K. A 20.0 g copper block was heated to 353.0 K and then dropped into the water in the calorimeter. What was the final temperature of the water if the specific heat capacities of copper is 0.385 J/g K

Answers

Answer:

[tex]296.05\ \text{K}[/tex]

Explanation:

[tex]m_w[/tex] = Mass of water = 100 g

[tex]c_w[/tex] = Specific heat of water = [tex]4.184\ \text{J/g K}[/tex]

[tex]m_c[/tex] = Mass of copper = 20 g

[tex]c_c[/tex] = Specific heat of copper = [tex]0.385\ \text{J/g K}[/tex]

[tex]\Delta T_w[/tex] = Temperature change in water = [tex](T-295)[/tex]

[tex]\Delta T_c[/tex] = Temperature change in cooper = [tex](353-T)[/tex]

T = Final temperature of the system

The heat balance of the system is given by

[tex]m_wc_w\Delta T_w=m_cc_c\Delta T_c\\\Rightarrow 100\times 4.184\times (T-295)=20\times 0.385\times (353-T)\\\Rightarrow 418400\left(T-295\right)=7700\left(353-T\right)\\\Rightarrow 418400T-123428000=2718100-7700T\\\Rightarrow T=\frac{1261461}{4261}\\\Rightarrow T=296.05\ \text{K}[/tex]

The final temperature of the water is [tex]296.05\ \text{K}[/tex].

The final temperature of the water when placed in a calorimeter is 296.05K

HOW TO CALCULATE FINAL TEMPERATURE:

The final temperature of water placed in a calorimeter can be calculated using the following expression:

Q(water) = - Q(copper)

(m × c × ∆T) water = - {m × c × ∆T} copper

Where;

Mass of water = 100 gSpecific heat of water = 4.184 J/g KMass of copper = 20 gSpecific heat of copper = 0.385 J/g KTemperature change in water = T - 295KTemperature change in copper = T - 353K

100 × 4.184 × (T - 295) = - {20 × 0.385 × (T - 353)}

418.4T - 123428 = - (7.7T - 2718.1)

418.4T - 123428 = -7.7T + 2718.1

418.4T + 7.7T = 123428 + 2718.1

426.1T = 126146.1

T = 126146.1 ÷ 426.1

T = 296.05K

Therefore, the final temperature of the water when placed in a calorimeter is 296.05K.

Learn more at: https://brainly.com/question/10987564?referrer=searchResults

Which statement describes the best way to determine how different levels of light affect the growth of seedling plants?

Choose three different light levels, and place four identical plants under each light level to observe the light’s effect on multiple plants.

Choose five different light levels, and place one identical plant under each of the light levels for exactly one week.

Choose four different light levels, and place eight different plant types under the light levels, two under each one, and observe them every day.

Choose one type of light and one type of plant, and then observe the plant for at least four weeks, measuring it each day.

Answers

Answer:

Choose three different light levels, and place four identical plants under each light level to observe the light’s effect on multiple plants.

Explanation:

The Ksp of silver bromide at 25°C (298 K) is 5.0 x 10-13. Write the solubility expression hydrogen oxygen for this compound and show the dissociation equation for AgBr.​

Answers

AgBr(s) <—> Ag+(aq) + Br-(aq)

Ksp = [Ag+][Br-]

250 mL of a solution of calcium oxalate is the evaporated until only a residue of solid calcium
oxalate is left. The mass of the residue recovered from the container was 154 mg. What is the
solubility product of calcium oxalate?

Answers

Answer:

2.3 * 10^-5

Explanation:

Recall that the solubility of a solute is the amount of solute that dissolves in 1 dm^3 or 1000cm^3 of solution.

Hence;

Amount of calcium oxalate = 154 * 10^-3/128.097 g/mol = 1.2 * 10^-3 mols

From the question;

1.2 * 10^-3 mols dissolves in 250 mL

x moles dissolves in 1000mL

x = 1.2 * 10^-3 mols * 1000/250

x= 4.8 * 10^-3 moldm^-3

CaC2O4(s) ------->Ca^2+(aq) + C2O4^2-(aq)

Hence Ksp = [Ca^2+] [C2O4^2-]

Where;

[Ca^2+] = [C2O4^2-] = 4.8 * 10^-3 moldm^-3

Ksp = (4.8 * 10^-3)^2

Ksp = 2.3 * 10^-5

WHAT IS A ROCK?

Please put the answer below


DO ITTT NOWWWWWWWWWWWWWW


|

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Answers

A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition and the way in which it is formed
A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorize by the minerals included, it’s chemical composition and the way in which it is formed.
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