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5V4+ + MnO4– + 8H+ 5V5+ + Mn2+ + 4H2O

What volume of 0.020 mol dm–3 KMnO4 solution is required to oxidise completely a solution containing 0.010 mol of vanadium(IV) ions? WHY IS THE ANSWER 100CM3???????

What volume of 0.020 mol dm–3 KMnO4 solution is required to oxidise completely a solution containing 0.010 mol of vanadium(IV) ions? WHY IS THE ANSWER 100CM3???????

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#2

Molar ratio is 5:1

0.01 / 5 = 0.002 moles of MnO4

So then v=n/c --> 0.002/0.02 = 0.1dm3 --> 100cm3.

0.01 / 5 = 0.002 moles of MnO4

So then v=n/c --> 0.002/0.02 = 0.1dm3 --> 100cm3.

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#3

(Original post by

5V4+ + MnO4– + 8H+ 5V5+ + Mn2+ + 4H2O

What volume of 0.020 mol dm–3 KMnO4 solution is required to oxidise completely a solution containing 0.010 mol of vanadium(IV) ions? WHY IS THE ANSWER 100CM3???????

**usernamenew**)5V4+ + MnO4– + 8H+ 5V5+ + Mn2+ + 4H2O

What volume of 0.020 mol dm–3 KMnO4 solution is required to oxidise completely a solution containing 0.010 mol of vanadium(IV) ions? WHY IS THE ANSWER 100CM3???????

(Don't forget to convert the cm3 to dm3 when using the formula n=cv)

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#4

(Original post by

Molar ratio is 5:1

0.01 / 5 = 0.002 moles of MnO4

So then v=n/c --> 0.002/0.02 = 0.1dm3 --> 100cm3.

**thekidwhogames**)Molar ratio is 5:1

0.01 / 5 = 0.002 moles of MnO4

So then v=n/c --> 0.002/0.02 = 0.1dm3 --> 100cm3.

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#5

(Original post by

We aren't allowed to give complete solutions on TSR

**Rohit_Rocks10**)We aren't allowed to give complete solutions on TSR

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**thekidwhogames**)

Molar ratio is 5:1

0.01 / 5 = 0.002 moles of MnO4

So then v=n/c --> 0.002/0.02 = 0.1dm3 --> 100cm3.

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(Original post by

We aren't allowed to give complete solutions on TSR

**Rohit_Rocks10**)We aren't allowed to give complete solutions on TSR

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#8

(Original post by

thank u so much, can u tell me why u divide by 5 if thats not the mr of V

**usernamenew**)thank u so much, can u tell me why u divide by 5 if thats not the mr of V

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**usernamenew**)

thank u so much, can u tell me why u divide by 5 if thats not the mr of V

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(Original post by

No problem.

**thekidwhogames**)No problem.

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#12

(Original post by

do u mind helping me with another question, i have the answer but since its a multiple choice question, theres no method to show how u get the answer

**usernamenew**)do u mind helping me with another question, i have the answer but since its a multiple choice question, theres no method to show how u get the answer

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(Original post by

I don't mind - go ahead.

**thekidwhogames**)I don't mind - go ahead.

.The removal of silicon dioxide with limestone in the Blast Furnace can be represented by the following equation. CaCO3(s) + SiO2(s) → CaSiO3(l) + CO2(g) The minimum mass of calcium carbonate needed to remove 1.00 tonne (1000 kg) of silicon dioxide is A 0.46 tonne B 0.60 tonne C 1.67 tonne D 2.18 tonne

why is it C 1.67tonne? do u first calculate moles of SiO2?

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#14

(Original post by

thank u!

.The removal of silicon dioxide with limestone in the Blast Furnace can be represented by the following equation. CaCO3(s) + SiO2(s) → CaSiO3(l) + CO2(g) The minimum mass of calcium carbonate needed to remove 1.00 tonne (1000 kg) of silicon dioxide is A 0.46 tonne B 0.60 tonne C 1.67 tonne D 2.18 tonne

why is it C 1.67tonne? do u first calculate moles of SiO2?

**usernamenew**)thank u!

.The removal of silicon dioxide with limestone in the Blast Furnace can be represented by the following equation. CaCO3(s) + SiO2(s) → CaSiO3(l) + CO2(g) The minimum mass of calcium carbonate needed to remove 1.00 tonne (1000 kg) of silicon dioxide is A 0.46 tonne B 0.60 tonne C 1.67 tonne D 2.18 tonne

why is it C 1.67tonne? do u first calculate moles of SiO2?

Let's find number of moles of SiO2:

Find the Mr first --> 60. So moles = mass / Mr = 1,000,000 (grams) / 60 = 50,000/3.

So moles of CaCO3 = 50,000/3 too. We know mass =moles x Mr. Mr of CaCO3 = 40 + 12 + 3(16) = 100 so mass is 100 x 50,000/3 =1,666,666.66... grams which is roughly 1.67 tonnes (divide by 1000 to get into kg and then divide by 1000 to get tonnes).

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(Original post by

First note the molar ratio is 1:1.

Let's find number of moles of SiO2:

Find the Mr first --> 60. So moles = mass / Mr = 1,000,000 (grams) / 60 = 50,000/3.

So moles of CaCO3 = 50,000/3 too. We know mass =moles x Mr. Mr of CaCO3 = 40 + 12 + 3(16) = 1000 so mass is 100 x 50,000/3 =1,666,666.66... grams which is roughly 1.67 tonnes (divide by 1000 to get into kg and then divide by 1000 to get tonnes).

**thekidwhogames**)First note the molar ratio is 1:1.

Let's find number of moles of SiO2:

Find the Mr first --> 60. So moles = mass / Mr = 1,000,000 (grams) / 60 = 50,000/3.

So moles of CaCO3 = 50,000/3 too. We know mass =moles x Mr. Mr of CaCO3 = 40 + 12 + 3(16) = 1000 so mass is 100 x 50,000/3 =1,666,666.66... grams which is roughly 1.67 tonnes (divide by 1000 to get into kg and then divide by 1000 to get tonnes).

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#16

(Original post by

thank u, what i did was find the moles of SiO2 1000000/60.1= 16638.93511 but i didnt use CaCO3, am i supposed to in this case? i just converted it back to the tonnes afterwards

**usernamenew**)thank u, what i did was find the moles of SiO2 1000000/60.1= 16638.93511 but i didnt use CaCO3, am i supposed to in this case? i just converted it back to the tonnes afterwards

What you did was find the moles of SiO2 - this isn't answering the question (to find mass of CaCO3).

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(Original post by

Yes, because that would be wrong. Be careful. You know they have the same number of moles so that's the only thing in common. You have to find the mass of CaCO3 so you need to do moles x Mr so the moles (which you got from SiO2) x Mr (which from the periodic table = 40 + 12 + 3(48)). Then that's your mass - divide by a million (to go from grams to kilograms).

What you did was find the moles of SiO2 - this isn't answering the question (to find mass of CaCO3).

**thekidwhogames**)Yes, because that would be wrong. Be careful. You know they have the same number of moles so that's the only thing in common. You have to find the mass of CaCO3 so you need to do moles x Mr so the moles (which you got from SiO2) x Mr (which from the periodic table = 40 + 12 + 3(48)). Then that's your mass - divide by a million (to go from grams to kilograms).

What you did was find the moles of SiO2 - this isn't answering the question (to find mass of CaCO3).

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#19

(Original post by

thats true, thank u very much for ur help, i really appreciate u taking ur time to explain the answers!

**usernamenew**)thats true, thank u very much for ur help, i really appreciate u taking ur time to explain the answers!

Also, some resources for A level Chemistry (what my brother and I use):

Videos:

https://www.youtube.com/user/MaChemGuy/playlists

http://scienceabove.com/ (has worksheets/ quizzess too)

Questions:

http://scienceabove.com/

https://www.scisheets.co.uk/

http://www.physicsandmathstutor.com

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(Original post by

No problem! Any more help - let me know!

Also, some resources for A level Chemistry (what my brother and I use):

Videos:

https://www.youtube.com/user/MaChemGuy/playlists

http://scienceabove.com/ (has worksheets/ quizzess too)

Questions:

http://scienceabove.com/

https://www.scisheets.co.uk/

http://www.physicsandmathstutor.com

**thekidwhogames**)No problem! Any more help - let me know!

Also, some resources for A level Chemistry (what my brother and I use):

Videos:

https://www.youtube.com/user/MaChemGuy/playlists

http://scienceabove.com/ (has worksheets/ quizzess too)

Questions:

http://scienceabove.com/

https://www.scisheets.co.uk/

http://www.physicsandmathstutor.com

Calculate the percentage abundance of 10B.(the answer is 20% but not sure why)

i know the formula for this but i dont know how to use it when they dont give all the information. do u have to use x and y, 10x+11x/100=10.8?

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