Another Chem question. (1 Viewer)

[Mr_Kap]

CO2(aq) + H2O(l) ⇌ H2CO3(aq)

Do we have to know why this happens?

 

[Mr_Kap]

Or just memorise it?

 

[Drsoccerball]

Or just memorise it?

Memorise

 

[enigma_1]

Yeah you needa know. The carbonic acid equilirbium you have to be able to explain it in terms of le chateliers principle and u have to use it in your responses

 

[Mr_Kap]

And with the acid rain equations:

S + O2 --> SO2
SO2 + H2O <--> H2SO3

Now this last part is the part i'm confused with when forming sulfuric acid.
Do we do this: 2H2SO3 + O2 --> 2H2SO4 (and is this meant to be equillibrium)?

OR

this:

2SO2 + O2 --> 2SO3
SO3 + H2O --> H2SO4
and are these meant to be equilibrium?


I am so confused...

 

[Drsoccerball]

And with the acid rain equations:

S + O2 --> SO2
SO2 + H2O <--> H2SO3

Now this last part is the part i'm confused with when forming sulfuric acid.
Do we do this: 2H2SO3 + O2 --> 2H2SO4 (and is this meant to be equillibrium)?

OR

this:

2SO2 + O2 --> 2SO3
SO3 + H2O --> H2SO4
and are these meant to be equilibrium?


I am so confused...

You dont have to show the conversion into sulfuric acid... sulfourous acid is enough since itself is acidic thus proving your point.

 

[Anthel]

You probably also need to know the prac associated that equation. The practical is the decarbonate soft drink prac its in the chemistry syllabus

Identify data, plan and perform a first-hand investigation to decarbonate softdrink and gather data to measure the mass changes involved and calculate thevolume of gas released at 25◦C and 100kPa

 

[Mr_Kap]

Yeah you needa know. The carbonic acid equilirbium you have to be able to explain it in terms of le chateliers principle and u have to use it in your responses

Yeh i can do all that. Was just wondering if we learn it like magic though. Thx.

 

[Kaido]

There is a huge misconception about the Soft drink experiment. Most schools perform it incorrectly, so you should prob look into it

 

[Mr_Kap]

There is a huge misconception about the Soft drink experiment. Most schools perform it incorrectly, so you should prob look into it

WHat misconception?

 

[Crisium]

Here are some things from my practical notes:

Method of Carbon Dioxide Release Acceleration 1: Warming the Drink

• Since this reaction is exothermic, by increasing the temperature, equilibrium will shift to the left to counteract the change, thus producing more carbon dioxide. Furthermore, higher temperatures generally allow for chemical reactions to be carried out at a faster rate (i.e. Kinetic Considerations)

• The drink must be warmed to a temperature below that of its boiling point, and can be done so by placing the beaker in a hot water bath.

• There will be evaporation of the drink, so to account for the loss in the mass of the drink, place water of equal mass to that of the drink into a separate beaker and heat that beaker to the same temperature, and record the amount of water lost through evaporation. The value found from the evaporation of water in the other beaker can be used for the value of the carbonated drink evaporated during the warming process. This is because carbonated drinks are usually composed of 90% water and of 10% additives.

Method of Carbon Dioxide Release Acceleration 2: Adding NaCl

• Add two teaspoons of NaCl to the drink.

• The NaCl will dissolve, releasing more carbon dioxide.

Other Stuff to Know:

• When pouring the contents of the can into the beaker, the entirety of the contents may not have been poured out.

• The time allowed for the carbon dioxide gas to be released may have been insufficient, since nothing was done in order to increase the rate at which the carbon dioxide was released.

• There was the assumption that the results for one brand of soft drink was accepted to be true for other brands.

 

[iforgotmyname]

Its what happens in coke bottles.

If you open the lid, the pressure decreases therefore the backward reaction with co(g) is favoured. This is why you hear that pissss sound

If you shake the lid you increase the pressure. Therefore if you open the bottle under high pressure, all of the pressure is gonna be gone therefore backward reaction is furthered favoured causing the coke the spray out as the gas leaves the chamber.

Coke factories/ produces always recommend you to freeze the coke before serving because forward reaction (H2CO3) is exothermic therefore cooling ie taking away heat, will cause the forward to be favoured and coke tastes better cause more co2 is dissolved in it

 

[iforgotmyname]

And with the acid rain equations:

S + O2 --> SO2
SO2 + H2O <--> H2SO3

Now this last part is the part i'm confused with when forming sulfuric acid.
Do we do this: 2H2SO3 + O2 --> 2H2SO4 (and is this meant to be equillibrium)?

OR

this:

2SO2 + O2 --> 2SO3
SO3 + H2O --> H2SO4
and are these meant to be equilibrium?


I am so confused...

Oh yeah, btw the sulfuric acid made from

SO3 + H2O = H2SO4

is sort of diluted cause water is involved.

 

[Mr_Kap]

Another Question:

Is this CORRECT?

2NO2 (g) + H2O (l) --> HNO3 (aq) + HNO2 (aq) (nitric and nitrous acid) ---------Ahmad Shah Notes had this

or is it this:

3NO2 (g) + H2O (l) --> 2HNO3 (aq) + NO(g) --------- Matrix Education had this...... https://www.matrix.edu.au/chemical-reactions-year-12-chemistry-students-must-know/


Which is it?

 

[Mr_Kap]

im pretty confused.

 

[Crisium]

Another Question:

Is this CORRECT?

2NO2 (g) + H2O (l) --> HNO3 (aq) + HNO2 (aq) (nitric and nitrous acid) ---------Ahmad Shah Notes had this

or is it this:

3NO2 (g) + H2O (l) --> 2HNO3 (aq) + NO(g) --------- Matrix Education had this...... https://www.matrix.edu.au/chemical-reactions-year-12-chemistry-students-must-know/


Which is it?

The top one is preferred

 

[sharoooooo]

it just happens like that.
Memorising it shouldn't be too hard since its just combining them both into one