Understanding Rate of Reaction: Exploring Measurement Methods

[LVB]

Rate of reaction helppp !

heyy guys.
I reallyy need help. I am doing my rate of reaction coursework ... nad i am stuck.

I know there are three ways of measuring the rate of a reaction (right ? )
1. weighing the reaction mixture
2. the cross
3. the gas displacement

rightt ... in my coursework i am using
Hydrochloric acid and sodium thiosulphate.

I know that the cross method is the best ... because our teacher told us. But why does the weighing one not work ??

Hopeee you understand what I'm on about. Would be reallyy greatful for your replies. Thank youuu !

 

[LVB]

helpppppppp !

i am reallyy stuck will my coursework.

I am reacting hydrochloric acid with sodium thiosuplahte.

What is wrong with using the gas displacement method ?



Thank you for your help !

 

[Borek]

Please elaborate, no idea what you are writing about.

--

 

[LVB]

I am doing my rate of reaction coursework ... and i am stuck.

I know there are three ways of measuring the rate of a reaction (right ? )
1. weighing the reaction mixture
2. the cross
3. the gas displacement

rightt ... in my coursework i am using
Hydrochloric acid and sodium thiosulphate.

I know that the cross method is the best ... because our teacher told us. But why does the weighing one not work and the displacing the gas one ?

Hopeee you understand what I'm on about. Would be reallyy greatful for your replies. Thank youuu !

 

[Borek]

Three methods? I can think of several others as well.

No idea what cross is.

Do you have something to weight? Or is there a gas between products?

--

 

[Dadface]

heyy guys.
I reallyy need help. I am doing my rate of reaction coursework ... nd i am stuck.

I no there are three ways of measuring the rate of a reaction (right ? )
1. weighing the reaction mixture
2. the cross
3. the gas displacement

rightt ... in my coursework i am using
Hydrochloric acid and sodium thiosulphate.

I no that the cross method is the best ... coz our teacher told us. But why does the weighing one not work ??

Hopeee you understand what I'm on about. Would be reallyy greatful for your replies. Thank youuu !

Hello LVB I am guessing that because of safety constraints it will be difficult to get meaningful results using methods 1 and 3.It is a precipitation reaction so method 2 should be fine.

 

[berkeman]

(merged two threads on the same question)

 

[Dadface]

To clarify LVBs question I think he is investigating the factors that effect the rate of a chemical reaction by looking at the reaction between sodium thiosulphate and hydrochloric acid.The three methods he is referring to are.
1.Measuring the reducing mass as gas is given off.
2.Timing how long it takes for a precipitate to form by timing how long it takes for a mark like a cross to disappear when viewed from above the reaction flask.
3.Measuring the gas volume at regular intervals by ,for example, collecting it in a syringe.

 

[LVB]

yeah that's right dadface. But i want to know why the gas method and the mass method won't work ?
Thank you x

 

[LVB]

i'm reacting hydrochloric acid and sodium thiosulphate.

 

[Dadface]

I am guessing that for safety reasons the acid you will be given will have a low molarity and the gas(sulphur dioxide) will not come off fast enough and in a large enough volume for you to make meaningful measurements in the time you are allowed.In large doses sulphur dioxide is toxic.

 

[LVB]

oh thank you muchly !