# Rate Equation using a catalystWatch

Announcements
#1
Hey guys,

I'm currently doing my Salters A2 Chemistry Project on the catalytic decomposition of Hydrogen Peroxide, using Manganese(IV) Oxide and Lead(IV) Oxide catalysts.

The rate equations determined by my results have come out as:

Rate = k[H2O2][MnO2]
Rate = k[H2O2][PbO2]

I'm going to calculate the rate constant k by substituting in my values for rate calculated and concentrations used at 20 degrees celcius, however I have a small question.

When substituting my values of catalysts, can I use the value as the mass of catalyst used, for example 1 gram, or do I need to convert the mass used in to a molar value, i.e. using n = m/mr ?

Any help would greatly be appreciated!
0
5 years ago
#2
(Original post by matt_drummer123)
Hey guys,

I'm currently doing my Salters A2 Chemistry Project on the catalytic decomposition of Hydrogen Peroxide, using Manganese(IV) Oxide and Lead(IV) Oxide catalysts.

The rate equations determined by my results have come out as:

Rate = k[H2O2][MnO2]
Rate = k[H2O2][PbO2]

I'm going to calculate the rate constant k by substituting in my values for rate calculated and concentrations used at 20 degrees celcius, however I have a small question.

When substituting my values of catalysts, can I use the value as the mass of catalyst used, for example 1 gram, or do I need to convert the mass used in to a molar value, i.e. using n = m/mr ?

Any help would greatly be appreciated!
You cannot include heterogeneous materials in the rate equation. They can't have a concentration ...
0
#3
They can't have a molar value?

Can't I use n = m/mr i.e. n = 1(gram) / 239.2 (PbO2) = 4.181x10^-3 moldm^-3?

The catalysts have to be involved in increasing the rate of reaction - how can I evaluate this without using a rate equation?
0
5 years ago
#4
(Original post by matt_drummer123)
They can't have a molar value?

Can't I use n = m/mr i.e. n = 1(gram) / 239.2 (PbO2) = 4.181x10^-3 moldm^-3?

The catalysts have to be involved in increasing the rate of reaction - how can I evaluate this without using a rate equation?
The definition of the rate equation requires concentrations. For this the components must be dissolved evenly i.e. homogeneous in the mixture.

You can produce other dependencies of rate on mass of catalysts, but it is not a rate equation.
0
X

new posts
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### University open days

• SOAS University of London
Wed, 29 May '19
• University of Exeter
Thu, 30 May '19
• Cranfield University
Cranfield Forensic MSc Programme Open Day Postgraduate
Fri, 31 May '19

### Poll

Join the discussion

Loved the paper - Feeling positive (191)
22.66%
The paper was reasonable (389)
46.14%
Not feeling great about that exam... (156)
18.51%
It was TERRIBLE (107)
12.69%