### Unit of specific rate

Posted:

**Fri Dec 02, 2011 3:56 pm**Hello,

I have a little problem with the unit of the specific rate.

I modeled kinetically limitted gypsum dissolution in a 25 cm column in HP1.

Choosen units in HP1:

Length in [cm]

Time in [h]

Concentrations in [mmol/kgw]

My rate expressions is:

RATES

Gypsum

-start

10 A = parm(1) #surface area

20 V = parm(2) #volume

25 k = parm(3) #specific rate

30 sr_gypsum = SR("Gypsum")

40 rate = k * (A/V) *(1 - sr_gypsum) * m/m0

50 moles = rate * time

60 save moles

-end

I entered a value of 2*10^-5 for the specific rate (parm 3). Now I am not sure if the unit of k*(A/V) is [mmol/(cm?*h)] or [mmol/(L*h)] (L for liter)?

Does the information given suffice to answer the question?

Kind regards

Horst Schonsky

I have a little problem with the unit of the specific rate.

I modeled kinetically limitted gypsum dissolution in a 25 cm column in HP1.

Choosen units in HP1:

Length in [cm]

Time in [h]

Concentrations in [mmol/kgw]

My rate expressions is:

RATES

Gypsum

-start

10 A = parm(1) #surface area

20 V = parm(2) #volume

25 k = parm(3) #specific rate

30 sr_gypsum = SR("Gypsum")

40 rate = k * (A/V) *(1 - sr_gypsum) * m/m0

50 moles = rate * time

60 save moles

-end

I entered a value of 2*10^-5 for the specific rate (parm 3). Now I am not sure if the unit of k*(A/V) is [mmol/(cm?*h)] or [mmol/(L*h)] (L for liter)?

Does the information given suffice to answer the question?

Kind regards

Horst Schonsky