# chemical reaction

1. ### Energy of a chemical reaction

Hi all, Is this energy equation of any meaning if there is no chemical reaction $$\triangle G= RT ln \frac{C_1}{C_2}$$ in compartments with concentrations $$C_1 \ and \ C_2$$ Thanks.
2. ### Chemical reaction engineering

What is the definition of rate $(-r_a)=-\frac{dCa}{dt}$ or $(-r_a)=-1/V\frac{dNa}{dt}$ ? I think the general one is the second one and first one is for constant volume reaction system. Is the above written rate equation only valid to batch reactor? If not can we use this in a PFR or MFR? In...
3. ### How can I understand a chemical reaction?

I’m a high school student, I generally get problem in chemical reactions. I understand all physical and chemical properties of a compound, for example carboxylic acid have all the acidic property and aldehydes are highly polar. But the problem comes in chemical reactions like shift of positive...
4. ### I 1st law of thermodynamics with chemical reaction?

$dU = dw + dq$ vs $dU = dw + dq + µdN$ Which equation do we apply to a closed system involving chemical reaction? According to textbooks, the first equation holds for any closed system in the absence of fields and kinetic energy. However, later chapters use the second equation for...
5. ### Water sometimes drips from the exhaust of a running car...

Homework Statement You may have noticed that water sometimes drips from the exhaust of a car as it is running. Is this evidence that there is at least a small amount of water originally present in the gasoline? Homework Equations not sure if there is one. The Attempt at a Solution I'm not...
6. B

### Combustion of Toluene with 30% excess air (Himmelblau)

Homework Statement Toluene, C7H8, is burned with 30% excess air. A bad burner cause 15% of the carbon to form soot (pure C) deposited on the walls of the furnace, what is the Orsat analysis of the gases leaving the furnace? Homework Equations C7H8 + 9 O2 => 7 CO2 + 4 H2O 30% excess of air...
7. ### Do exactly the same chemicals react with each other

Not sure if this is well know but for some reason, I don't know if exactly same chemicals make chemical reactions with one another and if yes, how common that is?
8. ### Is there any chemical reaction with 0 time?

One that occurs immediatly?
9. ### Sodium Fluoride Reaction

I have been reading about how NaOH (Sodium Hydroxide) reacting with HF (Hydrofluoric Acid) yields the products H20 (Water) and NaF (Sodium Fluoride). If I were to do this, would I need the EXACT same quantity of NaOH as HF to get H20 and NaF?
10. ### Wolfram Alpha for Chemistry

Dear PF Forum, Do anybody know the 'Wolfram Alpha' for chemistry? For example. If I enter: HCl + NaOH The website will produce something like HCl + NaOH -> NaCl + H2O (+ or - energy would be preferable) or if I enter: C6H12O6 + O2 The website will produce something like: Do you mean: C6H12O6 +...
11. ### Diffusion -- Tarnishing of metal surfaces

Homework Statement Problem 18B.13 from Transport Phenomena, BSL. Tarnishing of metal surfaces. In the oxidation of most metals the volume of oxide produced is greater than that of the metal consumed. This oxide thus tends to form a compact film, effectively insulating the oxygen and metal from...
12. ### Pyrite roasting -- Mass balance with chemical reaction

Homework Statement A certain pyrite ore contains 85% of FeS2 and 15% of inerts. This ore is introduced into a roasting furnace with 20% excess air, in order to oxidize the FeS2 in the reaction: \textrm{FeS}_2 + \frac{11}{4}\textrm{O}_2 \rightarrow \frac{1}{2}\textrm{Fe}_2 \textrm{O}_3 +...
13. ### Chemical formulas

This is a very basic question. When I see a chemical formula, like for example combustion of methane: $CH_4+2O_2->CO_2+2H_20$ and I compute the standard enthalpy of reaction $H_r$, do I have always to think about this value $H$ and about the chemical reaction as describing a "certain amount"...
14. ### Enthalpy balance equation

Hello PF! I have a very short question. We're currently doing enthalpy balances for chemical reactions in our Thermo class. We are using the simple enthalpy balance equation: \Delta H_{\textrm{Reaction}}^0 = \sum \Delta H_{\textrm{Products}}^0 - \sum \Delta H_{\textrm{Reactants}}^0 My question...