# Questions tagged [calorimetry]

For questions related to measuring changes in state variables (such as enthalpy) use with the [experimental-chemistry] tag.

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### What are the key differences between combustion of starch and sugar

I performed an energy content experiment the other day using a rudimentary bomb calorimeter. The experiment was comparing for the energy release of a sugary food (Arnott's Tiny Teddies) to the energy ...
27 views

### How does one obtain K and stoichiometry from the Isothermal Calorimetry binding curve?

In Isothermal Calorimetry, I can appreciate that data is fitted to equations to obtain $K, \Delta H, \Delta G, \Delta S$ and stoichiometry, $n$. However, I have seen from multiple sources that $K$ and ...
52 views

### How is temperature inside a bomb calorimeter constant?

I've looked around and have been unable to find an answer. When determining molar reaction enthalpy, you first perform the reaction in the steel bomb then measure the temperature change of the water ...
157 views

### Why is there internal energy change in a bomb calorimeter?

In a bomb calorimeter, the reaction occurs at a constant volume, hence we say that the heat absorbed by the water in the surroundings is equal to the change in internal energy for the reaction. But, ...
94 views

### How does Hess' Law work exactly? [closed]

So I am talking about complicated compounds and not simple reactions where you subtract heats of formation. I was trying to find the heat of reaction for an aryl substituted methyl aryl sulfide being ...
1 vote
97 views

### Help understanding Isothermal titration calorimetry ITC

Trying to understand Isothermal titration calorimetry: ITC , from a public online forum (Off-topic question related to ITC binding studies) I got this question: We performed an ITC binding study (...
32 views

### Is the cell in an isothermal titration calorimeter open to the atmosphere? [closed]

I'm just trying to understand how they can model an isochoric process.
85 views

### Calorimetry- Calculating change in temperature help [closed]

The reaction: Zn(s) + 2 AgNO3 (aq) → 2 Ag(s) + Zn(NO3)2 (aq) takes place in a calorimeter. 30 cm3 of a 1.20 mol dm−3 solution of silver nitrate with an excess of zinc is used. If the value of ∆rH is −...
211 views

### Is it possible to measure the entropy of a chemical reaction through calorimetry?

My broad question is how do you measure entropy change? I was doing a bit of digging into how thermodynamic tables are developed at I got this from NIST. Basically it seems like you need to indirectly ...
4k views

### When to include the mass of the dissolved substance in calorimetry problems?

In some calorimetry problems, in which a substance is dissolved in water and we want the heat of the reaction, the mass of the dissolved substance is included in the mass plugged into mcat but other ...
33 views

### Question on the formula to calculate enthalpy change from calometric data

I have a sample question here. "In an experiment, a student placed 20cm^3 of a solution containing 0.04 mol of HCl in a plastic cup and added 20cm^3 of solution containing 0.04 mol of Na2CO3. The ...
154 views

### How does the calorimeter affect heat released by the system (q)? [closed]

Here are the 2 questions I am pondering about How would the calculated quantity of heat (q) released by a system differ if the calorimeter's heat capacity was taken into account? My thought process ...
1 vote
29 views

### Thermochemistry: On Units of Enthalpy Change and Implicit Given of Initial Temperature of Calorimeter

I would like to ask two separate questions. But first, so that we are on the same page, the experiment used a constant-pressure calorimeter, and it is a neutralization reaction of 1M of HCl and 1M of ...
2k views

### Are food calorie values really integers?

According to what I've seen, fat has a listed caloric value of 9 Cal/g, while carbs and protein have listed caloric values of 4 Cal/g.* Are these numbers exact, or have they been rounded? And if they ...
1 vote
2k views

### Water evaporation from calorimeter giving less exothermic enthalpy value?

To find the enthalpy change of combustion for an alcohol, you use a calorimeter filled with water and heat it by burning an alcohol. I was told that usually experimental values for the enthalpy ...
8k views

### Confusion on when to use mass of entire solution when performing q=mc∆T

I am studying for the AP Chemistry exam in May 2020. While studying, I encountered a doubt. In Problem 1 (the question on the top), the educator saw that the problem was referring to the solution as a ...
36 views

### How does the heat capacity of a calorimeter interact with the specific heat capacity of the water inside it?

I saw this basic calorimetry question and it included the heat capacity of the calorimeter (1550 J/°C) but it also included that there were 150 g of water inside the calorimeter as well (4.184 J/(G°C)....
23 views

### Is there any effect on bonds formation and reactants due to a reaction in adiabatic calorimeter

Is there any effect on reactants and bond formation due to a reaction going on a adiabatic calorimeter.We know enthalpy of a reaction should be measured at constant temperature but in adiabatic ...
1 vote
338 views

### Methylhydrazine Calorimetry

Below is a chemistry practice problem. I am curious why the change in heat of the oxygen molecules doesn't affect the calculations. Methylhydrazine ($\ce{CH6N2}$) is commonly used as a liquid ...
311 views

### Why can't calorimetry be used to measure fast reactions?

As my previous post was a bit unclear and unspecific, I am reformulating it. First of all this is a question that I had while reading some concepts my book introduces, so this isn't a homework ...
1 vote
2k views

### Enthalpy of combustion of 1-butanol

1-butanol $\ce{C4H10O}$ So I have absolutely no idea how to find the enthalpy and I did some looking on the internet with no use since I don't understand. I came here hoping someone generous could ... 1k views

### Calorimetry: Temperature Increase due to stirring of reactants

I am not yet in university, but I hear a common first-year chemistry lab/practical is to do calorimetry taking into consideration the small (and usually negligible) rise in temperature due to the ...
1 vote
256 views

### How to describe the enthalpy of acid dissociation in aqueous solutions?

How to describe the enthalpy of acid dissociation in aqueous solutions? If we had a weak acid "PB" that dissociates to give a proton and a conjugate base. Classically it would be described like the ...
1k views

### Calculating ΔH from bomb calorimetry

Suppose we carry out a reaction in a bomb calorimeter whose starting temperature is $298.15\ \mathrm K$. Here we assume $\Delta V$ is close enough to zero that we consider the process to be at ...
649 views

### Extrapolating from a calorimetry lab to find a new delta T with different volumes and grams of substance

So, we just finished an AP chem lab where the question was basically: Given the results of the lab were that $\pu{5 grams}$ of $\ce{CaCl2}$ and $\pu{45ml}$ of water produced a $\pu{13.33 ^\circ C}$ ...
2k views

### Heat transfer problem

For this problem, I'm wondering if the thermos should be involved in the heat transfer because right we have an equation in calorimetry: $q_\text{warm} =-(q_\text{cold} + q_\text{cal})$ A 125 g ...
1 vote
14k views

### Why are calorimeters often made of materials with low specific heats?

When building calorimeters, a material with a low specific heat is often used (such as Styrofoam, aluminum, etc.). However, why would a material with a low specific heat be preferred? My thought ...
187 views

### In what approximations, if any, can we assume a constant temperature in a Bomb calorimeter?

In most, if not all, general chemistry books, you will find that in from constant volume calorimeters, $\Delta H = \Delta U + RT \Delta n_\mathrm{g}$, which is, of course derived from $H = U + PV$. ...
702 views

### Is a low specific heat capacity for the material of the calorimeter good or bad?

I wish to ask if a low specific heat capacity of the material of the calorimeter means that the calorimeter would be more exact as it takes less heat for the material to reach equilibrium. I thought ...
394 views

### Does specific heat capacity of the container have an effect on the exactitude of a calorimetre?

I'm doing a lab on what is the best material for a calorimetre. I chose glass, aluminum, styrofoam cup, paper/cardboard cup and a plastic cup. I've found that the cardboard cup was the best followed ...
1k views

### Bomb Calorimeter vs Cup Calorimeter

In the textbook,it is said that bomb calorimeter measures the constant volume heat ,while the cup calorimeter measure Constant pressure Heat.I was wondering, why cup calorimeter is considered constant ...