## What is the unit for QRXN?

a. Use ∆T to compute qrxn (in kJ/gram) and ∆Hrxn (in kJ/mol)for each reaction.

**Is QRXN the same as Delta H?**

3. qrxn represents the amount of heat at constant pressure for the amounts that you used. To find ∆H for a reaction, it has to correspond to the number of moles of everything in the balanced equation.

### What is Q RXN?

-qrxn = qcal + qwater. This way we do not always have to add exactly. the same amount of water to the calorimeter. -qrxn = Ccal T + m s T. We can measure the mass of the water which is used, we can measure the temperature change, and we know the specific heat of water.

**Why Cannot calculate QRXN directly?**

The temperature change measured is that of the water. None of the other. The temperature change measured is not due to the reaction, rather it is due to the solution in the coffee cup trying to reach equilibrium with the room temperature.

## What does it mean if QRXN is negative?

The q value represents the heat of the reaction. When the temperature of the bomb increases, the ΔT is positive, and the q value must be negative as the bomb has heated due to energy being released by the reaction. The negative sign accomplishes the qrxn = -qsur that is used in coffee cup calorimetry.

**What does a negative QRXN mean?**

negative qrxn means. exothermic – solution is absorbing heat and warming up.

### How do you calculate QCAL in chemistry?

The heat gained by the calorimeter, q cal, is determined from the formula, qcal = Ccal×Δt, where Δt is the change in temperature undergone by the mixture.

**What are calorimeters used to measure?**

calorimeter, device for measuring the heat developed during a mechanical, electrical, or chemical reaction, and for calculating the heat capacity of materials.

## What is MC delta T used for?

Q=mcΔT Q = mc Δ T , where Q is the symbol for heat transfer, m is the mass of the substance, and ΔT is the change in temperature. The symbol c stands for specific heat and depends on the material and phase. The specific heat is the amount of heat necessary to change the temperature of 1.00 kg of mass by 1.00ºC.

**What is Ccal measured in?**

As a unit the whole calorimeter (water + hardware) will have a definite heat capacity, Ccal which will have units of J/˚C or kJ/K. Note that there is only energy per degree temperature for units for a plain heat capacity.