Enthalpy of Neutralization
Neutralization occurs when an acid and a base react in equal quantities to produce a salt. For example, sodium hydroxide and hydrochloric acid react in water as follows.
NaOH + HCl ↔ H2O + NaCl
Of course, in water, these materials have ionized, and the true nature of the reaction is more like the following.
Na+ + OH- + H+ + Cl- ↔ Na+ + Cl- + H2O
Because the sodium and chloride ions don't participate in this reaction, they are termed spectator ions. The net reaction follows.
OH- + H+ ↔ H2O
Calorimetry is the technique of measuring the heat evolved or absorbed during some process. Here, that process is the chemical reaction of acid-base reaction to form salts. In each case that you'll look at, the net reaction is the formation of water. You'll measure the enthalpy (heat) of each reaction and correlate the results to the chemicals being reacted.
The calorimeter being used resembles the diagram to the right. The t-shaped object on the left represents a thermometer. The pair of vertical lines represent electrical posts that allow a resistance wire to be heated and which is not used in this lab.
The neck's calibrations show 0.1 ml per large calibration mark and 10 microliters (μl) for the smaller marks. Microliters are 1,000 times smaller than milliliters.Some analog measurements are listed below.
Length: meter stick
Mass: triple-beam balance
Force: spring scale
Volume: graduated cylinder
In this lab, you'll measure distance, mass, temperature, force, and volume.
Any measurement consists of two parts:
the value and
If you report a length as being 1.7, no one will know whether it's the size of a bacterium or a continent. Don't leave out the units.
Accuracy tells how good your measuring device is.
Does it measure correctly?
Precision is all about repeating measurements and getting the same value.
Try to measure the height of someone who won't stand still.