Help me study for my Chemistry class. I’m stuck and don’t understand.


This week, you will be tasked with investigating the solubility of several chemical compounds

Chemists routinely measure the heat involved in a chemical change either experimentally or from enthalpy changes observed in other related reactions. In order to do the latter, the application of Hess’s law is required:

If a process can be written as the sum of several stepwise processes, the enthalpy change of the total process equals the sum of the enthalpy changes of the various steps.

In this experiment, you will determine and compare the quantity of heat energy released in three exothermic chemical reactions through application of Hess’s law.

Reaction 1: NaOH(s) → Na+(aq) + OH(aq) + x1 kJ

Reaction 2: NaOH(s) + HCl(aq) → H2O(l) + Na+(aq) + OH(aq) + x2 kJ

Reaction 3: NaOH(aq) + HCl(aq) → H2O(l) + Na+(aq) + OH(aq) + x3 kJ

In order to accurately measure the heat released in each reaction, we will be using a calorimeter. As discussed in the textbook, a calorimeter is a device used to measure the amount of heat involved in a chemical or physical process; the calorimeter used in this experiment will be a Styrofoam cup.

In the reactions above, the variables x1, x2, and x3 are the heats that are evolved during the reactions. The change in temperature that occurs for each reaction will be used to calculate the energy released in kJ/mol of NaOH used. We will assume for our calculations that any heat transferred to the Styrofoam cup and surrounding air will be negligible; we will also assume that the specific heat of water is 4.184 J/g∙°C. Thus, the applicable equation is simply

There are several objectives of this lab:

Before you start this laboratory assignment, you are encouraged to review Section 5.2 (p. 238) and Section 5.3 (p. 251) in the textbook. Throughout this laboratory assignment, you will be required to perform and thoroughly document your data and calculations. Be sure to record all observations and any relevant notes that you think you will need to include in your laboratory report; refer to the end of this document for information that must be included in your final report.


Preparing the Lab I

Performing the Reactions I

Performing the Reactions II

Performing the Reactions III

Data Analysis


This section should include notes about any observations or data collected during the lab.

Begin typing here.


This section will include all data collected during the lab.

Thermochemical Data

Tinitial (°C)

Tfinal (°C)

ΔT (°C)

moles NaOH

qreaction (kJ)


Reaction 1

Reaction 2

Reaction 3

*Note: You can copy and paste your data table into your report later.

Insert the net ionic equations here:

Reaction 1:

Reaction 2:

Reaction 3:

Report Requirements

This section contains key information that must be included in your typed report.

Note: All reports will be graded using the rubric embedded within the course.

Here are some questions to consider as you write your report: