This document provides guidance on writing an eighth grade science lab report on how temperature affects the rate of a chemical reaction. It recommends writing a focused research question that specifies the independent variable (temperature from 40 to 80 degrees Celsius) and dependent variable (mass of reaction mixture in grams). The hypothesis should state that as temperature increases, the mass will decrease due to one of the products escaping as a gas. The method section describes the controlled variables and step-by-step process for conducting trials at different temperatures, recording data, and presenting it in a table.

1. How to write a coherent eighth grade ‘design’ lab report

2. 1. Write a descriptive research question.Specify the independent and the dependent variables, along with their units.

3. Example: Investigating a factor that affects the rate of a reaction. (Broad)To investigate the effect of increasing the temperature, from 40oC to 80oC, on the mass of the reaction mixture (gram) containing calcium carbonate and dilute hydrochloric acid. (Focused)

4. 2. Write a detailed hypothesis.

5. As the temperature was increased, the mass will decrease.As the temperature of the reaction mixture increases from 40oC to 80oC, the mass change will decrease by because one of the products, being a gas, escapes the reaction container leading to a loss in mass.

6. 3. Describing variablesIndependent: Temperature Dependent: MassControlled: acid used, same calcium carbonate

9. Materials:Hydrochloric acid, limestone, flask, electrical scale, and timer.

10. Materials:Calcium carbonate pellets (50 g)1 mol dm-3 hydrochloric acid(125 cm3)Conical flask (250 cm3)Graduated cylinder (100 cm3)Hot plateDropperElectronic balance Safety goggles

11. Method: 1. Gather all materials.2. Add acid to the calcium carbonate in the flask and place it on the balance.3. Note the mass change.

12. Method:1. Measure 10 g of calcium carbonate on an electronic balance, and transfer it into a 250 cm3 conical flask.2. Using a graduated cylinder, measure 25 cm3 of dilute hydrochloric acid into an empty flask.3. Heat the acid up to 40oC on a hot plate.4. Add the heated acid to the calcium carbonate pellets in the flask.

13. 5. Place the flask on an electronic balance and note its initial mass and also after every ten seconds.6. Repeat steps 1 to 5 four more times.7. Also, repeat steps 1 to 6, five times each, with acid at 50oC, 60oC, 70oC, and 80oC.8. Record both qualitative and quantitative data in an appropriate table.

14. I hope this PowerPoint presentation helped you to understand the mechanics of writing a ‘design’ lab report.