2 Draw a line graph to illustrate your results. What will be on the x-axis and what will be on the y-axis? Give your graph a heading. 7 Conclusion: Do you accept or reject your hypothesis? Motivate your answer using your experimental results.

The independent variable is the quantity that is changed by the experimenter. In this experiment, it is the amount of white vinegar added (if observing the pH change of bicarbonate solution).

$$\text{x-axis: } \boxed{\text{Number of teaspoons of white vinegar added}}$$

The dependent variable is the quantity that is measured and changes in response to the independent variable. In this experiment, it is the pH of the solution.

$$\text{y-axis: } \boxed{\text{pH of the test solution}}$$

The heading should clearly describe what the graph illustrates.

$$\text{Graph Heading: } \boxed{\text{Effect of White Vinegar on the pH of Bicarbonate of Soda Solution}}$$

7. Conclusion: Do you accept or reject your hypothesis? Motivate your answer using your experimental results.

A typical hypothesis would be that adding an acid to a base will decrease the pH.

• Hypothesis: Adding an acid (white vinegar) to a base (bicarbonate of soda) will decrease the pH of the solution.

Based on the hypothetical results where the pH decreased from 9 to 4 as vinegar was added, the hypothesis is supported.

• Accept the hypothesis.

The motivation should directly reference the observed changes in pH.

• Motivation: When white vinegar (an acid) was added to the bicarbonate of soda solution (a base), the pH of the solution decreased from an initial value of 9 (basic) to 6 (slightly acidic) after 1 teaspoon, and further to 4 (acidic) after 2 teaspoons. This observed decrease in pH demonstrates the neutralization of the base by the acid, which supports the hypothesis.