Final answer:
To speed up the chemical reaction between vinegar and baking soda without altering the results, Monica and Alexis should increase the temperature, such as by using a hot plate, which enhances the frequency and energy of particle collisions and therefore increases the reaction rate.
Step-by-step explanation:
Speeding Up Chemical Reactions
When Monica and Alexis are conducting their experiment with baking soda and vinegar, there are various ways they can affect the rate of the reaction. Given the multiple-choice options, the correct answer to speed up the reaction without affecting the results would be to increase the temperature of the reactants. Option d, which suggests performing the experiment on a hot plate, will indeed increase the temperature, leading to a faster reaction rate. This happens because higher temperatures provide reactant particles with more energy, resulting in an increased frequency and force of collisions, thereby increasing the likelihood of overcoming the activation energy barrier and forming products faster.
On the contrary, adding more baking soda might change the proportion of reactants and could potentially alter the results of the experiment. Adding ice to decrease the vinegar's temperature would slow down the reaction, not speed it up. Therefore, these options are not suitable for the purpose of speeding up the reaction without changing the experimental outcomes.