Which reaction had a negative T value: Citric Acid and baking soda or metal and hydrochloric Acid
I assume you are asking which substance decreased the temperature when dissolved in water? I also assume you did the experiment. Look at your notes. Or are you trying to dry lab the experiment?
To determine which reaction had a negative T (temperature) value, we need to consider the enthalpy change (∆H) associated with each reaction. The enthalpy change is a measure of the heat energy released or absorbed during a chemical reaction.
Let's break down the two reactions:
1. Citric Acid and Baking Soda:
The reaction between citric acid (C6H8O7) and baking soda (NaHCO3) is an acid-base reaction. It can be represented by the following balanced equation:
C6H8O7 + 3NaHCO3 -> 3CO2 + 3H2O + Na3C6H5O7
This reaction is exothermic, meaning it releases heat to the surroundings. When an exothermic reaction occurs, the enthalpy change (∆H) is negative.
2. Metal and Hydrochloric Acid:
The reaction between a metal and hydrochloric acid (HCl) is a redox reaction. The specific metal used will determine the reaction. For example, let's consider the reaction between zinc (Zn) and hydrochloric acid:
Zn + 2HCl -> ZnCl2 + H2
This reaction is also exothermic, so the enthalpy change (∆H) is negative.
Therefore, both the reaction between citric acid and baking soda and the reaction between a metal (like zinc) and hydrochloric acid have negative enthalpy changes (∆H). Hence, both reactions would have negative T (temperature) values since the release of heat during the reaction leads to a decrease in temperature.