Which of the following statements are true about BCA tables and ICE tables? (Choose all that apply)
A. An ICE table requires units of concentration while a BCA table requires units of moles.
B. ICE tables and BCA tables can be used interchangeably.
C. A balanced chemical equation is needed to use an ICE table and BCA table.
D. An ICE table requires units of moles while a BCA table requires units of concentration.
The correct answer and explanation is:
The correct answers are:
A. An ICE table requires units of concentration while a BCA table requires units of moles.
C. A balanced chemical equation is needed to use an ICE table and BCA table.
Explanation:
A. ICE Table vs. BCA Table Units:
- ICE Table (Initial, Change, Equilibrium): This table is commonly used for chemical equilibrium problems involving concentrations. In an ICE table, you typically use the units of concentration (moles per liter, M) for each species involved in the reaction. This is because it is often used to track the change in concentration of reactants and products at equilibrium.
- BCA Table (Before, Change, After): This is similar to an ICE table but tends to use units of moles (mol) instead of concentration. The BCA table is particularly useful when the number of moles of substances is important (e.g., during stoichiometric calculations). The initial amounts are given in moles, and changes in moles are calculated through the reaction.
So, the statement is true: an ICE table requires concentration units, while a BCA table requires moles.
B. Interchangeability of ICE and BCA Tables:
Although both ICE and BCA tables are used to describe changes in the quantities of reactants and products in a chemical reaction, they are not always interchangeable. The primary distinction is the units: ICE tables focus on concentrations (molarity), and BCA tables deal with moles. The conversion between them depends on the specific context of the problem. For instance, if the volume of the solution is changing or if concentration is needed, then the ICE table is more appropriate. So, ICE and BCA tables cannot always be used interchangeably.
C. Requirement of a Balanced Chemical Equation:
Both ICE and BCA tables require a balanced chemical equation. The stoichiometry of the balanced equation dictates the mole ratios between reactants and products. These ratios are essential for determining the changes in concentration or moles of the substances involved in the reaction. Without a balanced equation, the calculations would be inaccurate or impossible.
D. BCA Table Units:
This statement is false because a BCA table typically requires units of moles, not concentrations. The change in the number of moles of substances is tracked in a BCA table, which is useful for stoichiometric and mass balance calculations.
In summary, the correct choices are A and C, based on the nature and purpose of the tables.