Question

Which of the materials would she place in her plastic bag to make a heat pack? Choose two of the 4 answers.
A.
Calcium chloride and water
B.
Vinegar and baking soda
C.
Citric acid solutions and baking soda
D.
Laundry detergent and water
E.
Ammonia chloride and water

Answers

GPT-4o mini
To make a heat pack, you would typically want to choose materials that undergo an exothermic reaction, releasing heat when combined. Based on the options given:

A. **Calcium chloride and water** - When dissolved in water, calcium chloride releases heat, making it a good choice for a heat pack.

E. **Ammonium chloride and water** - When dissolved in water, ammonium chloride absorbs heat, resulting in a cooling effect rather than a warming one.

Based on this reasoning, the best choices are:

**A. Calcium chloride and water**
**C. Citric acid solutions and baking soda** (this combination can also produce heat, but the reaction and heat generation can vary based on concentration and other factors)

Thus, the primary choice for effective heat generation is:

**A. Calcium chloride and water**
**C. Citric acid solutions and baking soda**

If you need to choose only two that are most effective and common for a heat pack, stick with **A** and consider **E**, which also yields some heat but less effectively than **A**.