Question

1. drag and drop the words with the descriptions.

two aqueous compounds exchange ions to produce two new compounds
bubbles are formed to indicate this type of product has formed
the separation of an ionic compound into separate ions
a compound that does not dissolve in water
choices
dissociation
double replacement reaction
gas
precipitate

1. choose the best answer.

look at the products of this equation. what is formed that provides evidence of a chemical change?
$2\ce{na_{3}po_{4}}(aq) + 3\ce{cacl_{2}}(aq) \
ightarrow 6\ce{nacl}(aq) + \ce{ca_{3}(po_{4})_{2}} \downarrow$
precipitate
water
gas

Explanation:

Part 1: Drag and drop

• "two aqueous compounds exchange ions to produce two new compounds" matches "double replacement reaction" (definition of double replacement reaction).
• "bubbles are formed to indicate this type of product has formed" matches "gas" (bubbles are a sign of gas production).
• "the separation of an ionic compound into separate ions" matches "dissociation" (definition of dissociation).
• "a compound that does not dissolve in water" matches "precipitate" (precipitates are insoluble in water).

In the equation \( \ce{2Na_3PO_4(aq) + 3CaCl_2(aq) -> 6NaCl(aq) + Ca_3(PO_4)_2 \downarrow} \), the \( \downarrow \) symbol indicates a precipitate (a solid that forms from aqueous solutions). Water and gas are not products here, and the precipitate shows a chemical change (formation of a new insoluble substance).

Answer:

1. double replacement reaction - two aqueous compounds exchange ions to produce two new compounds
2. gas - bubbles are formed to indicate this type of product has formed
3. dissociation - the separation of an ionic compound into separate ions
4. precipitate - a compound that does not dissolve in water

Part 2: Multiple Choice