Question

Giovanni created this chart to study for an exam.

Compound I uses
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Sodium Hydroxide (NaOH) Plastic, soap, and paper production
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Iron oxide (FeO) Toothpastes and antacids
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Calcium chloride (caCl2) Snow removal
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Calcium carbonate (CaCO3) Dark pigment in makeup

Which best describes how to correct the error in the chart?

A) Remove “plastics” from the uses for sodium hydroxide.
B) Swap the uses for iron oxide and calcium carbonate.
C) Change the use for calcium chloride to “used in preservatives.”
D) Add “de-ice roads” to uses for calcium carbonate.

Answer 1

Calcium carbonate is indeed used as an antacid (among Mg(OH)2, Al2(OH)3 and NaHCO3).

Ferrous oxide or Iron (II) oxide is a dark substance, and I would certainly think twice before using a dark tooth paste (Yew! ) It might even rust if left in the mouth for some time!

Answer 2

Answer;

B) Swap the uses for iron oxide and calcium carbonate.

Explanation;

• Calcium carbonate is a compound that is naturally found in marble, chalk and limestone. It is used in pharmaceutical applications as a cost effective dietary calcium supplement, and also used in antacids.
• Calcium carbonate is also found in products such as baking powder, tooth paste, and wine among others.
• Iron oxides are compounds of iron that are used as coloring agents in some cosmetics. The forms of iron oxides used in cosmetics are normally synthetic.