Mixing solutions of iron(III) nitrate and sodium hydroxide precipitates the pigment iron(III) hydroxide. What mass of iron(III)
hydroxide is produced from 24.1 grams of sodium hydroxide?
Type the correct answer in the box. Express your answer to the correct number of significant figures C. Use the
periodic table to obtain the atomic masses of the elements.
The reaction will produce ___
grams of iron(III) hydroxide.

21.5

Explanation:The reactants are sodium hydroxide and iron(III) nitrate. From the periodic table, determine that the molar mass of NaOH is 39.997 grams/mole and the molar mass of Fe(OH)3 is 106.866 grams/mole.

This is a double displacement reaction that produces iron(III) hydroxide and sodium nitrate.

This is the balanced equation:

Fe(NO3)3 + 3NaOH → Fe(OH)3 + 3NaNO3.

The equation shows that for every three moles of NaOH, one mole of Fe(OH)3 is produced. So, there are three times as many moles of NaOH used up as there are moles of Fe(OH)3 produced.

Find the number of moles of NaCl and divide by 3 to get the moles of Fe(OH)3 produced:

24.1 g NaOH ×  = 0.603 mol NaOH

0.603 mol NaOH ×  = 0.201 mol Fe(OH)3

Multiply the number of moles of Fe(OH)3 by its molar mass to get the number of grams of Fe(OH)3 produced:

0.201 mol Fe(OH)3 × 106.866 g/mol Fe(OH)3 = 21.5 g Fe(OH)3

The answer is rounded to three significant figures.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.