How many formula units of sodium carbonate are in 2.87 moles?

Formula units are another way of expressing "molecules". One mole is equivalent to .

Use dimensional analysis to solve this problem.

2.87 moles

Then, cross off the moles in the given number and the denominator, and your remaining unit is molecules of sodium carbonate.

Then, multiply and divide accordingly to the fraction.

2.87 * 6.022*10^23 = 1.72 * 10^24. Notice how the given problem has only 3 sig figs, so the answer should also have 3 sig figs

Your final answer would be 1.72 formula units of sodium carbonate.

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.