Under what circumstances might be important to know the activity tendencies of elements?
1 answer:
Answer: It is very important to know the activity tendencies of the elements. The activity tendencies tells us about whether the element is reactive or not.
In the redox-reaction where there is a need to know the oxidizing agent and reducing agent, we can know it easily from the activity tendencies. The elements lying above the reactivity series are better reducing agents.
In the substitution reactions, the activity tendencies helps us to know which element will replace the other. The element lying above in the series will replace the element lying below it.
where, N is an element that lies above in the reactivity series
M is an element that lies below in the reactivity series
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0.85 moles formula units of lead nitrate will produce 0.57 moles formula units of chromium (III) nitrate.
<h3>Explanation</h3>Typically, the oxidation state of Pb in lead nitrate tend to be +2. In other words, Pb in lead nitrate tends to exist as ions. The formula for a nitrate ion is
. The charge on each of the nitrate ion is -1. The charge on the two ions should balance. As a result, each
ion in lead nitrate would pair up with two
ions. The formula for lead nitrate will be
. Each formula unit of lead nitrate will contain one
ion and two
ions.
The "III" in the name "chromium (III) nitrate" is a Roman Numeral. It indicates that the oxidation state of Cr in chromium (III) nitrate is +3. The Cr in that compound will exist as . Similarly, each
will pair up with three
ions. The formula for chromium (III) nitrate will be
. Each formula unit of chromium (III) nitrate will contain one
ion and three
ions.
0.85 moles formula units of lead nitrate will contain 0.85 × 2 = 1.7 moles of ions. Those nitrate ions will end up in 1.7 / 3 = 0.57 moles formula units of chromium (III) nitrate. As a result, the reaction will produce 0.57 moles formula units of chromium (III) nitrate.