Question

Reviewing main ideas 1. what is stoichiometry? 2. for each equation, write all possible mole ratios. ​
a. 2hgo(s) → 2hg(l) + o2(g)
b. 4nh3(g) + 6no(g) → 5n2(g) + 6h2o(l) ​3. how is a mole ratio used in stoichiometry? ​​ critical thinking 4. relating ideas what step must be performed before any stoichiometry problem is solved? explain.​

Answer 1

Hello!

1) Stoichiometry comes from the Greek stoikheion "Element" and métrón "Measure". It is the calculation of the quantitative relationships between reagents an products in a chemical reaction. The foundation of stoichiometry is the Law of Conservation of Mass. The relation between reagents and products can be estimated from the atomic theory and were first enunciated by Jeremias Benjamin Ritcher.

2) A. Mole Ratios are the relation between two elements or compounds in a chemical reaction and arise from the coefficients in a balanced chemical equation. For the reaction

2HgO(s) → 2Hg(l) + O₂(g)

The possible mole ratios are:

$\frac{2 moles HgO }{2 moles Hg}\\ \\ \frac{2 moles HgO}{1 mol O_2} \\ \\ \frac{2 moles Hg}{1 mol O_2}$

2) B. Mole Ratios are the relation between two elements or compounds in a chemical reaction and arise from the coefficients in a balanced chemical equation. For the reaction:

4NH₃(g) + 6NO(g) → 5N₂(g) + 6H₂O(l)

The possible mole ratios are:

$\frac{4 moles NH_3}{6 moles NO} \\ \\ \frac{4 moles NH_3}{5 moles N_2} \\ \\ \frac{4 moles NH_3}{6 moles H_2O}$
$\frac{6 moles NO}{5 moles N_2} \\ \\ \frac{6 moles NO}{6 moles H_2O} \\ \\ \frac{5 moles N_2}{6 moles H_2O}$

3) In stoichiometry, the mole ratio is crucial for the calculations because it is the quantity that allows us to convert the moles of an element or compound into the moles of another element or compound. Once we know the moles of a substance in the chemical reaction using the molar mass, if we want to know the moles of another substance we need to use the mole ratios.

4) Before solving any stoichiometry problem we need to balance the chemical equation for the given reaction. Balancing a chemical equation allows us to be sure that the Law of Conservation of Mass is fulfilled, and that any calculation or conclusion derived from the reaction is truthful. If the balancing is wrong, all mole ratios and calculations will be wrong too, as everything depends on the proper balancing of the chemical equation.

Have a nice day!