How many grams of magnesium oxide form when \(14.8 \mathrm{~L}\) of oxygen gas, measured at STP, completely reacts with magnesium metal according to this reaction? $$ 2 \mathrm{Mg}(s)+\mathrm{O}_{2}(g) \longrightarrow 2 \mathrm{Mg} \mathrm{O}(s) $$

Understanding Standard Temperature and Pressure (STP) is crucial when dealing with gases in stoichiometry problems. STP is defined as a temperature of 0°C (273.15 K) and a pressure of 1 atmosphere (atm). This standard is important because it provides a reference point where the volume of any gas can be related to the number of moles present. At STP, one mole of any ideal gas occupies 22.4 liters of volume.

This concept allows us to perform gas volume to moles conversion simply by using the relation that 22.4 L of any gas at STP equals one mole. When working with gases, it is always important to check whether the conditions given are at STP, as this affects the volume that a given number of moles of the gas will occupy.

Molar mass is a fundamental concept in chemical reaction stoichiometry and is defined as the mass of one mole of a substance. It is usually expressed in grams per mole (g/mol). Calculating molar mass involves summing up the atomic masses of all atoms in a molecule as provided by the periodic table. For instance, for magnesium oxide (MgO), the molar mass is calculated by adding the atomic mass of magnesium (Mg, approximately 24.31 g/mol) to that of oxygen (O, approximately 16.00 g/mol), which gives us 40.31 g/mol for MgO.

To convert moles of any substance to grams - a necessary step in stoichiometry - you multiply the number of moles by the molar mass. It's essential to calculate molar mass accurately as it is used to convert between mass and moles, a key step in solving stoichiometry problems.

Chemical reaction stoichiometry involves the quantitative relationship between reactants and products in a chemical reaction. These relationships are governed by the balanced chemical equation. The coefficients in front of chemical formulas represent the molar ratios in which reactants combine and products form. For example, in the reaction \(2 \text{Mg} + \text{O}_2 \rightarrow 2 \text{MgO}\), the coefficients indicate that 2 moles of magnesium (Mg) react with 1 mole of oxygen gas (\(\text{O}_2\)) to produce 2 moles of magnesium oxide (MgO).

Understanding these ratios is crucial for predicting how much product will form from a given amount of reactants and vice versa. This is why stoichiometry is often referred to as 'the mathematics of chemistry', as it allows chemists to calculate the exact amounts of substances required or produced in a reaction.

Gas volume to moles conversion is a common operation in stoichiometry, particularly when dealing with reactions that involve gaseous reactants or products at STP. The process is straightforward due to the molar volume of a gas at STP, which is always 22.4 L/mol. This means that given a volume of gas at STP, the number of moles can be found by dividing the volume by 22.4 L/mol.

In the exercise given, the volume of oxygen gas is 14.8 liters. To find the amount in moles, it's simply a matter of performing the division: \( \text{number of moles} = \frac{\text{volume of gas (L)}}{22.4 \text{ L/mol}} \), which will yield the moles of oxygen used in the reaction. This conversion is a key step in solving many gas-related stoichiometry problems and is integral to the manipulation of chemical equations.