What is the mass in grams of 1.2 moles of K?
What is the mass in grams of 1.2 moles of K?
The Correct Answer and Explanation is:
To find the mass in grams of 1.2 moles of potassium (K), use the formula: Mass=Moles×Molar Mass\text{Mass} = \text{Moles} \times \text{Molar Mass}Mass=Moles×Molar Mass
The molar mass of potassium (K) is approximately 39.10 g/mol. Mass=1.2 mol×39.10 g/mol=46.92 grams\text{Mass} = 1.2 \, \text{mol} \times 39.10 \, \text{g/mol} = \boxed{46.92 \, \text{grams}}Mass=1.2mol×39.10g/mol=46.92grams
Detailed Explanation
In chemistry, calculating the mass of a substance given its amount in moles is a basic yet essential skill. This process relies on the concept of molar mass, which is the mass of one mole of a given substance. Molar mass is expressed in units of grams per mole (g/mol), and its value corresponds to the atomic or molecular weight listed on the periodic table.
In this case, the element in question is potassium (symbol K), a soft, silvery metal that belongs to Group 1 of the periodic table, also known as the alkali metals. Potassium has an atomic number of 19 and an atomic mass of approximately 39.10 g/mol.
The question asks for the mass of 1.2 moles of potassium. A mole is a quantity that represents 6.022×10236.022 \times 10^{23}6.022×1023 atoms or molecules—Avogadro’s number. While this number is quite large, the mole allows chemists to work with atoms and molecules on a scale that is measurable in the lab.
To find the total mass of 1.2 moles of potassium, we multiply the number of moles by potassium’s molar mass: 1.2 mol×39.10 g/mol=46.92 g1.2 \, \text{mol} \times 39.10 \, \text{g/mol} = 46.92 \, \text{g}1.2mol×39.10g/mol=46.92g
Thus, 1.2 moles of potassium weigh 46.92 grams.
This calculation is crucial in stoichiometry, which involves measuring the reactants and products in chemical reactions. Knowing how to convert between moles and grams enables chemists to predict how much of a substance is needed or produced, ensuring accuracy in laboratory and industrial processes.
