What mass (in g) does 7.98 moles of Kr hare?
The correct answer and explanation is:
To find the mass (in grams) of 7.98 moles of krypton (Kr), we use the formula: Mass=Moles×Molar Mass\text{Mass} = \text{Moles} \times \text{Molar Mass}
Step 1: Find the molar mass of krypton (Kr)
From the periodic table, the atomic mass of krypton is: Molar Mass of Kr=83.80 g/mol\text{Molar Mass of Kr} = 83.80 \, \text{g/mol}
Step 2: Multiply moles by molar mass
Mass=7.98 mol×83.80 g/mol\text{Mass} = 7.98 \, \text{mol} \times 83.80 \, \text{g/mol} Mass=668.82 g\text{Mass} = 668.82 \, \text{g}
✅ Final Answer:
668.82 g\boxed{668.82 \, \text{g}}
🔍 300-Word Explanation:
In chemistry, the mole is a standard scientific unit for measuring large quantities of very small entities like atoms or molecules. The molar mass tells us how much one mole of an element or compound weighs in grams. For elements, this value is numerically equal to the atomic mass listed on the periodic table.
Krypton (Kr) is a noble gas with an atomic number of 36. Its atomic mass is approximately 83.80 amu (atomic mass units), and this is also its molar mass, meaning one mole of krypton atoms weighs 83.80 grams.
To determine how much 7.98 moles of krypton weigh, we multiply the number of moles by the molar mass. This operation gives us the total mass of krypton in grams. Mass=Moles×Molar Mass=7.98×83.80=668.82 g\text{Mass} = \text{Moles} \times \text{Molar Mass} = 7.98 \times 83.80 = 668.82 \, \text{g}
This calculation is fundamental in chemistry, especially when preparing gases or calculating reactants and products in a chemical reaction.
Understanding mole-mass conversions helps in quantifying substances accurately, which is essential for laboratory experiments, industrial chemical production, and even environmental calculations involving gases in the atmosphere.
Thus, 7.98 moles of krypton weighs 668.82 grams.