How many grams are in 11.9 moles of chromium
The Correct Answer and Explanation is:
To find the mass of chromium in grams given the number of moles, we can use the molar mass of chromium and the formula:
[
\text{mass} = \text{moles} \times \text{molar mass}
]
- Find the molar mass of chromium (Cr):
The molar mass of chromium is approximately ( 51.9961 \ \text{g/mol} ). - Set up the calculation:
Given 11.9 moles of chromium, we plug in the values:
[
\text{mass} = 11.9 \ \text{moles} \times 51.9961 \ \text{g/mol}
] - Calculate the mass:
[
\text{mass} = 619.75259 \ \text{grams}
]
Rounded to three significant figures, the answer is approximately:
[
\text{mass} = 620 \ \text{grams}
]
Explanation:
The calculation above uses the concept of molar mass, which is the mass of one mole of a substance. Molar mass, expressed in grams per mole (g/mol), tells us how much 1 mole of an element weighs. In this case, chromium has a molar mass of 51.9961 g/mol, meaning 1 mole of chromium weighs about 52 grams. The formula to calculate mass from moles, ( \text{mass} = \text{moles} \times \text{molar mass} ), allows us to convert moles into grams, given that we know how many moles we have and the molar mass of the element.
This process is a fundamental part of stoichiometry, a branch of chemistry that involves calculations with chemical quantities and conversions. Understanding how to convert moles to grams (or vice versa) is essential in chemistry, as it allows scientists to weigh out specific amounts of substances for reactions and to predict the quantities of products formed.
In this case, by multiplying 11.9 moles of chromium by the molar mass, we determine that the total mass of chromium is approximately 620 grams. This approach to converting moles to grams can be applied to any substance as long as its molar mass is known.