Final answer:
To find the number of moles in 276.9 g of CuBr, calculate its molar mass (143.454 g/mol) by adding the molar masses of copper and bromine. Then divide the mass of CuBr by its molar mass to get 1.93 moles of CuBr.
Step-by-step explanation:
To determine the number of moles in 276.9 g of CuBr, we first need to calculate the molar mass of the compound. Copper bromide (CuBr) has a molar mass of 63.55 g/mol for copper (Cu) and 79.904 g/mol for bromine (Br). Adding these values gives us the molar mass of CuBr, which is 143.454 g/mol (63.55 + 79.904 = 143.454 g/mol). Next, we use the molar mass to convert the mass of CuBr into moles using the formula:
Number of moles = Mass of substance (g) / Molar mass (g/mol)
By plugging in the values, we get:
Number of moles = 276.9 g / 143.454 g/mol = 1.93 moles
Therefore, there are approximately 1.93 moles of CuBr in 276.9 g of the compound.