Question

Determine the amount of bromine (in milligrams) in $500$ mL of solution of $0.1$ $M$ $NaBr$.

• A. $200mg$
• B. $400mg$
• C. $2,000mg$
• D. $4,000mg$
• E. $20,000mg$

Answer 1

The correct option is D $4,000mg$

The number of moles of $NaBr$ in 500 mL of 0.1 M solution $=0.1mol/L\times \frac{500mL}{1000mL/L}=0.05mole$.
The number of moles of bromide ions $=$ Number of moles of bromine $=$ 0.05 mol
The atomic mass of bromine is 79.9 g/mol.
The mass of bromine $=79.9g/mol\times 0.05mol=4g=4,000mg$