An iron ore sample was dissolved in hydrochloric acid and the iron was obtained as Fe2+(aq). The iron solution was titrated with 38.54 mL of 0.471 M Ce4+ solution according to the balanced chemical equation below.
Ce4+(aq) + Fe2+(aq) -> Ce3+(aq) + Fe3+(aq).
Calculate the mass of iron in the original ore sample. Please round your answer to the nearest hundredths place.
mol of Ce4+ = 38.54 mL x 0.471 M = 18.15 mmol
mol of Fe = mol of Fe2+ = mol of Ce4+ = 18.15 mmol
mass of iron = 18.15 x 55.84 = 1013.50 mg = 1.01g
Did I do this problem correctly. And did I round to the hundredths place appropriately?
it is correct.
Wow, you really ironed out the problem! Your calculations look on point, and you rounded the mass of iron to the nearest hundredths place perfectly. Great job! Now you can iron your clothes with confidence, knowing you've got the right amount of iron.
Your calculations seem to be correct, but the rounding is not accurate according to the instructions. You were instructed to round to the nearest hundredths place, but you rounded the mass of iron to the nearest tenth place.
To round to the nearest hundredths place, you need to consider the digit in the thousandths place. In this case, the digit in the thousandths place is '5', which means you need to round the mass of iron to the nearest even number in the hundredths place (since '5' is followed by '0'). Therefore, the correct rounded mass of iron would be 1.01 grams.
So, yes, you did solve the problem correctly, but the rounding is not accurate according to the instructions.
Yes, you did the problem correctly. To calculate the mass of iron in the original ore sample, you first determined the amount of Ce4+ used in the titration, which was 38.54 mL x 0.471 M = 18.15 mmol. Since the Ce4+ and Fe2+ react in a 1:1 ratio according to the balanced equation, the number of moles of Fe in the sample is also 18.15 mmol.
Then, you used the molar mass of iron (55.84 g/mol) to convert the moles of Fe to mass. Multiplying 18.15 mmol by 55.84 g/mol gives you 1013.50 mg.
Lastly, you rounded your final answer to the nearest hundredths place, which is 1.01 g. This is appropriate since the original question asked for the mass of iron to the nearest hundredths place.