a. If the liquid level in the eudiometer tube is lower than that in the beaker, and this is not taken into consideration, the volume of gas collected in the eudiometer tube will be lower than it should be. The calculated value of R, which is obtained using the collected gas volume, will be smaller than the actual value. This is because the gas volume is inversely proportional to the calculated value of R. If the gas volume is underestimated, the calculated R value will be overestimated.
b. If the balance used to weigh the magnesium gives a mass that is higher than the actual mass, the number of moles of magnesium will be overestimated. This will lead to an overestimation of moles of hydrogen gas too, since the reaction between magnesium and an acid produces hydrogen gas. Since the calculated R value is directly proportional to the number of moles of gas, an overestimate of moles of gas will result in an overestimate of the calculated R value.
c. If some H2 gas escapes into the beaker during the reaction, the amount of gas collected in the eudiometer tube will be lower than it should be. This will result in an underestimate of the gas volume. As mentioned in (a), if the gas volume is underestimated, the calculated R value will be overestimated. This is because the gas volume is inversely proportional to the calculated value of R.
What would be the effect on the calculated value of R of each of the following experimental errors?
Explain each answer.
a. the liquid level in the eudiometer tube is lower than that in the beaker, but this is not taken into consideration in the calculations.
b. the balance used to weight the magnesium gives a mss that is higher than actual
c. some H2 escapes into the beaker during the reaction.
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