Question

How would your calculations for the mass of Mg metal present in the sample have been affected (if at all) by the fallowing observations? Clearly explain your reasoning fo reach answer. 1. Your instructor had inverted two numbers when reading the pressure and reported wha the barometric pressure was 754 torr when in fact the correct room pressure was 745 torr. 2.Your partner had tightly held the gas-filled porition of the buret in his hand while you were trying to determine the difference in the water levels. 3. An edge of the Mg ribbon was outside the buret and some hydrogen may have escaped 4 You did not correct for the difference in water levels 5.You added rather than subtracted the vapor pressure of water to your final pressure reading

Answer 1

Solution :=

1. Your instructor had inverted two numbers when reading the pressure and reported wha the barometric pressure was 754 torr when in fact the correct room pressure was 745 torr.

Solution :- the room pressure 754 torr is incorrect therefore the pressure of the H2 gas would be less therefore it will give less moles of H2 which leads to less moles of Mg and hence less percent of the Mg

2.Your partner had tightly held the gas-filled porition of the buret in his hand while you were trying to determine the difference in the water levels.

Solution :- When the gas filled burrete is held tightly then it will increase the water level so it will lead to less volume of the H2 which will give less percent of the Mg.

3. An edge of the Mg ribbon was outside the buret and some hydrogen may have escaped

Solution :- When some of hydrogen is escaped then it gives less moles of H2 produced by the reaction this means less Mg is reacred so it will lead to the less percent of the Mg.

4 You did not correct for the difference in water levels

Solution :- If the difference in the water level is not corrected then higher volume lead more moles of H2 which leads to the higher Mg reacted therefore it will give higher percent of the Mg

5.You added rather than subtracted the vapor pressure of water to your final pressure reading.

Solution :- When the pressure is added then pressure of the H2 gas would be higher than actual therefore it will give more moles of H2 which gives the higher percnt of the Mg in the sample.