Lab Error Flashcards (Magnesium and Titration)

Causes a artificially higher volume of gas in the burette, higher moles H2

Air in burette

Causes a artificially higher water level, so a lower gas volume and lower moles H2

Bubbles in water (stuck under water)

Increased temperature, as it is in the denominator, will lower moles of H2

Higher Water Temp

If there is higher water pressure, there must be less partial H2 gas pressure. Less H2 gas pressure, being in the numerator, means less moles H2

Higher Water Pressure

Less mass of Mg in grams will result in less moles of Mg, and since moles expected is the denominator of percent yield the percent yield will increase

Incorrect Measure of Mg

Bro if you forget vapor pressure its only H2 gas pressure, which increases if there is no vapor pressure and results in higher moles of H2

Vapor pressure not accounted

If you don’t swirl the flash, you’re gonna see pink in one spot and end early. Less volume NaOH, and therefore less concentration of [HCl]

Did not swirl flask

If you don’t prime your burette in the big 26, you are going to have less volume of NaOH than you’re supposed to. This will cause you to use more volume of NaOH, and more concentration of [HCl]. Artificially, that is.

Unprimed burette

If you have less volume of HCL in ur pipette bc ur lost and don’t know how to prime it, you will have less HCL in ur flask. This will cause artificially lower NaOH to be used to get the reaction to happen, and less HCL concentration.

Unprimed pipette

Air in burette will result in less NaOH being dispensed, so artificially higher NaOH and higher [HCl]

Air in burette

Air in the pipette will cause less HCL to be dispensed, so less NaOH and less [HCl]

Air in pipette

You are using too much NaOH, so also higher [HCl]

Over titration

Higher pressure inside, gas’s is more compressed so less volume is measured and therefore less moles of H2.

Water Level Too Low

Gas pressure is lower than atmosphere, gas therefore expands and artificially increased volume read, leading to higher moles of H2

Water Level Too High