Which of the responses below are sources of weighing error? I Weighing a sample that is warmer than ambient temperature.
II Cooling a sample in a desiccator prior to weighing.
III Periodically calibrating the balance.
IV The temperature of the balance changing over time.
A)I and II
B)I and III
C)II and IV
D)II and III
E)I and IV

Question

Quizplus · Accepted Answer

I and IV are sources of weighing error. Weighing a sample that is warmer than ambient temperature can cause air currents that affect the balance's reading. The temperature of the balance changing over time can also affect its accuracy and precision. Cooling a sample in a desiccator (II) is a correct procedure to avoid moisture absorption before weighing, not a source of error. Periodically calibrating the balance (III) is a maintenance procedure to ensure accuracy, not a source of error.

Which of the Responses Below Are Sources of Weighing Error