Mass Measurement and Significant Figures

The video tutorial explains how to calibrate a balance and measure the mass of a sample accurately. It provides a step-by-step guide on using a balance, including moving the 100, 10, and 1 gram riders to align the pointer with the zero mark. The total mass is calculated by summing the values from the three beams. The tutorial also covers the concept of reading error, which can lead to different recorded masses, and explains significant figures, highlighting the certainty and uncertainty in measurements.

What is the first step after calibrating the balance to measure the mass of a sample?

• Place the sample on the pan

• Move the 100 gram rider to the right

• Adjust the pointer to zero

• Read the mass directly from the balance

How do you adjust the 100 gram rider when measuring mass?

• Move it to the right until the pointer is below zero

• Move it to the right until the pointer is above zero

• Move it to the left until the pointer is below zero

• Move it to the left until the pointer is above zero

What is the total mass if the readings are 100 grams, 70 grams, and 5.42 grams?

• 180.42 grams

• 175.42 grams

• 170.42 grams

• 175.24 grams

To what precision can the mass be recorded on this balance?

• To the nearest tenth of a gram

• To the nearest hundredth of a gram

• To the nearest gram

• To the nearest thousandth of a gram

What is the term for when two people read the same mass but record different values?

• Measurement error

• Reading error

• Calibration error

• Significant error

What is the reading error in this mass measurement process?

• Plus or minus one thousandth of a gram

• Plus or minus one hundredth of a gram

• Plus or minus one tenth of a gram

• Plus or minus one gram

How many significant figures are in the measurement 175.42 grams?

• Six

• Four

• Five

• Three

Which digit in the measurement 175.42 grams is considered uncertain?

• 2

• 4

• 7

• 1