CHEM 1030Measurement and Significant figures lab

CHEM 1030Measurement and Significant figures lab Measurement and Significant figures Lab Objectives:

1. Identify metric units used in measurement such as gram, meter, centimeter, millimeter, and milliliter. 2. Correctly use lab equipment.

3. State the correct number of significant figures in a measurement. Background: Scientists and allied health workers carry out laboratory procedures, take measurements and report results accurately and clearly. How well they do things can mean life or death to a patient. The system of measurement used in scientific research, hospitals and clinics is the metric system. The metric system is a decimal system based on units of 10. The metric system has one standard unit for each type of measurement. For example, the standard unit for measuring length is the meter. The table below shows the standard units of measurement. | Measurement | Metric unit | Symbol | length | meter | m | mass | gram | g | volume | liter | l | temperature | Degrees Celsius | C | time | seconds | s

Prelab questions:

1. What are the standard units of length, mass, volume and temperature in the metric (SI) system?

2. Why the metric (SI) system is is called a decimal system of measurement? What is the purpose of using prefixes in the metric (SI) system? T

3. Complete the table below by giving the name or the abbreviation for each metric unit listed and state the property it measures.

4. Describe each of the following as a measured number or an exact number. 5. How do you determine the last digit in any measured number? 6. If several different students measured the same length with a ruler would they get exactly the same result? Explain.

Procedure: A. Measuring length. The standard unit of length in the metric system is the meter (m). Prefixes can be used to indicate a length greater than or lesser than a meter. For example kilo(k), indicates a measurement 1000 times larger than a meter and centi(c) indicates a unit 100 times smaller than a meter.

1. What units are represented by the numbers on your ruler?

2. What do the small lines marked on the ruler represent? Millimeters Measure the following items: | item | Length | Estimated digit | Number of sig figs | Width of fingernail | 1.3 cm pinky | .3 | 2 | Length of your shoe | 35 cm | .3 | 2 | Height of book | 28.6 cm | .1 | 2 | Diameter of measuring cup (in lab kit) | 5.9cm | .6 | 2 3. Why could the measured values obtained by other students be different from yours?

4. Graduated cylinders can have numerous scales. Determine the value for the minor markings on each of the cylinders below (what unit does each line represent? .1, 2, 5, etc).

5. When an object is submerged in water it displaces its own volume of water causing the water level to rise. Using your beaker from your kit(or a measuring cup marked with ml, fill the beaker to a measure amount (be sure to leave enough space for the water to rise). Measuring mass. 6. State the number of significant figures in each of the following measurements. 11. Indicate the estimated digit in each of the following measurements.