Using Laboratory EquipmentUsing Laboratory EquipmentChapter 3Chapter 3

Laboratory EquipmentLaboratory Equipment

Containers and Holding Devices●Basic to lab work

Beakers – -a glass container that has a wide mouth and holds solids and liquids.

-use for approximate

amounts.

Graduated cylinder-

-tall, cylindrical container used for measuring the volume of liquids.

-use for exact measurements.

Meniscus – -the bottom of the curve a liquid forms in a container.

Test Tubes –-a cylindrical container that holds a small quantity of a solid or liquid.

Erlenmeyer flasks –a cone-shaped container with a narrow neck and a broad flat bottom.

Stirring rod◦ Used to mix

chemicals and liquids for laboratory purposes.

◦ Usually made of solid glass, about the thickness and slightly longer than a drinking straw, with rounded ends.

Burets--a long, thin cylinder, which is marked to 0.1 of a milliliter.-use to transfer exact amounts of liquids.

Thermometers – -Marked with the Celsius scale, handles much higher temperatures.

Balance – -a scientific instrument that determines the mass of material.

Mass is a measure of the amount of matter in a sample.

Finding the mass of a substance placed on a balance is known as “massing” it.

Mass is constant. An object will always have the same mass value.

To mass a substance- need a container to hold it

How do you find the mass of as substance but not its container?

What is the procedure called? (page 52)

Taring – 1. Mass the empty container.2. Subtract that value from the mass of

the substance and the container

together.3. Difference is the amount of mass.

Weighing applies to using a spring scale to measure weight.

Weight is the gravitational pull of the Earth on an object.

Calibrating Measuring Calibrating Measuring EquipmentEquipmentHow can you be sure the

measurements are accurate?To ensure correct readings,

instruments are calibrated.Calibrate –

-to check, adjust, or standardize the marks on a measuring instrument.

Explain which piece of laboratory equipment Explain which piece of laboratory equipment would be most useful for of the following tasks.would be most useful for of the following tasks.

1. Holding 50 mL of boiling water.

2. Measuring exactly 43 mL of water.

3. Weighing out 120 grams of sodium chloride.

4. Mixing two liquids together.