krit.club logo

Introduction to Chemistry - Common Laboratory Apparatus

Grade 6ICSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

•

Chemistry is the branch of science that deals with the study of the composition, properties, and structure of matter, such as H2OH_2O (water) and NaClNaCl (common salt).

•

Laboratory apparatus are primarily made of 'Pyrex' or 'Borosil' glass because it is transparent, easy to clean, and resistant to high temperatures and chemicals.

•

The Test Tube is used for heating small amounts of chemicals and observing reactions. A specialized 'Boiling Tube' made of hard glass is used for extreme heating.

•

Beakers are used for mixing, stirring, and heating larger volumes of liquids. They usually have a 'spout' for easy pouring.

•

Flasks come in different shapes: The Conical Flask is ideal for mixing without spilling, while the Round-bottomed Flask is used for gas preparation and heating where uniform heat distribution is required.

•

A Measuring Cylinder is used to measure the volume of liquids accurately, typically graduated in milliliters (mLmL).

•

The Bunsen Burner is the primary source of heat in the lab, consisting of a burner tube, an air hole, and a gas inlet.

•

A Tripod Stand and Wire Gauze are used together to support glassware during heating. The wire gauze, often containing an asbestos center, ensures even distribution of the flame.

•

A Retort Stand is used to hold and clamp other apparatus like burettes or flasks in a fixed position.

📐Formulae

Density(D)=Mass(M)Volume(V)Density (D) = \frac{Mass (M)}{Volume (V)}

1 liter (L)=1000 milliliters (mL)1 \text{ liter } (L) = 1000 \text{ milliliters } (mL)

1 milliliter (mL)=1 cubic centimeter (cm3)1 \text{ milliliter } (mL) = 1 \text{ cubic centimeter } (cm^3)

💡Examples

Problem 1:

Which apparatus would a student use to measure exactly 25 mL25 \text{ } mL of a liquid, and how should they read the measurement?

Solution:

A Measuring Cylinder should be used.

Explanation:

To get an accurate reading, the cylinder must be placed on a flat surface and the student's eye must be level with the 'lower meniscus' (the bottom of the curved surface) of the liquid.

Problem 2:

Why is a wire gauze placed between the glass flask and the flame of a Bunsen burner?

Solution:

To prevent the glass from cracking due to 'thermal shock' or uneven heating.

Explanation:

The wire gauze spreads the heat from the flame evenly across the bottom of the flask, ensuring the glass does not break from a concentrated hot spothot \text{ } spot.

Problem 3:

If a sample of a liquid has a mass of 50 g50 \text{ } g and occupies a volume of 25 mL25 \text{ } mL in a measuring cylinder, calculate its density.

Solution:

D=50 g25 mL=2 g/mLD = \frac{50 \text{ } g}{25 \text{ } mL} = 2 \text{ } g/mL

Explanation:

Using the formula D=MVD = \frac{M}{V}, we divide the mass by the volume to find the density of the substance.