Chemistry labs are designed for discovery, but they also contain heat sources, glassware, sharp tools, and chemicals that can burn, poison, ignite, or react unexpectedly. Lab safety matters because small choices, such as wearing goggles or reading a label, prevent injuries and protect everyone in the room. Hazard symbols give quick visual warnings so students can recognize risks before handling a substance.
A safe lab begins with preparation, attention, and respect for procedures.
Key Facts
- Always wear PPE: goggles, lab coat or apron, closed-toe shoes, and gloves matched to the chemical hazard.
- GHS pictograms identify major hazards such as flammable, corrosive, toxic, oxidizer, explosive, gas under pressure, health hazard, irritant, and environmental hazard.
- Dilution calculation: C1V1 = C2V2, where C is concentration and V is volume.
- Always add acid to water, not water to acid, because dilution releases heat that can cause splashing.
- pH = -log[H+], so lower pH means higher hydrogen ion concentration and usually greater acidity.
- In a spill: alert others, notify the teacher, isolate the area, use the correct spill kit, and dispose of cleanup materials as instructed.
Vocabulary
- PPE
- Personal protective equipment is gear such as goggles, gloves, and lab coats that reduces exposure to hazards.
- GHS pictogram
- A GHS pictogram is a standardized hazard symbol used on chemical labels to warn about specific dangers.
- Corrosive
- A corrosive substance can damage skin, eyes, metals, or other materials by chemical action.
- Flammable
- A flammable substance can catch fire easily when exposed to heat, sparks, or open flame.
- Safety Data Sheet
- A Safety Data Sheet is a document that lists a chemical's hazards, safe handling rules, first aid steps, storage needs, and disposal information.
Common Mistakes to Avoid
- Wearing goggles on the forehead instead of over the eyes. This is wrong because splashes and flying glass can reach the eyes without warning.
- Smelling chemicals directly from the container. This is wrong because vapors can irritate or poison you, so use wafting only when instructed.
- Pouring leftover chemicals back into the stock bottle. This is wrong because contamination can ruin the supply or cause an unexpected reaction.
- Cleaning a spill without reporting it first. This is wrong because the chemical may require a special spill kit, PPE, or evacuation procedure.
Practice Questions
- 1 A student needs 100.0 mL of 0.50 M HCl from a 2.0 M stock solution. Using C1V1 = C2V2, what volume of stock acid is needed, and how much water is added to reach the final volume?
- 2 A spill kit contains 750 g of absorbent. If each small spill requires 125 g of absorbent, how many small spills can the kit fully handle?
- 3 A bottle label shows the corrosive pictogram and the flammable pictogram. Describe the PPE, handling precautions, and storage choices that would be appropriate before using this chemical.