Science Quiz on Liquids and Mixtures

Science Safety 1.1

• Hazard symbols are used to warn of potential dangers

• Hazardous materials have labels showing a symbol

• The shape of the symbol indicates the type of hazard

• A yellow triangle indicates caution

• An orange diamond indicates warning

• A red octagon indicates danger

• The picture inside the symbol indicates the specific type of hazard

• Examples of hazards include:

  • Exploding bomb (for explosion or reactivity hazards)
  • Flame (for fire hazards)
  • Flame over circle (for oxidizing hazards)
  • Gas cylinder (for gases under pressure)
  • Corrosion (for corrosive damage to metals, as well as skin, eyes)
  • Skull and crossbones (causing death or toxicity with short exposure to small amounts)
  • Health hazard (may cause or suspected of causing serious health effects)
  • Exclamation mark (may cause less serious health effects or damage the ozone layer)
  • Environment (may cause damage to the aquatic environment)
  • Biohazardous Infectious Materials (for organisms or toxins that cause diseases in people or animals)
  • Electrical

WHMIS

• WHMIS stands for Workplace Hazardous Materials Information System
• WHMIS symbols were designed to protect people using potentially harmful materials at work
• WHMIS is a system for labeling potentially harmful products

Beirut Explosion (August 2020)

• The Beirut Explosion in August 2020 was caused by improper storage of ammonium nitrate

Lab Safety Rules

•  Read all written instructions carefully before starting any activity
• Listen attentively and follow instructions carefully
• Wash hands thoroughly after each activity and after handling chemicals
• Wear required personal protective equipment (PPE): safety goggles, gloves, apron
•  Think before touching anything. Equipment might be hot and substances may be dangerous
• Smell a substance by fanning the smell toward you with your hand, keep your nose away from the substance directly
• Do not taste anything in the lab
• Secure your hair and clothing during the activity
• Never pour liquids into containers held in your hands
• Place test tubes into a rack before pouring substances into them
• Clean up any spills immediately as instructed by your teacher
• Look at test tubes and containers from the sides, not the top
• Do not use broken or cracked glassware
• Follow the instructions that your teacher has provided for disposing broken glassware
• Label all containers with their contents
• Report all spills and accidents promptly to the teacher

Properties of Fluids

• A fluid is a substance that flows and takes the shape of its container. This can be a liquid or a gas
• Fluids exhibit the property called flow
• Examples of fluids include water, natural gas, milk, and air.
• Solids do not flow. Granulated solids may form a pile, but they will not flow on their own

Particle Model of Matter

• All matter is composed of tiny particles in constant motion. The particles of matter have spaces between them
• In liquids and gases, the particles have large spaces between them, and the attractive forces are weaker, so the particles can slide past one another.
• In solids, the particles have small spaces between them and the attractive forces are stronger, so the particles cannot slide past one another.

Lubricants

• Fluids are often used as lubricants to reduce friction between moving parts
• Example: you can apply a lubricant to a door hinge to reduce the friction

Slurries

• A slurry is a mixture of water and solid particles
• Slurry technology is useful for moving solids by mixing them with water
• Example: transporting oil sands in pipelines

Matter Classification

• Matter can be classified into pure substances (elements, compounds) and mixtures
  • Pure substances cannot be broken down into simpler forms
  • Mixtures are combinations of two or more pure substances
    • Mechanical mixtures (Heterogeneous mixture): the components are easily recognizable
    • Solutions (Homogeneous mixture): the components are fully mixed
• Example: Chocolate chip cookie is a heterogeneous mixture; Saltwater is a homogeneous mixture

Concentration and Solubility

• Concentration is a description of the amount of solute compared to the amount of solvent
• Concentration can be described qualitatively: unsaturated, saturated, and supersaturated
• Saturated: maximum amount of solute dissolved in the solvent
• Solubility Rate of substances depend on 3 factors:
  • Type of solute
  • Type of solvent
  • Effect of temperature (Raising the temperature increases solubility for solids and liquids, but decreases solubility for gases)
• Dissolving is the process where solute particles mix completely with solvent particles
• Insolubility refers to substances that do not mix with a solvent
• Substances in a solution are separated if they are insoluble and if they are soluble.