chemistry notes 2024

Experimental Design Common Laboratory Apparatus Measuring Mass Name of Apparatus Accuracy of Apparatus All readings should be in Electronic mass balance 0.01 g 2 decimal places Digital stopwatch 0.01 s Nearest seconds Alcohol thermometer 0.5 degrees Celsius 1 decimal place (nearest .0 or .5) Measuring Volume Name of Apparatus Accuracy of Apparatus All readings should be in Measuring cylinder Half of the smallest division 1 or 2 decimal places (depending on the apparatus)

Burette 0.05 cm^3 2 decimal places Pipette 0.01 cm^3 1 decimal place Gas syringe 0.1 cm^3 1 decimal place Name of Apparatus Accuracy of Apparatus All readings should be in Collection of Gas The method used to collect a gas depends on the physical properties of the gas: Solubility in water Density: Less dense or denser than air? Take the molar mass of air to be approximately 30 g/mol Gas Collection Methods Water Displacement Suitable for gases that are insoluble in water

Downward Delivery Suitable for gases that are more dense than water Upward Delivery Methods for Drying Gases Using Concentrated Sulfuric Acid

Suitable for gases that are acidic/neutral in nature For Method 1 explain why the inlet tube is inserted into the concentrated sulfuric acid while the outlet tube needs to be above the concentrated sulfuric acid The inlet tube needs to be in the concentrated sulfuric acid so that gas needs to be bubbled into the acid to remove the water vapour. The outlet tube needs to be above the concentrated sulfuric acid so that the dry gas can escape. Using Calcium Oxide Suitable for gases that are basic/neutral in nature Using Fused Calcium Chloride

Suitable for gases that are acidic/alkaline/neutral (except for ammonia) For Method 3, explain what it meant by "fused" and why ammonia gas cannot be collected using this method. "Fused" means anhydrous (does not contain water) This method cannot be used to collect ammonia gas because ammonia would react with calcium chloride

Kinetic Particle Theory What is Kinetic Particle Theory? Matter is defined as any substance that has mass and volume. Kinetic Particle Theory The kinetic particle theory states that: All matter is composed of tiny particles that are in a constant state of motion (have kinetic energy.) Properties Properties Solid Liquid Gases Forces of Attraction between particles Strong attractive forces between particles Relatively strong attractive forces between particles BUT weaker than those in solid. Weak forces of attraction between particles

Arrangement of Particles Particles are orderly arranged in a fixed position. Hence, they have a fixed shape. It has a fixed volume as a solid cannot be compressed since its particles are already very close to one another with very little space between the particles. Particles are NOT held in fixed positions. They are arranged in a disorderly manner. Hence, they DO NOT have a fixed shape. Particles of a liquid are farther away from one another than a solid. However, they are still packed quite closely together. Hence, a liquid cannot be compressed and has a fixed volume. Particles are NOT held in fixed positions. Particles are spread far apart from one another. Hence, they DO NOT have a fixed shape. Movement of Particles Particles are unable to move freely. Particles are able to move freely and slide across one another. Particles move rapidly in high speeds in any direction. Properties Solid Liquid Gases

Energy of Particles Particles vibrate about its fixed positions Particles of a liquid have more kinetic energy than particles of a solid in the same substance. Particles have high kinetic energy. Properties Solid Liquid Gases Changes in Temperature Heating and Cooling of Particles Heating/Cooling Change in distance between particles Change in movement of particles Change in arrangement of particles Heating Distance between particles increases and particles are further apart from one another Vibrates faster and more vigorously From sliding over one another within the liquid to free to move anywhere in the container Cooling Distance between particles decreases and particles get closer. Vibrates slower and less vigorously From sliding over one another witin the liquid to vibrating at fixed positions Heating Curve

States of Matter Present Temperature (increasing, decreasing or remain constant) Movement of Particles Arrangement of Particles Strength of Attractive Forces of Attraction Between Particles Solid Increasing Particles are gaining kinetic energy and vibrate faster Particles are arranged in an orderly manner Particles are close to one another with strong forces of attraction between them. Solid and Liquid Constant Particles continue to vibrate, without increase in kinetic energy Particles are starting to slide over one another Energy is taken in to overcome the forces of attraction between particles Liquid Increasing particles are gaining kinetic energy and vibrate faster Particles are sliding over one another randomly Strong forces of attraction between particles

Liquid and Gas Constant Particles continue to vibrate, without increase in kinetic energy Particles moving further away in a random manner Energy is taken in to overcome the forces of attraction Gas Increasing Particles are gaining kinetic energy and vibrate faster. Particles travel at high speeds Particles are very far away and free to move randomly Weak forces of attraction States of Matter Present Temperature (increasing, decreasing or remain constant) Movement of Particles Arrangement of Particles Strength of Attractive Forces of Attraction Between Particles Brownian Motion The kinetic model of matter states that all matter is made up of a large number of small particles (e.g. atoms, molecules, ions) which are in continuous and random motion. Definition of Diffusion