Paper 2

• When measuring the rate of a reaction, the units used are volume in centimeters cubed per minute and time in seconds and mass in grams per second.
• In the first graph, the volume of carbon dioxide being produced is increasing, while in the second graph, the mass being lost is decreasing.
• To find the rate at a particular point in a reaction, draw a tangent, which is a straight line that touches the curve just at that point, and then work out the gradient of that line.
• The rate of reaction can be compared at different points in a reaction.
• Different ways to follow a reaction include looking at the loss of mass, color change, or change in volume.
• When following a reaction by looking at the loss of mass, it is important to collect the gas produced, either in a measuring syringe or an inverted measuring cylinder.
• When following a reaction by looking at the color change, it is important to constantly wash things out to avoid contamination.
• The higher the pressure or concentration, the faster the rate of reaction, as there are more particles in a fixed volume, increasing the likelihood of a successful collision.
• Instead of just going straight from the reactant to product, there's an activation energy hump that the reaction has to get over.
• A catalyst lowers the activation energy, making it easier for the reaction to take place.
• The surface area of a lump of something, such as a sugar cube, can limit the number of particles available to react.
• Before starting an experiment, it's important to consider the potential for errors due to gas in the measuring cylinder.
• The rate of reaction can be affected by temperature, as particles with more energy can move around faster and lead to more frequent successful collisions.
• Adding large marble chips to a gas experiment can cause the bubbles to collect in the measuring cylinder, leading to errors.
• The larger the surface area, the faster the rate of reaction, as more particles are available to react.
• It is important to be careful with sodium thiosulfate and hydrochloric acid reaction, as gases start to come off at temperatures above 60 degrees and it can irritate hands.
• The same person should always measure the rate of reaction to ensure that differences in people's eyes don't affect the results.
• One way to collect the gas is by using an inverted measuring cylinder and putting a delivery tube through there.
• The environmental impacts of a product's manufacture, use, and disposal need to be considered in a life cycle assessment.
• Alkenes have double bonds and are unsaturated, with the general formula Cn H2n.
• Bond can be used by more than one carbon or hydrogen when we're counting things.
• In organic chemistry, hydrogen always makes one bond, and carbon always makes four bonds.
• Bacteria and plants are used to remove bacteria and unwanted mineral ions from water.
• The first four alkenes are ethene, propene, butene, and pentene.
• Metals such as copper, gold, and silver are very important on Earth but are rare and need to be developed from low-yield ores.
• Bioleaching involves adding bacteria to a large body of water with metal ions dissolved in it, which the bacteria leach out as copper ions.
• A bond is a pair of electrons that are covalently shared.
• Bioleaching and phytomining are methods used to extract rare metals from low-yield ores.
• Chlorine and fluoride are added to water for disinfection and tooth and bone protection.
• Phytomining involves growing plants, such as broccoli, in soil with low yields of copper, which are then burned and the ash used for electrolysis.
• It is important to be careful about the gas already in the measuring cylinder.
• Climate change affects animals and plants as well as humans.
• Australia is having its hottest Christmases ever, while the UK is having its coldest Christmases ever, due to climate change.
• Only a small percent of the water on Earth is suitable for us to drink, so we need to remove salt from it, which is known as desalination, and make it safe to drink, or potable water.
• Human activities contribute to the production of carbon dioxide, which is a major pollutant.
• Climate change is causing deserts, countries, and farmland to dry out completely, and is melting ice poles, which is bad for polar bears as they live on these blocks of ice.
• Sulfurdioxide, when it goes into the atmosphere, dissolves in the clouds and comes back down as acid rain, which is harmful to animals, plants, and statues.
• As the temperature changes, the top of the mountain, which perhaps used to be under snow, is now available for habitation by new animals and plants.
• Large levels of smog and global dimming are prevalent in developing countries due to carbon monoxide, nitrogen oxides, and water vapor.
• Carbon dioxide levels in the atmosphere are predicted to increase, leading to increased global warming.