Important equations and exam questions

• Independent variable:

  The variable that is being tested
• Dependent variable: The variable that is measured or changed by the independent variable.
• Control variable: A variable that is kept constant throughout the experiment to ensure that it does not affect the results.
• vaccinations can help treat diseases and decrease the nunber of people who get them
• Antibiotics are only used to treat bacterial infections and therefore are prescribed to patients with bacterial infections.
• Antibiotics work by either killing bacteria or preventing It from reproducing.
• Examples of bacterial infections could be: Gonorrhea, Tuburculosis, step throat and Q fever
• Sexually transmitted diseases are caused by pathogens that are spread through sexual contact.
• Density = mass / volume
• Mass = kg
• Volume = m^3
• Density = kg/m^3 = mass/volume
• Flourine is a non-metal
• Flourine (F^2) is a non-metal and is covalently bonded
• oxygen is a gas at room temperature
• Why is a simple covalent molecule a gas at room temperature?


  Because the forces between simple covalent molecules are weak as they have low melting and boiling point
• What type of bonding and structure do I have in F^2?

  Flourine is a non-metal and forms covalent bonds and forms a simple covalent molecule.
• What type of bonding and structure do I have in NaF?

  Sodium Fluoride is made by a metal (sodium) and non-metal (Fluoride) and is therefore an Ionic compound.
• An insulator does not easily allow heat to pass through it.
• Metals are on the left of the periodic table.
• Non-metals are on the right of the periodic table
• Name the acid and the metal oxide used to produce zinc nitrate.

  Nitric acid and zinc oxide
• Reactivity Series: The metals potassium, sodium, lithium, calcium, magnesium, zinc, iron and copper can be put in order of their reactivity from their reactions with water and dilute acids.
• When sodium is heated, it emits a lilac flame
• Electronic structure of oxygen refers to the arrangement of electrons in the outermost shell of an oxygen atom.
• Dot and cross diagram of a molecule of water." This refers to a visual representation showing how the atoms in a water molecule share electrons
• Dot and cross diagram of a molecule of water

  the dot and cross diagram of water (H2O), two hydrogen atoms each share one electron with the oxygen atom, resulting in a covalent bond between each hydrogen and oxygen atom
• Dot and cross diagram of a water molecule

  
• Some examples of metals include iron, copper, aluminum, gold, and silver. 
• Halogens are a group of non-metal elements in Group 17 of the periodic table. They are highly reactive and include elements such as fluorine, chlorine, bromine, and iodine
• Halogens have 7 electrons in their outer shell. 
• Flourine is a gas at room temperature because it has weak intermolecular forces between its molecules
• Reason for the size of a potassium atom compared with the size of a sodium atom.

  The reason for the larger size of a potassium atom compared with a sodium atom is that as you move down a group in the periodic table, the number of electron shells increases, leading to a larger atomic size
• One atom of argon contains 18 protons and 22 neutrons.
• Dot and cross diagram of a Flourine molecule

  
• In an experiment, it's important to keep variables such as the volume of solutions, the mass of substances, the concentration of solutions, the starting temperature, and the duration of stirring consistent to ensure accurate and reliable results.
• Halogens are found in group 7 in the periodic table
• Noble gases are in group 8 of the periodic table
• when chlorine reacts with sodium, it forms sodium chloride, which is common table salt.
• ionisation energy: This is the energy required to remove an electron from an atom