Honors Chemistry is designed for students who have demonstrated strong ability in previous science courses.
It spans several pages, but it is mostly revision and has been included as a reference for learners. You will need to decide, based on your class, about how much time you need to dedicate revising these topics, or whether you get your learners to read over the content and complete the activity at the end.
Can you remember learning about compounds in Gr. We will start this chapter by summarising and revising some of the main ideas about elements and compounds from Gr.
This should help us to link the new ideas in this chapter to what we already know. The particles that make up compounds Learners need to ionic formula writing activity made aware that compounds may occur as two types of structures, namely molecules and lattices: When a compound is made up entirely of non-metals CO2, H2O, or NH3, for examplethe smallest unit of that compound will be a molecule.
However, when a compound is made up of a metal and a non-metal NaCl, or CuO, for instancethe type of bonding in the compound is different. During bonding, the metal and non-metal atoms exchange electrons to form ions. Due to opposite charges attracting, these ions pack together in vast three-dimensional crystals or lattices, rather than forming simple molecules.
In this section we have included a brief mention of crystal lattices to avoid the misconception later that NaCl and other ionic compounds consist of molecules.
Learners should know that NaCl, for instance, consists of a regular arrangement of sodium and chloride atoms combined in a 1: The particles of a compound always consist of two or more atoms.
In Physical Sciences Gr. In some cases they can form molecules. Other compounds consist of atoms which are arranged in a regular pattern called a crystal lattice. The molecules of a compound always consist of two or more different kindsof atoms, like the molecules of water in the following diagram.
Compounds that form crystal lattices consist of many atoms, but they always combine in a fixed ratio. For example, in sodium chloride table saltthere is one chlorine atom for every sodium atom in the crystal.
A sodium chloride crystal lattice consisting of sodium purple and chloride green atoms in a fixed ratio. From the diagram of the water molecules and the sodium chloride lattice above, we can see that a compound is not simply a mixture of elements.
A mixture of the elements hydrogen and oxygen would look like this: A mixture of hydrogen and oxygen molecules. Why are the hydrogen and oxygen atoms paired in the diagram above? Before we answer that question, here is an important reminder: Elements are made up of just one kind of atom.
Some elements exist as diatomic molecules. Can you see that the water molecules in the diagram above are all identical?
That brings us to the next point about compounds. The atoms in molecules and lattices are combined in a fixed ratio In water, for example, one oxygen atom O has combined with two hydrogen atoms H.
All water molecules are exactly the same in this respect. All water molecules consist of one O atom and two H atoms and this gives water its specific properties. Any other combination of hydrogen and oxygen atoms would NOT be water. For example, hydrogen peroxide consists of the same elements as water hydrogen and oxygen but the ratio is different: The hydrogen peroxide molecule consists of two O atoms and two H atoms.
This gives hydrogen peroxide different properties to water. In the crystal lattice of black iron oxide, there is one iron Fe atom for every oxygen O atom.
The next important point about compounds is the following. Each compound has a unique name and formula Water can be represented by the formula H2O. The formula tells us that two hydrogen atoms H are combined with one oxygen atom O in a molecule of water.
What is the formula of hydrogen peroxide? Can you remember the name of the compound with the formula CO2? Remember to take notes as you discuss things in class!Net ionic equations are equations that show only the soluble, strong electrolytes reacting (these are represented as ions) and omit the spectator ions, which go through the reaction barnweddingvt.com you encounter net ionic equations on the SAT II Chemistry test, you’ll need to remember the following solubility rules, so memorize them!
An activity coefficient is a factor used in thermodynamics to account for deviations from ideal behaviour in a mixture of chemical substances. In an ideal mixture, the microscopic interactions between each pair of chemical species are the same (or macroscopically equivalent, the enthalpy change of solution and volume variation in mixing is zero) and, as a result, properties of the mixtures can.
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In a chemical reaction, chemical equilibrium is the state in which both reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the system. Usually, this state results when the forward reaction proceeds at the same rate as the reverse reaction.
Tweet. This site has many resources that are useful for students and teachers of Chemistry 11 in BC as well as any introductory high school chemistry course in the US or anywhere else in the world. Raining vinegar In some places in world the rain water has become so polluted with chemicals that it is like vinegar.
This type of rain is called acid rain. Pure water is neutral and has a pH of 7.