Chm151 Review for Test2, Ch2&3 SP23.pdf

Chm151, Review for Test 2, Ch2&3, SP23 Things to know/be able to do. I pulled some of these from the review questions in the textbook at the end of the chapter, but picked the ones I want you to focus on. Chap02 Atoms and Elements State and explain the law of conservation of mass. Describe the plum...

Chm151, Review for Test 2, Ch2&3, SP23 Things to know/be able to do. I pulled some of these from the review questions in the textbook at the end of the chapter, but picked the ones I want you to focus on. Chap02 Atoms and Elements State and explain the law of conservation of mass. Describe the plum-pudding model of the atom. Describe Rutherford’s gold foil experiment and his resulting nuclear model of the atom. List the three subatomic particles that compose atoms and give the basic properties (mass and charge) of each (you did this in the Atoms and Isotopes lab) Know the difference between Z (the atomic number) and A (the mass number) for an element. What are isotopes? What is percent natural abundance of isotopes, and how are they determined? Be able to calculate the average atomic mass of an element given the isotopes and abundances. What is an ion? A cation? An anion? How do you predict the charges of ions formed by main-group elements? What is a mole? Be able to do calculations of number of atoms in a given mass of an element, or number of moles, and vice-versa. Why is the mass corresponding to a mole of one element different from the mass corresponding to a mole of another element? Chap03, Matter, Measurement, and Problem Solving Chemical Bonds – Ionic vs Molecular (Covalent), know the two main differences between these two types of compounds: Ionic Molecular (Covalent) Composition metal + non-metal 2 or more non-metals Electrons Transferred, opposite Shared, forms molecules ions attract Ionic and Molecular compounds Elements in ionic compounds always go together to give a neutral compound. Thus the charges of the ions can tell us the number of each element in the compound. Simple or Roman Numeral naming. Elements in covalent compounds can go together in many different ways. Thus prefixes are used to tell us the number of each element in the compound. Naming Acids (know the naming rules for binary acids and oxoacids (“-ate” to “ic acid”, “ite” to “ous acid”) and hydrates. Be able to calculate the molar mass of a compound. Chemical Composition Molecular formula vs empirical formula (lowest whole number ratios of the elements) Empirical formula problems- we did several of these in class, working from either masses of elements in a compound or percent by mass of elements in a compound. Also, given the molar mass, be able to calculate the molecular formula from the empirical formula. I found a little mnemonic for this online that some students have found helpful: My High School chem teacher taught us a rhyme to help remember how to find empirical formulas! I say it in my head every time to make it easier. (assume 100 g) "Mass to moles Divide by small Times till whole Its not hard at all!"