Cheatography

# Chem MT 1-6 Cheat Sheet by rubycitalan

### The Scientific Method

 Chemistry is the science that deals with the materials of the universe and the changes that these materials undergo. Steps: 1. State the problem and collect data (make observ­ations) 2. Formulate hypotheses. A hypothesis is a possible explin­ation for the observ­ation. 3. Preform Experi­ments. Gather new inform­ation that allows us to decide whether the hypothesis is supported by the new inform­ation we have learned

### Measur­ements and Calcul­ations

 Scientific notation expresses a number as a product of a number between 1 and 10 and the approp­riate power of 10. Ex. (100= 1.0×102 , 0.010=­1.0×10-2) If the decimal is moved to the left, the power of 10 is positive ; if the decimal is moved to the right, the power of 10 is negative.

### Unit Prefixes ### Signif­icant Figures

 The numbers recorded in a measur­ement are called signif­icant figures. 1. Nonzero integers always count as signif­icant figures. Ex. (4567 has four nonzero integers that count as signif­icant figures.) 2. Zeros. a. leading zeros never count as signif­icant figures. Leading zeros are all zeros that precede nonzero integers. b. captive zeros always count as signif­icant figures. Captive zeros are zeros that fall in between two nonzero digits. c. trailing zeros are sometimes signif­icant figures. Trailing zeros are zeros right at the end of a number. They are only signif­icant if the number is written with a decimal. (Ex. The number 100 only has one SF 1 ; but the number 100. has three SF. 3. Exact Numbers never limit the number of signif­icant figures in a calcul­ation. Signif­icant figures also apply to scientific notation.

### Temper­ature Conversion ### TC Equations

 Temper­ature in Kelvins = Temper­ature in Celsius + 273 Temper­ature in Celsius = Temper­ature in Kelvin - 273 Temper­ature in Fahrenheit = 1.80( Temper­ature in Celsius) +32 Temper­ature in Celsius = Temper­ature in Fahrenheit - 32 / 1.80

### Density, Mass, and Volume ### Elements and Compounds

 An element is a substance that cannot be broken down into other substances by chemical means. When elements combine, they form compounds, which are substances that can be broken down into elements by chemical means.

### Pure Substances and Mixtures

 A pure substance is either an element or compound. A mixture can be defines as something that has variable compos­ition. Mixtures can be classified as either homoge­neous or hetero­gen­eous. A homoge­neous mixture is the same throug­hout. This type of mixture is also called a solution. A hetero­geneous mixture contains regions that have different properties from those of other regions. These mixtures can be separated through distil­lation and filtration.

### Mixtures ### Dalton's Atomic Theory

 1. Elements are made of tiny particles called atoms. 2. All atoms of a given element are identical. 3. The atoms of a given element are different from those of any other element. 3. Atoms of one element can combine with atoms of other elements to form compounds. A given compound always has the same relative numbers and types of atoms. 4. Atoms are indivi­sible in the chemical process. Atoms are not created nor destroyed in chemical reactions. A chemical reaction simply changes the way the atoms are grouped together.

### Atom Structure ### Isotopes ### Periodic Table ### Ions

 An ion is an atom or molecule with a net electric charge due to the loss or gain of one or more electrons. A cation is a positively charged ion; an ion that has lost electrons. An anion is a negatively charged; an atom that has gained electrons. Alkali Metals are the most reactive metals that can form cations easily by only needing to lose one valence electron. Halogens are the most reactive nonmetals that can form anions easily by only needing to gain one valence electron. Noble Gasses have 8 valence electrons so they are already stable. An ionic bond is a chemical bond resulting from the attraction between oppositely charged ions. A chemical compound must have a net charge of 0 (zero)

### Ionic charges ### Common Simple Cations and Anions

 Cation Name Anion Name H+ hydrogen H- hydride Li+ lithium F- fluoride Na+ sodium Cl- chloride K+ potassium Br- bromide Cs+ cesium I- iodide Be2+ beryllium O2- oxide Mg2+ magnesium S2- sulfide Ca2+ calcium Ba2+ barium Al3+ aluminum Ag+ silver Zn2+ zinc

### Common Type II Cations

 Ion Systematic Name Older Name Fe3+ iron(III) ferric Fe2+ iron(II) ferrous Cu2+ copper(II) cupric Cu+ copper(I) cuprous Co3+ cobalt­(III) cobaltic Co2+ cobalt(II) cobaltous Sn4+ tin(IV) stannic Sn2+ tin(II) stannous Pb4+ lead(IV) plumbic Pb2+ lead(II) plumbous Hg2+ mercur­y(II) mercuric Hg22+ mercury(I) mercurous
Mercury(I) ions always occur bound together in pairs to form Hg22+.

### Nomenc­lature ### Common Polyatomic Ions. ### Rules for Naming Acids

 If the anion does not contain oxygen, the acid is named with the prefix hydro- and the suffix -ic attatched to the rootname of the element. Ex. HCl= hydro-chlor-ic acid 2. When anions contain oxygen, the acid name is formed from the root name of the central element of the anion or the anion name with the suffix of -ic or -ous. When the anion name ends in -ite, the suffix -ic is used. (Ex. H2SO4 = SO42-(sulfate) = Sulfric Acid) When the anion name ends in -ite, the suffix -ous is used in the acid name. (Ex. H2SO3 = SO32- (sulfite) = Sulfurous acid)

### Chemical Equations

 We represent a chemical reaction by writing a chemical equation in which the chemical reactions (the reactants) are shown to the left of an arrow and the chemicals are formed by the reaction (the products) are shown to the right of the arrow. In the process of balancing equations is that atoms are conserved in a chemical reaction. The identities (formulas) of the compounds must never be changed in balancing a chemical equation.

### Balancing Equations

 Step 1 Read the descri­­ption of the chemical reaction. Step 2 Write the unbalanced equation that summarizes the inform­ation from step 1. Step 3 Balancing the equation by inspec­tion, starting with the most compli­cated molecule. Proceed element by element to determine what coeffi­cients are necessary so that the same number of each type of atom appears on both the reactant and the product side. Step 4 Check to that the coeffi­cients used, give the same number of each type of atom on both sides of the arrow. Also check to see that the coeffi­cients used are the smallest integers that give the balanced equations. This can be cone by determ­ining whether all coeffi­cients can be divided by the same integer to give a set of smaller integer coeffi­cients.