Chemistry Exam 1 – Flashcards
Unlock all answers in this set
Unlock answers| How to calculate an average atomic mass? |
example: 98.93 % 12^c & 1.07% 13^C masses are 12 amu, and 13.00335.
(0.9893)(12amu) + (0.0107)(13.00335amu) = 12.01amu a.k.a Atomic Weight |
| How much does 1 amu = ? |
| 1.66054 x 10-24 |
| What is Avogadro's Number? |
| 6.0221421 x 1023 |
| [image] |
| [image] |
Significant Figures:
Addition and Subtraction the result has the ____ number of decimal places as the measurment with the ______ decimal places. |
| Same number of decinmal places as the measurment with the Fewest decimal places |
| 7 Diatomic Molecules |
| H,N,O,F,Cl,Br,I |
How to calculate mass number
ex: 12C |
| Number of Protons + Neutrons |
How to calculate Atomic number
ex. 6C |
| Number of Protons or Electrons |
| What is an Isotope? |
| Same number of protons but different numbers of neutrons. |
| What subatomic particle defines an element? |
| Proton |
| Name the three types of radiation. |
| aAlpha bBeta gGamma |
| Which 2 types of radiation are bent by an electric field> |
| Both aAlpha+ and bBeta- |
| What is Dalton's 1st postulate? |
| Each element is composed of extremely small particles called atoms. |
| What is Dalton's 2nd postulate? |
| All atoms of a given element are identicle to one another in mass and other properties, but the atoms of one element are different from the atoms of all other elements. |
| What is Dalton's 3rd Postulate? |
| The atoms of one element cannot be changed into atoms of a different element by chemical reactions; atoms are neither created nor destroyed in chemical reactions. |
| What is Dalton's 4th postulate? |
| Compounds are formed when atoms of more than one element combine; a given compound always has the same relative number and kind of atoms. |
| What law can we conclude from Dalton's 4th Postulate? |
| The law of constant composition |
| What is the law of costant composition? |
| In a given compound, the relative numbers and kinds of atoms are constant. |
| What law can we conclude from Dalton's 3rd postulate? |
| Low of conservation of mass a.k.a. law of conservation of matter |
| What is the law of conservation of mass/matter? |
| The total mass of materials present after a chemical reaction is the same as the total mass present before the reaction. |
| Law of Multiple proportions |
It states that the masses of one element which combine with a fixed mass of the second element are in a ratio of whole numbers postulate 3 |
| What is the formula to calculate oF to oC |
| oC = 5/9 (oF -32) |
| What is the formula to convert oC to oF? |
| oF=9/5 (oC) +32 |
Rule #1 of significant figures
Zeros between nonzero digits |
Always important ex. 1005 4 sig figs ex. 1.03 3 sig figs |
Rule # 2 signifigant figures
Zeros at the beginning of a number |
NEVER significant
(merley indicate the position of the decimal point)
ex. 0.02 one significant figure |
Rule #3 of significant figures
Zeros at the end of a number |
Are significant if the number contains a decimal point ex. 0.0200 3 significant figures ex. 3.0 2 significant figures |
Significant figures:
In any measurment that is poroperly reported, all nonzero digits are ____ |
| Significant |
| How do you get the Formula Weight? |
The sum of the atomic weights of each atom in it's chemical formula.
ex.12 C atoms = 12(12.0amu) = 144.0amu 22 H atoms = 22(1.0) = 22.0amu 11 O atoms = 11(16.0 amu) = 176.0 amu Total: 342.0 amu (Formula Weight) |
| What is a molecule? |
| 2 Or more atoms are joined together in specific shapes |
| Pure substance |
| Distinct properties and a composition that does not very from sample to sample. |
| Intensive properties |
Temperatue, melting point, and density (do not depend on quantity) |
| Extensive properties |
(depend on the quantity of the sample)
mass and volume |
| What is a chemical reaction? |
| Substance transforming into a chemically different substance. |
| How do you calculate Molecular Weight? |
If the chemical formula is that of that of a molecule, then the formula weight is also called the moecular weight.
ex. glucose C6H12O6 MW :6(12.0amu)+12(1.0amu)+6(16.0amu)=180amu |
Percent Composition from Formulas
|
%element =
(Number of atoms of that element) (atomic weight of element)
Formula weight of compound
x 100% |
Estimating Numbers of Atoms
Ex. Without using a calculator, arrange the following samples in order of increaasing numbers of carbon atoms:12g 12C, 1 mol C2H2, 9 x 1023 molecules of CO2. |
1. Analyze- We are given amounts of different substances expressed in grams, moles, and a number of molecules and asked to arrange the samples in order of increasing numbers of C atoms.
2. Plan- To determine the number of C atoms in each sample, we must convert g 12C,1 mol C2H3 and 9 x 1023 molecules CO2 all to numbers of C atoms. To make these conversions, we use the definition of mole and Avogadro's number.
3. Solve- A mole is defined as the amount of matter that contains as many units of the matter as there are C atoms in exactly 12 g of 12C. Thus, 12g of 12C contains 1 mol of C atoms (that is 6.02 x 1023 atoms). One mol of C2H2 molecule, this sample contains 12 x 1023 C atoms. Because each CO2 molecule contains one C atom, the sample of CO2 contains one C atom, the CO2 contains
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| Ammonium Ion |
| NH4+ |
| Copper(I) or Cuprous ion |
| Cu+ |
| Cobalt(II) |
| Co2+ |
| Iron(II) or ferrous ion |
| Fe2+ |
| Mercury(I) or mer-curous ion |
| Hg22+ |
| Lead(II) or plumbous ion |
| Pb2+ |
| Manganese(II) or manganous ion |
| Mn2+ |
| Tin(II) or stannous ion |
| Sn2+ |
| Mercury(II) Mercuric ion |
| Hg2+ |
| Nickel(II) or nickelous |
| Ni2+ |
| Chromium(III) or chromic ion |
| Cr3+ |
| Iron(III) or Ferric ion |
| Fe3+ |
| Hydrogen Ion |
| H+ |
| Lithium Ion |
| Li+ |
| Sodium Ion |
| Na+ |
| Potassium Ion |
| K+ |
| Cesium |
| Cs+ |
| Silver Ion |
| Ag+ |
| Magnesium Ion |
| Calcium Ion |
| Ca2+ |
| Stronium Ion |
| Sr2+ |
| Barium ion |
| Ba2+ |
| Zn2+ |
| Cadmium ion |
| Cd2+ |
| Aluminum Ion |
| Al3+ |
