PRACTICE EXAM FOR 3 Quarter

1.  mixture
2.  2 significant figures
3.  92p, 92e, 146n
4.  plum pudding model by Thompson, billiard ball model by Dalton, electrons flying around outside the nucleus but not in orbits by Rutherford, electrons is specific orbits by Bohr, electrons in orbitals is the modern model
5.  IV means Iron loses 4 electrons as it forms into a cation

6.  same number of particles, Avogodro's Hypothesis (should be a law, but no one can count that high!)
7.  3Mg + N₂ --->  Mg₃N₃
8.  A
9.  circle around AB, CD, EF.  put a square around BC and square DE
10.  2-8-7-3
 
11.  Ioinic compounds: circle NaCl, CaO, MgO, Na₂O
12.  alloy:  mixture of 2 or more metals, or metal with non-metal, formed by melting metal first.  
               Creates new substance with better properties for certain conditions.  
Coordinate covalent bond: special sharing of 2 electrons by one part of a molecule, as in carbon monoxide.  Isotope: when 2 or more kinds of chemically identical atoms exist because they have different numbers 
             of neutrons, and therefore different masses.  That is their ONLY difference.
13.skip this one of course.
14.  asymmetrical and polar = H₂O,   symmetrical and non-polar = CO₂ and H₂
15.  glucose to carbon dioxide MOLE RATIO is 1/6.  12 moles glucose/ x moles CO₂.  X= 72 moles CO₂
 
16.  molar mass of CuSO₄·5 H₂O = 64+32+4(16)+5(18) = 250 g/mole
       90 g water/ 250 g CuSO₄·5 H₂O X 100% = 36% water only; 100 g X .36 = 36 grams water

17.  products are AlPO_{4 (S)} + NaCl _(AQ)

18.  dots diagrams.  2nd and third require brackets to indicate ionic bonding!

19.  NaOH / NaCl mole ratio is 1/1 ratio.      75g NaOH = 1.875 moles.    
   
      1.875 moles NaCl = 1.875 x 58 g/mole = 
 
                 108.75 g   correct sig figs make answer 3 sig figs, 109 grams.

20.  TWO formulas, heat water, and phase change     q=mC∆T, q=mHv, 

          20,482 J + 113,000 J  = 133,482 J. 
                                                        Correct sig figs is just 3 sig figs so answer can be 133 kJ