Test 1  Practice                       Chem 20                         Name____________________

1    How many significant figures are in the following numbers.

    a) .00623 _______    c) 7.657x105  _______    e) 3000.00 _______

    b) 45.80 _______    d) 0.660x10-5

2    Round the foloowing numbers to three significant figures and express them in scientific notation.

    a) 2499526    ______________    d) .00003579    _______________

    b) 68351    ________________    e) 5645000       _______________

    c) 545.996x10-5 _____________

3    Make the following conversions, showing mathematical setups and expressing the answer to the proper number of significant figures.

    a) 72.0 km to cm

    b) 75.0 ºC to ºF

    c) 9.6x105 cm/second to miles/hr

4    What volume of mercury has a mass of 2300. g? Give answer to the proper number of significant figures and express the answer in scientific notation.
 
 
 

5    5.00 g of an unknown substance at 50.0ºC is dropped into a coffee cup calorimeter containing 100.g of water at 20.0ºC. the final temperature of the water and the unknown is 25.0 ºC. What is the specific heat of the unknown? Hint: q(lost)=q(gained)
 

6    Give the IUPAC name of the following molecule in lower case letters.

  1. Mn(HAsO3)2
  2. Co(H2PO4)2
  3. Ni(ClO4)2
  4. NH4C2H3O2
  5. H2N2O2
  6. H3PO3
  7. K2SO3
  8. H3AsO2
  9. N2O3
7    Give the Formula for the following substances:
  1. hydrofluoric acid
  2. Aluminum monohydrogen phosphate
  3. cobalt(II) iodide
  4. cobalt(II) iodite
  5. cobalt(IV) iodate
  6. Manganese(II) hydrogen sulfide
  7. Manganese(II) hydrogen sulfite
  8. Magnesium hydrogen sulfide
  9. sulfurous acid
  10. sulfuric acid
  11. ammonium chromate
  12. silver periodate
  13. silver periodate
  14. iron(II) oxalate
  15. diphosphorous pentoxide
8
Symbol Atomic 
number		 Number of
protons		 Number of 
neutrons		 Number of 
electrons		 Charge
55    +2
    Fe
26		          

  
 		    8       10    10  

  
 		       35     44       -1

9    A wedding ring is placed into a graduated cylinder containing 20.0 ml of water. The new total volume of  in the graduated cylinder is 21.1 ml. The density of gold is 19.6 g/ml and the density of brass is 8.6 g/ml. How could a prospective bride tell the difference between a gold plated brass wedding ring and a solid gold wedding ring? What are the possible numeric outcomes for the ring? Show all units.
 

10    Define the following:
a) Matter
b) Physical change
c) Chemical change
d) Phase change
e) Homogeneous mixture
f) Heterogeneous mixture
g) Solution

11    What are the properties of a:
    a)  metal
    b) nonmetal
    c) metalloid
    d) semimetal
    e) solid
    f) liquid
    g) gas

12    How are conservation of energy and mass related?

13    How much energy is given off when 1.00 g of matter is completely converted into energy?

14    What is the relative mass and charge of protons, neutrons and electrons?
 
Protons Neutrons Electrons
Ralative mass      
Relative charge      

15    What three things did Rutherford's gold leaf experiment determine?

16    State the Law of Definite Proportion.
17    State the Law of Multiple Proportions.