Aspirin , C9H8O4 , is the active ingredient in many prescription pain relievers. Its molar mass is 148 g/mol. a. If the tablets in a bottle contain a total of 38g of Ibuprofen , how many moles of aspirin are in the bottle? b. How many molecules of aspirin are in the bottle? c. What is the total mass in grams of carbon in 38g of aspirin?

.     (3 pts each) Carry out the following operations, and express the answer with the appropriate number of significant figures:

a.      1.24056 + 75.8 =

1.24056

             +75.8      

              77.04056  -> Round to tenths place:  77.0

b.     320.55 – (6104.5/2.3) =

   320.55

 -2654.1304

 -2333.580  -> round to HUNDREDS place: -2300 or -2.3 x 103

c.      (0.0045 x 20,000.0) + (2813 x 12) =

    90.000

+33756.000

 33846.000 -> round to TEN THOUSANDS place: 34000 or 3.4 x 104

The all-time record lowest temperature ever recorded on this planet is –57.63 oC (recorded on July 21, 1983 in Vostok, the Russian Antarctic station).

a.     Express this temperature in oF.

oF = (9/5)oC + 32

   = (9/5)(-57.63) + 32 = -71.734 oF à -71.73 oF

b.     Express this temperature in Kelvins (K).

K = oC + 273.15

  = -57.63 + 273.15 = 215.52 K à 215.52 K

3.     (10 pts) A 26.27-g sample of a solid is placed in a flask. Toluene, in which the solid is insoluble, is added to the flask so that the volume of the solid and liquid together is 50.00 mL. The solid and liquid toluene together weigh 52.65 g. The density of toluene at the temperature of the experiment is 0.864 g/mL. What is the density of the solid?

solid + toluene =   52.65 g

          solid =   26.27 g

Mass of toluene =   26.38 g toluene

     26.38 g toluene x 1 ml toluene     = 30.53241 mL toluene

             0.864 g toluene

solid + toluene =   50.00 mL

        toluene =   30.53241 mL

          solid =   19.46759 mL

density of the solid = 26.27 g

                      19.46759 mL

                     = 1.34942 g/mL à 1.35 g/mL

4.     (16 pts) Fill in the gaps in the following table:

Symbol

52Cr3+

107Ag+

75As3-

Protons

24

47

33

Neutrons

28

60

42

Electrons

21

46

36

Net Charge

3+

1+

3-

.     (2 pts each) From this list of elements: Ar, H, Ga, Al, Ca, Br, Ge, K, O; pick the one that best fits each of the following descriptions. You may use each element only ONCE.

a.     an alkali metal:                           K                 

b.     an alkaline earth metal:              Ca              

c.     a noble gas:                                Ar              

d.     a halogen:                                  Br              

e.     a metalloid:                                Ge              

f.      a nonmetal listed in group IA:      H                 

g.     a metal that forms a 3+ ion:        Al              

h.     a nonmetal that forms a 2- ion:   O                 

i.       an element that resembles aluminum:   Ga    

6.      (1 pt each) Give the atomic symbol for the following elements:

a.     calcium:                  Ca               

b.     sodium:                  Na               

c.     mercury:                 Hg               

d.     lead:                       Pb               

3 pts each) Write a complete, balanced chemical equation for each of the following reactions:

a.     Solid calcium carbide (CaC2) reacts with water to form an aqueous solution of calcium hydroxide and acetylene gas (C2H2).

HOPE THIS HELPS YOU OUT :3