course 1. 63.546 u =atomic mass 3.4 grams / 63 grams Cu per mole = 0.05397moles 0.05397moles*6.02*10^23mol^-1= 3.25 *10^22 molecules 2. 6.5g Au/ 196.96655 g Au per mole=. 13454 moles Au . 13454 moles Au* 6.022 10^23 mol^-1=8.09910^22molecules 25.6g Ag/108.86655g per mole Ag= .24567 moles Ag .24567 moles Ag*6.022 10^23 mol^-1=1.479*10^23 molecules The silver ring has more molecules then the gold one. 3. (a) T (?)=5/9* [T(?)-32] T (?)=5/9 *(68?-32)=.20? (b) T (?)=9/5* T(?) +32 9/5* (1800?+32)= 3272? 4. 136?; 5/9* [T(?)-32] =5/9 *(136?-32)=5/9* (104)=57.78? -129?; 5/9* [T(?)-32] =5/9 *(-129?-32)= 5/9*(-161)=-89.44? 5. (a) T (?)=9/5* -15 +32=-27+32=5? (b) T (?)=5/9* (-15?-32)= 5/9* (-47)-26.11? 6. L1=11.82cm T1=0.0? L2=22.85cm T2=100? dL/dT=11.03cm/100?=.1103cm/1? a)16.70cm dL=16.70cm-11.82cm=4.88 dL/dT=.1103cm/1?=4.88cm/x 4.88cm=.1103cm*x 4.88cm/.1103cm=x=44.24? b) 20.50cm DL=20.50cm-11.82cm= 8.68cm dL/dT =.1103cm/1?=8.68cm/x 8.68cm=.1103cm*x= 8.68cm/.1103cm=x=78.69? 8. L=2.0m dT=5.0? α=0.2*10^-6(C? ? dL=αL0dT =0.2*10^-6(C? ^?*2.0m*5?=0.000002m or 2*10^-6 The coefficient of expansion of steel=12*10^-6 (C? ^? 12*10-6 (C?^?*2.0m= 24*10^-6. It is 12 times more then the alloy. 12. volume= 4/3*pi*r3 =(4/3)*pi*(8.75/2)^3=(4/3)*pi*(4.375)^3 =(4/3)*pi*(83.74)=350.769cm^3 dV= βVodT 1.0*10^-6*352.769cm^3*(200?-30?)=0.0596cm or 0.06cm 17.p= mass/volume dV= βVodT dp=-βpdT b) dT=-40?-25?=-65? dT=11.3*10^3