For Chemistry Tutorials

Menu
## Heat Temperature and Thermal Expansion Exam2 and Problem Solutions

**Heat Temperature and Thermal Expansion Exam2 and Problem Solutions**

**1.** If Celsius thermometer shows the temperature of air 30^{0}C, find the temperature of air in Fahrenheit thermometer.

**T(K)=T(C)+273**

**T=30+273=303 ^{0}K**

**C/100=(F-32)/180**

**30/100=(F-32)/180**

**F=86 ^{0}F**

**2.** Find heat required to make 5g ice at -20^{0}C to water at 30^{0}C. (c_{ice}=0,5cal/g.^{0}C, L_{ice}=80cal/g, c_{water}=1cal/g.^{0}C)

**Heat required to make ice at -20 ^{0}C to ice at 0^{0}C ;**

**Q _{1}=m.c_{ice}.ΔT=5.0,5.20**

**Q _{1}=50cal.**

**Heat required to make it melt;**

**Q _{2}=m.L_{ice}=5.80**

**Q _{2}=400cal.**

**Heat to make it water at 30 ^{0}C;**

**Q _{3}=m.cwater.ΔT=5.1.30**

**Q _{3}=150cal**

**Q _{total}=Q_{1}+Q_{2}+Q_{3}=50+400+150=600cal**

**3.** Two taps fill the water tank with different flow rates. Tap A fills the tank in 1 hour and tap B fills the tank in 3 hour If we open two taps together, find the final temperature of the water in the tank.

**Flow rates of taps;
V _{A}=3V_{B}**

**3m.c.(T-10)=m.c(50-T)**

**T=20 ^{0}C**

**4.** When we decrease the temperatures of the rods ΔT, relation between the final lengths of rods becomes; L_{1}<L_{2}<L_{3}. Find the relation between α_{A}, α_{B} and α_{C}.

**Since change in length of the rod 1 is larger than the rod 2;**

**α _{A}<α_{B}**

**Since change in length of the rod 2 is larger than the rod 3;**

**α _{C}<α_{A}**

**α _{C}<α_{A}<α_{B}**

**5.** Length vs. temperature graph of A, B and C is given below. Find the relation between λ_{A}, λ_{B} and λ_{C}.

**Slope of the graph=ΔL/ΔT=L _{0}.λ**

**Initial length of A is larger than C but slopes of them are equal, so;**

**λ _{C}>λ_{A}**

**B and C have same length but slopes of them are different.**

**λ _{B} >λ_{C}**

**λ _{B} >λ_{C}>λ_{A}**

Author: Mrs. Şerife (Erden) SARICA

© Copyright www.PhysicsTutorials.org, Reproduction in electronic and written form is expressly forbidden without written permission of www.PhysicsTutorials.org. Privacy Policy