Question

An unknown mass of each substance, initially at 25.0 ∘C, absorbs 1920 J of heat. The final temperature is recorded. Find the mass of each substance. You may want to reference (Pages 259 - 264) Section 6.4 while completing this problem.

Answer 1

Answer: mass for Pyrex glass 84.21g

mass for sand 61.6g

mass for ethanol 41.32g

mass for water 62.07g

Explanation

By definition specific heat is the amount of heat required to change the temperature of 1 kg mas by 1°C

Q=mcΔT is formula for specific heat

Q is heat transfer

m is mass

ΔT is change in temperature

c   is specific heat

c of Pyrex glass= 0.75 j/g°C

c of sand = 0.84 j/g°C

c of ethanol= 2.42 j/g°C

c of water = 4.18 j/g°C

now we will make M(mass) the subject, so equation becomes

m=Q/cΔT

for

pyrex glass Tf=55.4°C

m=1920/(55.4-25)*0.75

m=84.21g {after cutting J(joules) and °C we are left with g(grams)}

for

sand Tf=62.1°C

m=1920/(62.1-25)*0.84

m=61.6g {after cutting J(joules) and °C we are left with g(grams)}

for

ethanol Tf=44.2°C

m=1920/(44.2-25)*2.42

m=41.32g  {after cutting J(joules) and °C we are left with g(grams)}

for

water Tf=32.4°

m=1920/(32.4-25)*4.18

m=62.07g  {after cutting J(joules) and °C we are left with g(grams)}

i hope you understand the solution, thank you.