Physics

Thermal Properties of Matter

274 Questions

Thermal properties of matter examine how substances react to heat, covering concepts like temperature, specific heat, and phase changes. This topic is regularly tested in the physics and general science sections of competitive exams. Use this collection to solve numericals on heat transfer, thermal equilibrium, and melting points.

Heat transfer and mixingMelting and freezing pointsThermal expansion and densityTriple point of waterCarnot cycle applications

Thermal Properties of Matter Questions

Multiple choice physics calorimetry heat exchange calorimeter measuring thermal quantities by the method of mixtures

1 kg of water at $20^{\circ}C$ is, mixed with 800 g of water at $80^{\circ}C$. Assuming that no heat is lost to the surroundings. Calculate the final temperature of the mixture.

  1. $24.44^{\circ} C$
  2. $46.67^{\circ} C$
  3. $44.44^{\circ} C$
  4. $54.44^{\circ} C$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$mc\theta _1 + mc\theta _2 = mc\theta _0$
since c is constant, assuming water is heated from $0^o C$
(1000)(20) + (800)(80)= (1800)$\theta _0$
20000+64000= 84000=1800$\theta _0$
$\theta _0= 46.67^o C$
hence the finale temperature in $\theta _0=46.67^o$
Multiple choice physics calorimetry heat exchange calorimeter measuring thermal quantities by the method of mixtures

The temperature of equal masses of three different liquids A, B, and C are $12^o C$,$19^o C$ and $28^o C$ respectively. The temperature when A and B are mixed is $16^oC$ and When B and C are mixed is $23^o C$. The temperature when A and C are mixed is:

  1. $18.2^ C$
  2. $22^ C$
  3. $20.3^ C$
  4. $24.2^ C$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

let $m _1=m _2=m _3=m$
Let $s _1,s _2,s _3$ be the respective specific heats of the three liquids.
When A and B are mixed, temperature of mixed = $16^o C$
A heat gained by A = heat lost by B
$\therefore ms _1(16-12)=ms _2(19-16)$
$4s _1=3s _2$.......(i)
When B and C are mixed , temperature of mixture$=23^o C$.
As heat gained by B = heat lost by C,
$ms _2(23-19)=ms _3(28-23)$
$\therefore 4s _2=5s _3$......(ii)
From (i) and (ii) , $=\dfrac{3}{4}s _2=\dfrac{15}{16}s _3$
When A and C are mixed, suppose temperature of mixture$=t$
Heat gained by A = Heat lost by C
$ms _1(t-12)=ms _3(28-t)$
$\dfrac{15}{16}s _2(t-12)=s _3(28-t)$
$15t-180=448-16t$
$31t=448+180=628$
$t=\dfrac{628}{3}=20.3^o C$

Multiple choice chemistry metals reaction of metals reactions of metals chemical properties of metals

The piece of sodium melts in water at:

  1. $98^oC$
  2. $97.8^oC$
  3. $93^oC$
  4. $97^oC$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The piece of sodium melts in water at, $\displaystyle 97.8^oC$
Sodium reacts with cold water and gives sodium hydroxide and hydrogen gas.
$\displaystyle 2Na + 2H _2O \rightarrow 2NaOH + H _2$
The reaction is exothermic and releases the heat. The heat released melts Na. Then Na may disappear.  
The heat may burn hydrogen with an orange flame.

Multiple choice

What is the density of ice in glaciers?

  1. 0.917 g/cm^3

  2. 0.934 g/cm^3

  3. 0.958 g/cm^3

  4. 0.981 g/cm^3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The density of ice in glaciers is typically around 0.917 g/cm^3.

Multiple choice

What is the approximate temperature difference required between the warm surface waters and the cold deep waters for OTEC to be feasible?

  1. 5-10 °C

  2. 15-20 °C

  3. 25-30 °C

  4. 35-40 °C
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

The approximate temperature difference required between the warm surface waters and the cold deep waters for OTEC to be feasible is 20-25 °C.

Multiple choice

What is the specific heat of seawater?

  1. 1.0 J/g °C

  2. 4.18 J/g °C

  3. 3.9 J/g °C

  4. 2.1 J/g °C
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The specific heat of seawater is approximately 3.9 J/g °C, which means it takes 3.9 joules of energy to raise the temperature of one gram of seawater by one degree Celsius.

Multiple choice

What is the specific heat of seawater at a salinity of 35 parts per thousand (ppt)?

  1. 3.9 J/g °C

  2. 4.0 J/g °C

  3. 4.1 J/g °C

  4. 4.2 J/g °C
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

At a salinity of 35 ppt, the specific heat of seawater is approximately 4.0 J/g °C.

Multiple choice

What is the approximate specific heat of seawater at a temperature of 20 °C and a salinity of 35 ppt?

  1. 3.95 J/g °C

  2. 4.05 J/g °C

  3. 4.15 J/g °C

  4. 4.25 J/g °C
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The specific heat of seawater at 20 °C and a salinity of 35 ppt is approximately 4.05 J/g °C.

Multiple choice

Which physical parameter of water is measured in degrees Celsius or Fahrenheit?

  1. pH

  2. Turbidity

  3. Temperature

  4. Electrical Conductivity
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Temperature is a physical parameter of water that measures the degree of hotness or coldness and is expressed in degrees Celsius or Fahrenheit.

Multiple choice

What is the freezing point of pure water?

  1. 0 °C

  2. 1 °C

  3. 2 °C

  4. 3 °C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The freezing point of pure water is 0 °C or 32 °F.

Multiple choice

What is the freezing point of seawater with a salinity of 35 parts per thousand (ppt)?

  1. -1.8 °C

  2. -1.9 °C

  3. -2.0 °C

  4. -2.1 °C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The freezing point of seawater with a salinity of 35 ppt is -1.8 °C or 28.8 °F.

Multiple choice

What is the freezing point of seawater at a depth of 1000 meters?

  1. -1.9 °C

  2. -2.0 °C

  3. -2.1 °C

  4. -2.2 °C
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The freezing point of seawater at a depth of 1000 meters is -2.1 °C or 28.2 °F.