Tag: chemistry

Questions Related to chemistry

By what factor does water expand when converted into vapour at $100^o$C and $1$ atm pressure? The density of liquid water at $100^o$C and $1$ atm is $0.96$g $cm^{-3}$?

chemistry materials around us and different types of houses materials around us matter and its states different states of matter

  1. $815$

  2. $2000$

  3. $1630$

  4. $500$

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Correct Option: A

When water is cooled it contracts until it reaches ______ and then it starts expanding.

chemistry materials around us and different types of houses materials around us matter and its states different states of matter

  1. ${37^0}C$

  2. ${40^0}C$

  3. ${0^0}C$

  4. ${4^0}C$

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Correct Option: D
Explanation:

Though substances contract on cooling, water expand when cooled beyond ${4^0 C}$. This is known as anomalous behavior of water. The density of water is maximum at $4^0$$C$

A solid shape has _____ dimensions and so occupies _______.

chemistry materials around us and different types of houses materials around us matter and its states different states of matter

  1. three, space

  2. two, space

  3. one, space

  4. no, space

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Correct Option: A

Which of the following cannot change, in a physical change?

chemistry materials around us and different types of houses materials around us matter and its states different states of matter

  1. Volume

  2. Pressure

  3. Chemical composition

  4. Temperature

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Correct Option: C
Explanation:

In a physical change the chemical composition of a substance does not change. 


For example conversion of water into steam where composition remain same i.e. $H _2O$.

Volume, pressure and temperature are the physical properties.

The state in which molecular attractions are very strong is:

chemistry materials around us and different types of houses materials around us matter and its states different states of matter

  1. solid

  2. liquid

  3. gas

  4. none of these

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Correct Option: A
Explanation:

Solids are densely packed due to its  high intermolecular attractions so they are highly incompressible but liquid has less intermolecular attractions compared to solid.But gases have very less intermolecular attractions.So they are loosely packed.

 Space occupied is given by :

chemistry materials around us and different types of houses materials around us matter and its states different states of matter

  1. solid

  2. density

  3. matter

  4. weight

  5. volume

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Correct Option: E
Explanation:

Space occupied is given by volume which is generally measured in litres. Other units of volume include $dm^3$, gal and mL.


Hence the correct option is E.

Gases do not have a definite shape because:

chemistry materials around us and different types of houses materials around us matter and its states different states of matter

  1. molecules exert no force of attraction or repulsion upon one another

  2. molecules exert force of attraction

  3. molecules exert force repulsion upon one another

  4. both b and c

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Correct Option: A
Explanation:

The molecules exert no force of attraction or repulsion upon one another. I.e., the molecules are independent of each other. This is the reason gases do not have a definite shape.

A solid cube of iron whose edge is 4 inches weighs 20.8 lbs. Determine the specific gravity of this sample of iron, if water weighs 62.4 pounds per cubic foot?
chemistry materials around us and different types of houses materials around us matter and its states different states of matter

  1. $4.5$

  2. $5.2$

  3. $9.0$

  4. $27$

  5. $324$

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Correct Option: C
Explanation:

$4$ inches $=$ $0.333$ foot


Since it is a solid cube, its volume is given by the formula $(side)^3$, that is, here its volume is $(0.333)^3$, that is $0.0369$ cubic foot.


Mass of the solid cube is $20.8$ pounds

Density $=$$\dfrac{Mass}{Volume}$

Thus, the density of the solid cube is $\dfrac{20.8}{0.0369}$, that is $563.68$ pounds per cubic foot.

Mass of water is $62.4$ pounds per cubic foot.

Thus, density of water is $\dfrac{Mass}{Volume}$, that is $\dfrac{62.4}{1}$, that is $62.4$ pounds per cubic foot.

Specific gravity of the solid iron  $= \dfrac {Density\ of\ solid\ iron} {Density\ of\ water}$

Thus, specific gravity of the iron is $=$ $\dfrac{563.68}{62.4}$, that is $9.033 \approx\ 9$

Hence, the correct option is C.

 Mass per unit volume can be defined as:

chemistry materials around us and different types of houses materials around us matter and its states different states of matter

  1. volume

  2. weight

  3. density

  4. matter

  5. none of the above

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Correct Option: C
Explanation:

Mass per unit volume can be defined as density. For example : when 1 g of water has volume of 1 mL, the density of water will be 1 g/mL.
Density $\displaystyle = \dfrac {\text {mass}}{\text {volume}}$

Which of the following is the most precise for measuring the volume of a liquid?

chemistry materials around us and different types of houses materials around us matter and its states different states of matter

  1. Test tube

  2. Graduated cylinder

  3. Burette

  4. Volumetric flask

  5. Beaker

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Correct Option: D
Explanation:

Volumetric flask is the most precise for measuring the volume of a liquid.


When the values of different measurements are close to each other as well as to average value, such measurements are called precise.

Hence the correct option is D.