- When 1 litre of water is cooled from 4°C to 0°C, its volume _.?
(a) First decreases and then increases
(b) Remains the same
(c) Increases
(d) Decreases
Answer: (c)
Explanation
When 1 litre of water is cooled from 4°C to 0°C volume of water will start increasing this due to water’s unique property known as ‘Anomalous Expansion of Water’. Anomalous Expansion of Water occurs between 4°C to 0°C. The density of water is a maximum at 4 °C.
The anomalous expansion of water is an abnormal property of water whereby it expands instead of contracting when the temperature goes from 4o C to 0o C, and it becomes less dense. The density is maximum at 4 degree centigrade and decreases below that temperature as shown in graph.
Video Explanation - Which one of the following gases produces a red light when electricity flows through it??
(a) Helium
(b) Argon
(c) Nitrogen
(d) Neon
Answer: (d)
Explanation
A discharge of energetic electrons through the gas causes collisions of electrons with the gas atoms, resulting in electrons in the gas atoms being excited to higher energy states. The electrons then return to their normal (ground state) energies by emitting electromagnetic radiation. That is why you see colors
Video Explanation - Which of the following metals does not form amalgams??
(a) Zinc
(b) Copper
(c) Iron
(d) Magnesium
Answer: (c)
Explanation
A mixture or an alloy of mercury with a number of metals such as sodium, zinc, gold and silver as well as with some non-metals is known as amalgam. Dental amalgam is mixture of mercury and silver tin alloy.
So the Mercury needs to solvate iron atoms by incorporating the iron lattice which is extremely difficult to occur because the iron is extremely stable. This stability of the iron is because of its electronic configuration which doesn’t afford the transition metal Hg to make amalgam with iron.
Video Explanation - Which gas is typically produced when metal reacts with acids??
(a) Hydrogen
(b) Oxygen
(c) Hydrogen
(d) Nitrogen
Answer: (a)
Video Explanation - If helium and methane are allowed to diffuse out of the container under the similar conditions of temperature and pressure, then the ratio of rate of diffusion of helium to methane is:?
(a) 2 : 1
(b) 1 : 2
(c) 3 : 5
(d) 4 : 1
Answer: (a)
Video Explanation - One gram molecule of a gas at N.T.P. occupies 22.4 litres? This fact was derived from?
(a) Dalton’s theory
(b) Avogadro’s hypothesis
(c) Graham’s law
(d) Law of gaseous volume
Answer: (b)
Video Explanation - Find the fraction of the total pressure exerted by hydrogen if it is mixed with ethane in an empty container at 25℃?
(a) 15/16
(b)1/16
(c) 1/2
(d) 1
Answer: (a)
Video Explanation - The volume of 2.8 g of carbon monoxide at 27°C and 0.0821 atm is ____L?
(a) 30
(b) 0.3
(c) 30
(d) 1.5
Answer: (a)
Video Explanation
9.A radioactive rare gas is?
(a) Helium
(b) Krypton
(c) Radon
(d) None of these
Answer: (c)
Explanation
The known isotopes of helium contain from one to six neutrons, so their mass numbers range from three to eight. Of these six isotopes, only those with mass numbers of three (helium-3, or 3He) and four (helium-4, or 4He) are stable; all the others are radioactive, decaying very rapidly into other substances.
Video Explanation
- _ is the change from the solid state into the gaseous state.?
(a) Fusion
(b) Condensation
(c) Sublimation
(d) Vaporization
Answer: (c)
Explanation
Solids can be heated to the point where the molecules holding their bonds together break apart and form a liquid. The most common example is solid ice turning into liquid water. This process is better known as melting, or heat of fusion, and results in the molecules within the substance becoming less organized.
CONDENSATION is the process where water vapor becomes liquid. It is the reverse of evaporation, where liquid water becomes a vapor.
SUBLIMATION, in physics, conversion of a substance from the solid to the gaseous state without its becoming liquid. An example is the vaporization of frozen carbon dioxide (dry ice) at ordinary atmospheric pressure and temperature.
VAPORIZATION, conversion of a substance from the liquid or solid phase into the gaseous (vapour) phase. If conditions allow the formation of vapour bubbles within a liquid, the vaporization process is called boiling
Video Explanation
11.Which law states that the volume of an ideal gas at constant pressure is directly proportional to its absolute temperature??
(a) Boyle’s law
(b) Joule’s Law
(c) Avogadro’s law
(d) Charles’s Law
Answer: (d)
Video Explanation
- Helium gas is used in gas balloons instead of hydrogen gas because it is?
(a) Lighter than hydrogen
(b) More abundant than hydrogen
(c) More stable
(d) Non-combustible
Answer: (d)
Video Explanation
13.The best conductor of heat among liquids is??
(a) Alcohol
(b) Murcury
(c) Water
(d) Ether
Answer: (b)
Explanation
We know that most metals are good conductors of heat as solid at room temperature. But mercury is the only good conductor of heat in a liquid state due to its high coefficient of expansion. One more property of mercury that is its high boiling point makes it suitable for measuring high temperatures.
Video Explanation
- Maximum deviation from ideal gas behaviour is expected from __ gas.?
(a) CH4
(b) NH3
(c) N2
(d) None of these
Answer: (b)
Explanation
NH3
NH3 will show maximum deviation from ideal gas due to dipole-dipole attraction.
Video Explanation - Charles’s law is observed at:?
(a) constant volume
(b) constant pressure
(c) constant temperature
(d) constant volume and pressure
Answer: (b)
Video Explanation - Name the particles which make up matter.?
(a) Metals
(b) Atoms
(c) Non metals
(d) Metallide
Answer: (b)
Video Explanation - How can one state of matter be changed into another??
(a) By using electrolytes
(b) By absorbing radiating heat energy
(c) By increasing pressure
(d) By using acids and bases
Answer: (b)
Video Explanation - At the same temperature, the average molar kinetic energy of N2 and CO is?
(a) KE1 > KE2
(b) KE1 = KE2
(c) KE1 < KE2
(d) None of these
Answer: (b)
Video Explanation - Which of the following statements is correct??
(a) All metals are ductile
(b) Generally, metals are ductile
(c) All non-metals are ductile
(d) None of these
Answer: (b)
Video Explanation - _ solids consist of ordered three-dimensional arrays of a structural motif, such as an atom, molecule or ion?
(a) Amorphous
(b) Crystalline
(c) both
(d) None of these
Answer: (b)
Video Explanation - Which of the following statement is wrong for gases??
(a) Gases do not have definite shape and volume
(b) Mass of the gas cannot be determined by weighing a container in which it is contained
(c) Confined gas exert uniform pressure on the wall of the container in all directions
(d) Volume of the gas is equal to the volume of the container confining the gas
Answer: (b)
Video Explanation - The heat released at the time of condensation is called as?
(a) Sublimation heat
(b) Condensation Heat
(c) Latent Heat
(d) None of these
Answer: (c)
Video Explanation - Temperature which is same in both Celsius scale and Fahrenheit scale:?
(a) 0 Degree
(b) 32 Degree
(c) 40 F
(d) -40 Degree
Answer: (d)
Video Explanation - Which of the following figures does not represent 1 mole of dioxygen gas at STP??
(a) 16 grams of gas
(b) 22.7 litres of gas
(c) 6.022 × 1023 dioxygen molecules
(d) 11.2 litres of gas
Answer: (a)(d)
Video Explanation - Which of the following gases will have the highest rate of diffusion??
(a) O2
(b) CO2
(c) N2
(d) NH3
Answer: (d)
Video Explanation
