All Free Chemistry MCQs with Answers
Every Chemistry question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
13,720 questions Β· page 667 of 686
- A. Very small size of Nitrogen
- B. Pyramidal structure of NH3
- C. Enhanced electronegative character of Nitrogen
- D. Enhanced electropositivity of nitrogen
Explanation: The boiling point of ammonia (NH3) is higher compared to the hydrides of other Group V elements because of its stronger intermolecularβ¦
Correct answer: Enhanced electronegative character of Nitrogen- A. CH2O
- B. CH3CHO
- C. (CH3-CH2)3N
- D. All of the above
Explanation: All of them cannot form hydrogen bonds among themselves
Correct answer: All of the above- A. Acetic acid
- B. Water
- C. Ethyl alcohol
- D. Diethyl ether
Explanation: Among the options provided, water (H2O) has the highest boiling point. This is because water molecules are held together by strongβ¦
Correct answer: Water13324. A mixture of 50gH2 and 50gHe has a total pressure of 1.5atm. What is the partial pressure of H2 gas?
- A. 1.0 atm
- B. 2.0 atm
- C. 1.5 atm
- D. 3.0 atm
Explanation: Partial Pressure = Mole Fraction x Total Pressure Find moles of hydrogen and helium; moles = mass/Mr; moles = 50/2 = 25 moles of hydrogenβ¦
Correct answer: 1.0 atm- A. 1.0atm
- B. 2.0atm
- C. 1.5atm
- D. 3.0atm
Explanation: Find moles of hydrogen and helium; moles = mass/Mr; moles = 50/2 = 25 moles of hydrogen moles= 50/4 = 12.5 moles of helium Total moles =β¦
Correct answer: 1.0atm13326. If the pressure and temperature (k) of two liters of CO2 are doubled the volume of CO2 would become:
- A. 5 liters
- B. 4 liters
- C. 8 liters
- D. 2 liters
Explanation: As PV=nRT or V =nRT/PUsing P'=2P and T'=2T, we getV'= 2nRT/2PV'= nRT/PV'= VSo , the volume will be 2 litres.
Correct answer: 2 liters- A. The number of molecules in the gas
- B. Avogadro's number
- C. The number of kilo-moles
- D. The number of molecules per unit volume
Explanation: The ideal gas law can be written in terms of the number of molecules of gas: PV = nRT, where P is pressure, V is volume, T is temperatureβ¦
Correct answer: The number of molecules in the gas- A. (298)(750)(50)/(40)(765)
- B. (298)(750)(40)/(50)(765)
- C. (298)(765)(50)/(750)(40)
- D. (40)(750)/(298)(50)(765)
Explanation: PV=nRTAccording to the ideal gas equation: PV = nRT. P1V1/T1=P2V2/T2 OrT2=P2V2T1/ P1V1 So T2 Should be solved as follows T2β¦
Correct answer: (298)(765)(50)/(750)(40)- A. Avogadro constant; Boltzmann constant
- B. Avogadro constant; Molar gas constant
- C. Total number of molecules; Boltzmann constant
- D. Total number of molecules; Avogadro constant
Explanation: In the ideal gas equation pV = NkT, 'N' represents the total number of molecules of gas, while 'k' represents the Boltzmann constant.
Correct answer: Total number of molecules; Boltzmann constant- A. 10 atm, 25 atm, 15 atm
- B. 10 atm, 15 atm, 25 atm
- C. 25atm, 10 atm, 15 atm
- D. 15 atm, 25 atm, 10 atm
Explanation: Simplify 20:30:50 to get 10:15:25To find the partial pressures of each gas, we need to calculate the pressure contributed by each gasβ¦
Correct answer: 10 atm, 15 atm, 25 atm- A. Pπ = ππ T
- B. ππ = ππ T
- C. πππ = ππ T
- D. All of the above
Explanation: The correct equation to describe the behavior of ideal gases under standard conditions is PV = nRT.
Correct answer: Pπ = ππ T- A. They have two functional groups
- B. They show both acidic and basic characteristics
- C. They are the basic units of proteins
- D. They do not exist in solid state
Explanation: Amino acids exist as zwitterions, which are molecules that have both positive and negative charges but are overall neutral.
Correct answer: They do not exist in solid state- A. Gaseous matter
- B. Solid matter
- C. Liquid matter
- D. all have the same magnitude
Explanation: Internal energy is defined as the sum of kinetic and potential energies associated with the random motion of atoms in a substance, andβ¦
Correct answer: Gaseous matter13334. The sum of all possible kinds of energies of all atoms, molecules or ions within a system is called:
- A. Test
- B. Internal energy
- C. Potential energy
- D. Bond energy
Explanation: Internal energy refers to the total energy of all the atoms, molecules, or ions within a system.
Correct answer: Internal energy- A. internal energy
- B. Work
- C. Enthalpy
- D. All of the above
Explanation: When we talk about the change in heat at constant volume, we are actually measuring the internal energy of the system.
Correct answer: internal energy- A. More than NaBr crystal
- B. Less than NaBr crystal
- C. Equal to NaBr crystal
- D. NaCl crystal doesn't conduct electric current
Explanation: In solid form, NaCl does not conduct electricity because its ions are locked in place within the crystal lattice and cannot move freely.
Correct answer: NaCl crystal doesn't conduct electric current- A. High melting point
- B. Deform when struck
- C. Fragility
- D. Crystalline
Explanation: Fragility refers to the tendency of a substance to break or shatter easily.
Correct answer: Fragility- A. ionic and covalent
- B. covalent and ionic
- C. covalent and coordinate covalent
- D. ionic and coordinate covalent
Explanation: The correct answer is 'ionic and covalent'. PbClβ is ionic because lead is in a +2 oxidation state, leading to electron transfer and ionicβ¦
Correct answer: ionic and covalent- A. ionic compounds
- B. polymeric compounds
- C. covalent compounds
- D. coordination compound
Explanation: Fajan's rule explains that small, highly charged ions have high polarizing power due to their charge density.
Correct answer: covalent compounds- A. The ionic bonds are non-directional in character
- B. The crystals of covalent compounds are made up of molecules
- C. The covalent bonds are rigid and non-directional
- D. Ionic compounds have high melting points and boiling points
Explanation: Covalent bonds are directional because they involve specific orientations of shared electron pairs, leading to definite molecular shapes.
Correct answer: The covalent bonds are rigid and non-directional