16/09/2023
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👉Fundamental Concepts in Chemistry
**Q. 1.** The soul of chemistry is its dealing with:
- a. Internal structural changes in matter
- b. Composition of matter
- c. Properties of matter
- d. Composition and properties of matter
- **Answer:** (d)
**Q. 2.** All of the following statements are incorrect for 20 mol of hydrogen peroxide except:
- a. it has 20 mol of hydrogen atoms
- b. it has 30 mol of oxygen atoms
- c. it has 80 mol of atoms
- d. 30 mol of hydrogen atoms
- **Answer:** (c)
**Q. 3.** If the proton number of two atoms is the same, then it can be concluded that:
- a. they are isotopes
- b. compounds of both with Cl2 will be similar in reactivity towards other compounds
- c. both have the same colors
- d. both have the same melting points
- **Answer:** (b)
**Q. 4.** A chemist poured lemon juice on soil, the idea that he may have in his mind is that:
- a. there may be a possibility of a chemical reaction
- b. lemon juice is dangerous to health
- c. lemon juice is dangerous to health
- d. water should be preferred over lemon juice for drinking
- **Answer:** (a)
**Q. 5.** Dr. Khan has discovered two isotopes of an element with atomic number 119. The relative abundance of isotopes 119Uue300 and 119Uue305 is 70% and 30% respectively. The average atomic weight of Uue is:
- a. 301.5 a.m.u
- b. 302.5 a.m.u
- c. 303.5 a.m.u
- d. 304.5 a.m.u
- **Answer:** (a)
**Q. 6.** Which of the following is not related to a.m.u:
- a. gram
- b. kilogram
- c. microgram
- d. gram/lit
- **Answer:** (d)
**Q. 7.** The number of significant figures in 0.00200 is:
- a. two
- b. three
- c. five
- d. one
- **Answer:** (b)
**Q. 8.** All of the following statements are incorrect except:
- a. precision and accuracy should go side by side in a scientific work
- b. scientific work must be precise, accuracy is not essential
- c. scientific work must be accurate, precision is not essential
- d. +calculations must be made before any experiment
- **Answer:** (a)
**Q. 9.** Empirical formula and formula unit of an ionic compound:
- a. are always similar
- b. are always different
- c. may be similar or different
- d. ionic compounds don’t have any empirical formula
- **Answer:** (c)
**Q. 10.** Copper (II) oxide is mixed with an organic compound during combustion analysis. The purpose is:
- a. to carry out complete combustion
- b. to reduce the economy of the process
- c. to reduce the time for completion of the reaction
- d. all of the above
- **Answer:** (a)
**Q. 11.** Bismark brown is a dye. Its molar mass is 228.3 g/mol. When the dye was analyzed by a scientist, it was found that it contains 30.68% nitrogen. How many nitrogen atoms are there in each Bismark brown molecule?
- a. 6
- b. 5
- c. 4
- d. 3
- **Answer:** (b)
**Q. 12.** The mass of 2 moles of sodium hydroxide will be:
- a. 2 g
- b. 20 g
- c. 40 g
- d. 80 g
- **Answer:** (d)
**Q. 13.** “A” compound always consists of the same elements combined in the same fixed ratio. The statement is:
- a. a hypothesis
- b. a fact
- c. a law
- d. an observation
- **Answer:** (c)
**Q. 14.** Compound having the highest boiling point among the following is:
- a. HF
- b. HCl
- c. HBr
- d. HI
- **Answer:** (d)
**Q. 15.** Islamian genius investigated that the amount of heat required to raise the temperature of 11 grams of water from 30oC to 31oC is:
- a. one calorie
- b. a little bit greater than one calorie
- c. a little bit less than one calorie
- d. never equal to one calorie
- **Answer:** (c)
**Q. 16.** An atom is:
- a. the smallest indivisible particle in an element
- b. the smallest particle of an element which can undergo a chemical reaction
- c. the building block of an element
- d. always smaller than a molecule
- **Answer:** (b)
**Q. 17.** 10 moles of H2O contains:
- a. 100 moles of bonds
- b. 100 moles of electrons
- c. 30 atoms
- d. 25 moles of hydrogen bonds
- **Answer:** (b)
**Q. 18.** The volume of one kilogram of water at 4oC is equal to one liter. The temperature of water is kept at 4oC because water:
- a. has no dissolved gases at this temperature
- b. has maximum density at this temperature
- c. the polarity of the water molecule is least at this temperature
- d. the dipole moment has a maximum value at this temperature
- **Answer:** (b)
**Q. 19.** A compound contains two elements X and Y percentage of X is 20% (At.wt = 40) and that of Y is 80% (At.wt = 80). The empirical formula of the compound is:
- a. XY2
- b. X2Y
- c. X3Y
- d. XY
- **Answer:** (a)
**Q. 20.** A piece of paper is burnt in air, the gas produced is passed through distilled water. The pH of the water solution will be:
- a. 1
- b. 7
- c. 2.1
- d. 6.8
- **Answer:** (d)
**Q. 21.** Which of the following is a substance?
- a. sea water
- b. brass
- c. tap water
- d. graphite
- **Answer:** (d)
**Q. 22.** Freezing point of a substance is a temperature at which a liquid substance is converted to solid, it is:
- a. always lower than its melting point
- b. usually a little lower than its melting point
- c. always higher than its melting point
- d. exactly the same as its melting point
- **Answer:** (b)
**Q. 23.** Number of covalent bonds in 10 mol of carbon tetrachloride is:
- a. 2.4 x 10^25
- b. 40
- c. 4 x 10^24
- d. 6.4 x 10^21
- **Answer:** (a)
**Q. 24.** A student subtracted 0.00055 from 10.2345678 and reported the result as 10.23401. But his friend told him that the result was wrong. What is the correct result?
- a. 10.234017
- b. 10.2340178
- c. 10.234
- d. 10.23
- **Answer:** (d)
**Q. 25.** The following statement contained in a student’s laboratory report is a conclusion:
- a. a gas is liberated
- b. color of the gas is greenish yellow
- c. oxide of the gas is strongly acidic
- d. the gas is chlorine
- **Answer:** (d)
**Q. 26.** If 10g each of uranium and hydrogen are converted into energy according to the equation E = mc^2:
- a. energy obtained from uranium will be too much greater than that of hydrogen
- b. energy obtained from hydrogen will be a little bit less than that of uranium
- c. energy obtained from hydrogen and uranium will always be exactly equal
- d. diamond
- **Answer:** (c)
**Q. 27.** A student analyzed a sample of sea water and found that it contained 2.3g of NaCl, 0.005g of MgSO4, 0.234g of CaCl2, and 60.12g of H2O. Total mass of the sample is:
- a. 62.659
- b. 62.65
- c. 62.70
- d. 65.7
- **Answer:** (d)
**Q. 28.** A 50.00 mL sample of a cough mixture prepared by a pharmacist was found to have a mass of 46.0g. What is the density (in g/mL) of this mixture. Stated to the correct number of significant figures?
- a. 0.92
- b. 0.920
- c. 0.9200
- d. 1.087
- **Answer:** (b
**Q. 29.** Ozone (O3) filters the cosmic rays of sunlight. How many oxygen atoms are there in 0.2 mole of ozone (O3, molar mass 48.0 g/mol)?
- a. 6.02 x 10^22
- b. 6.02 x 10^23
- c. 3.61 x 10^23
- d. 6 x 10^23
- **Answer:** (c)
**Q. 30.** On heating, the hydrated salt CaSO4, xH2O loses its water of crystallization. In an experiment it was found that when 0.2 mol of the hydrated salt was heated 0.10 mol of water was lost. What is the molecular formula of the hydrated compound?
- a. CaSO4
- b. CaSO3. ½ H2O
- c. CaSO4.H2O
- d. CaSO4.2H2O
- **Answer:** (b)
**Q. 31.** Zirconium chloride reacts with magnesium to produce Zirconium. The process is called Knoll process.
- ZrCl4 + 2Mg → Zr + 2MgCl2
- How many moles of Zr would be produced if 0.2 mol of Mg metal is used in the reaction?
- a. 0.1
- b. 0.01
- c. 0.20
- d. 0.05
- **Answer:** (a)
**Q. 32.** To***co contains a poisonous alkaloid called Ni****ne. The molecular formula of ni****ne is C10H14N2 (molar mass = 162.23g). The mass percentage of nitrogen in ni****ne is?
- a. 4.32%
- b. 8.23%
- c. 12.4%
- d. 17.3%
- **Answer:** (d)
**Q. 33.** A sample of an ionic compound contains 2.82 g Na, 4.35 g Cl, and 7.83 g O. The empirical formula of this compound is:
- a. NaClO2
- b. NaClO3
- c. NaClO
- d. NaClO4
- **Answer:** (d)
