1st Review Key PDF

1. Which of the following is a physical change? A. Rusting of iron B. Combustion of magnesium ribbon C. Burning of candle D. Melting of wax 2. Most rubbing alcohol is made from isopropyl alcohol or isopropanol in water. Which of the following would describe its che...

1. Which of the following is a physical change? A. Rusting of iron B. Combustion of magnesium ribbon C. Burning of candle D. Melting of wax 2. Most rubbing alcohol is made from isopropyl alcohol or isopropanol in water. Which of the following would describe its chemical properties? A. Density B. Boiling point of 82.5⁰ C C. Flammability D. Melting point of -89⁰ C 3. CuSO4 is a salt formed by treating CuO with H2SO4. It forms as large, bright blue crystals containing five water molecules (CuSO4∙5H2O) and is known in commerce as blue vitriol. If this compound is dissolved completely in water, which statement is correct? A. The copper compound is the solvent and the water is the solute. The solution is homogeneous. B. The copper compound is the solute and water is the solvent. The solution is homogeneous. C. The copper compound is the solvent and the water is the solute. The solution is heterogeneous. C. The copper compound is the solute and the water is the solvent. The solution Is heterogeneous. 4. Some of the most common metals with the highest melting points include nickel and tungsten, which melt at very high temperatures. Nickel melts around 1,452°C while tungsten melts around 3,399°C. What property is being described? A. Extensive Property B. Intensive Property C. Chemical Property D. Physical Property 5. Which of the following ions belong to Group II? A. Al 3+, Ag+, Au+ B. Be2+ , Sr 2+ , Mg 2+ C. Na+, Li+, Cs+ D. Na+, Ca2+,, Fe2+ 6. What is the correct formula for the ions sulfite and potassium? A. K2SO3 B. (SO3)K2 C. K(SO4)2 D. K2SO4 7. How many electrons are present in 16Al 2+ ? A. 18 B. 16 C. 20 D. 32 8. How many oxygen atoms are contained in 100 g of citric acid? A. 2.19 x 1021 atoms B. 6.02 x 1023 atoms C. 2.19 x 1021 atoms D. 4.47 x 1019 atoms 9. A chemist needs to get a sample of pure ethanol from a container containing ethanol in aqueous solution. What is the best method to use to get pure ethanol from the mixture? A. Decantation, to separate liquids on the difference of density. B. Chromatography, to separate components based on solubility. C. Fractional distillation. Due to the difference in boiling points of the components. D. Filtration, due to the solid component of the mixture. 10. How many protons and neutrons are there in the isotope ? A. 19 protons, 21 neutrons B. 21 neutrons, 19 protonsC. 19 protons,19 neutrons D. 19 protons, 59 neutrons 11. C. 12. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidizing agent. In solid-state, it has a melting point with a melting point of -101 ºC and a boiling point of -34.7 ºC. Which of these statements tells the chemical properties of chlorine? A. It is a green gas at room temperature C. boiling point of -34.7 ºC, melting point -101 ºC B. extremely reactive, strong oxidizing agent D. all of the above 13. What is the molar mass of the compound, tetracarbon dioxide? A. 36 mol B. 93 mole C. 48 mol D. 58 mol 14. Which among the following has the greatest formula mass? (Ca=40, S=32, O=16, Cl=35, N=14 , P=31, Ag=108, Na=23) A. CaSO4 B. NaOH C. P2Cl6 D. AgNO3 15. N2O has significant medical uses, especially in surgery and dentistry, for its anesthetic and pain-reducing effects. Its colloquial name, "laughing gas", coined by Humphry Davy, is due to the euphoric effects upon inhaling it, a property that has led to its recreational use as a dissociative anesthetic. What is the name of this compound? A. Nitroxide B. dinitrogen oxide C. mononitrogen monoxide D. nitrogen oxide 16. The following compounds are used as a preservative due to their low pH and ability to inhibit the growth of harmful bacteria that make food rot. A. Baking Powder B. Vinegar C. Table Salt D. Hydrochloric acid 17. What is the sum of the coefficients in a balanced uquation : Ca3(PO4)2 + SiO2 + C → CaSiO3 + CO + P A. 19 B. 18 C. 16 D. 14 18. What is the coefficient of H2SO4 in the reaction: 2__ Al(OH)3 + H2SO4 → Al2(SO4)3 + H2O A. 2 B. 3 C. 1 D. 6 19. What is the molar mass of the compound sodium acetate? (Na=23, C=12, O=16, H=1) A. 64 g/mol B. 94 g/mol C. 82 g/mol D. 66 g/mol D. 20. A sample of drain cleaner called “Liquid Sosa”, is a strong base that dissolves organic matter that might cause clogging of the sink. What is main ingredient of this cleaner? A. sodium hydroxide B. sodium chloride C. Ammonia D. hydrochloric acid 21. If you have 50 mg of sugar in a can of soft drink, how many molecules of sugar are present? A. 6.02 x 1025 molecules B. 3.13x1024 molecules C. 6.26x1020 molecules D. 6.26x1010 molecules 22. What is the balanced chemical equation given the reaction: ___Al(OH)3 + ___H2SO4 →___Al2(SO4)3 +___ H2O A. 3,2,2,6 B. 2,3,1,6 C. 2,1,2, 6 D. 2,3,2,6 23. What is the primary component of bleach, making it the most commonly used disinfectant at home? A. Hydrochloric acid, HCl C. Sodium Hypochlorite,NaClO B. Sodium hydroxide, NaOH D. Ammonium hydroxide , NH4OH 24. What is the molecular formula with an empirical formula of NH2, and a formula mass of 32.06 amu? ( n=14, O- 16) A. NH2 B. N2H4 C. N2H D. NH4 25. Which combination of chemical name and chemical formula below is correct? A. potassium nitrate, K2NO3 B. Hydrogen bromide H2Br C. sulfur trioxide SO3 D. carbon dioxide CO4 26. If you are to prepare spaghetti for merienda. The spaghetti stings are placed in hot water until it softens. What method of separation are you going to use in this situation? A. condensation B. distillation C. sieving D. evapation D. 27. A compound contains, by mass, 40.0% carbon, 6.71% hydrogen, and 53.3% oxygen. A 0.320 mole sample of this compound weighs 28.8 g. The molecular formula of this compound? A. C2H4O2 B. C3H6O3 C. C2H4O D. CH2O D. 28. Which among the following is an example of a ternary acid? A. nitrc acid B. hydrogen sulfate C. hydrofluoric acid D. hydrobromic acid 29. Guanidin, HNC(NH2)2, is a fertilizer. To three significant figures, what is the percent by mass of nitrogen in the fertilizer? A. 49.4% B. 54.8% C 65.1% D. 71.1% 30. Which among the following statements gives an exact number? A. Aliwagwag Falls in Davao Oriental, Mindanao heigh is 1110 meters. C. Weather conditions are at 40ºC. B. A swimmer finished the race in roughly 3 minutes. D. 5 students failed the test. 31. A carrot floats in salt water but sinks in fresh water. This is because _______. A. Salt water is more dense than freshwater C. Fresh water is more dense than salt water B. The carrot is more dense than salt water D. A larger piece of carrot has a different density 32. If two objects have the same volume but one has a greater mass, the one with greater mass _______. A. Has a lower density B. Has a higher density Cc. Will float D. Will sink 33. There are many uses of isotopes in the medical field. Which isotope is frequently used in cancer treatment due to its radioactive properties? A. Potassium-40 B.Cobalt-60 C. Calcium-45 D. Strontium-90 34. Chromatography is a process for separating components of a mixture. Where a dissolved substance is made to “run” into the chromatography paper as shown in the given figure on the right. What is the main principle involvein this technique? A. difference in electrical conductivity C. difference in melting points B. difference in densities of substances D. differences in solubility and adsorption 35. Copper exists as a mixture of two isotopes. Copper-63 is 69.17% abundant and it has a mass of 62.9296 amu. Copper-65 is 30.83% abundant and it has a mass of 64.9278 amu. Calculate the atomic mass of copper. A. 63.5556 amu B. 53.5645 amu C. 58.3452 amu D. 62.5566 amu 36. The molecular formula of a compound is C6H12O6. What’s the empirical formula for this compound? A. C6H12O6 B. CHO C. C2H6O2 D. CH2O 37. In naming a binary molecular compound, the number of atoms of each element present in the molecule is indicated by ____. A. Roman numerals B. prefixes C. superscripts D. suffixes C. 38. In a laboratory activity, students were asked to measure the weight and volume of the objects. The measurements are given on the right side. Arrange the object in increasing density. A. 1, 2, 3 B. 3, 2, 1 C. 3, 1, 2 D. 2.3, 1 39. Which of the following cannot be a molecular formula for an empirical formula HO? A. H2O B. H2O2 C. HO D. HO2 40. An element aluminum belongs to Group IIIA, what is its valence electron? A. 3 B. 3+ C. 0 D. 2+ 41. What is the oxidation of carbon in the compound, CH2Cl2 ? A. 0 B. 4+ C. 2+ D. +6 42. What is the correct formula for barium chlorate? A. Ba(ClO) B. BaClO2 c.. Ba(ClO)2 D. BaCl2 43. A chemical formula can be expressed in several ways. Which formula provides a graphic representation of how the atoms are arranged in a molecular structure? A. empirical formula B. structural formula C. molecular formula D. chemical formula 44. The Maynilad water facility supplies us with potable water. There are several stages involved in this process. What is the common method used to remove solid particles from water before it is supplied for drinking? A. sieving B. Evaporation C. distillation D. Filtration 45. In which of the following does sulfur have an oxidation number of +7? A. HSO3 - B. SO3 C. H2SO4 D. H2S2O8 46. How many neutrons are there for the element 25X55? A. 25 B. 55 C. 30 D. 80 47. Which of the following household substances is most commonly used as a cleaning agent due to its basic pH? A. Mohr’s salt, (NH4)2SO4. Fe(SO4). 6H2O C. Baking soda, NaHCO₃ B. Milk of magnesia, Mg(OH)₂ D. Isopropyl alcohol, C3H8O 48. Some properties are the same in a substance no matter the amount of the substance. Which of the following properties does not change based on the amount of the substance? A. density B. mass C. volume D. weight 49. All matter has physical and chemical properties. These properties can be used to identify the type of matter. Which of these statements describes a chemical property? A. A particular substance evaporates at 30 °C. B. A 2-ft.-long metal bar has a mass of only 176 g. C. A certain heavy metal turns to a liquid at room temperature. D. A metal is added to a beaker of water, and the beaker explodes. 50.. What type of compound is CuSO4 ? A. monotomic ionic B. polyatomic ionic C. polyatomic covalent D. binary molecular