Chemistry Past Paper PDF

C How will you illustrate the structure of an ethyl alcohol? a\. c.  b\. d.  D Which hydrocarbon compound has a triple bond in the molecule? a\. octane b. methane c. ethene d. ethyne C Which type of elements tend to gain electron/s during ionic bonding...

C How will you illustrate the structure of an ethyl alcohol? a\. c.  b\. d.  D Which hydrocarbon compound has a triple bond in the molecule? a\. octane b. methane c. ethene d. ethyne C Which type of elements tend to gain electron/s during ionic bonding? a\. metals c. non-metal b\. metalloid d. super-alloy A Why do atoms react with one another to form chemical bonds? a\. to attain stability c. to form molecules b\. to form compounds d. to produce ions D Why is mole concept important? a\. It is useful when converting between grams and atoms or molecules b\. It gives us a convenient way to express large numbers c\. It can be applied to any type of particle representative d\. All of the above. D What can you infer with the electron configuration 1s^2^ 2s^2^ 2p^5^ 3s^1^, for a neutral atom? a\. The atomic number is eight b\. The 1s and 2s orbitals are not filled c\. The atom is in the ground state and the atomic number is ten d\. The atom is in the excited state and the atomic number is ten. A/C Which of the following statement best describes organic compounds? a\. Organic compounds are composed mainly of carbon and hydrogen. b\. Organic compounds are compounds that contain carbon atoms only. d\. Organic compounds are compounds that contain carbon and oxygen only. C Most of the elements in the periodic table are metals. Metals can be distinguished from non-metals by differences in physical properties. Which row correctly describes a metal? Malleability Heat and electrical conductivity --- -------------- ---------------------------------- a x / b / x c / / d X x A It is the measure of the ease at which an electric charge or heat can pass through a material. a\. conductivity c. solubility b\. ductility d. boiling point C.Which of the following is not a true statement concerning the gram atomic mass? b\. The gram atomic mass is the mass of one mole of atoms. c\. The gram atomic mass is found by checking the periodic table. B How would you explain carbon such a unique element? b\. Carbon forms four bonds, although the ground state configuration would predict the formation of fewer bonds. A Who was the first scientist to propose a model for the structure of the atom? a\. DEMOCITUS c. Thomson b\. Bohr d. Schrodinger B How do carbon atoms form many organic compounds? a\. By attracting other elements toward themselves to form bond. b\. By sharing their electrons with other metal and non-metal elements. c\. By transferring their electrons to the atoms of surrounding elements d\. By forming mainly bonds with other carbon atoms and other elements. B What will most likely happen to a non-metallic atom after ionic bonding? I. It forms cation III. It becomes stable II\. It forms an anion IV. It becomes unstable a\. I and II b. II and III c. III and IV d. I and IV C What is the common use of ETHYNE? a\. Disinfectant c. artificial ripening agent b\. fertilizer d. fuel A The capability of a metal to be drawn into wire is known as a\. Ductility b. expandability c\. strength d. malleability C Why can metals be hammered without breaking? a\. They are ductile. c. They are malleable b\. They are not brittle. d. Their particles are strong. A If you saw the following, K+; how will you explain about the ion? a\. It has lost one electron b\. It has lost one proton c\. It has lost 2 electrons d\. It is a negative ion D How can the knowledge about mole be useful for environmentalists? a\. Mole concept can be used in environmental monitoring. b\. It gives information on the most dangerous pollutant in the atmosphere. c\. It gives feedback on the kinds of pollutants present in atmosphere. B Which of the properties of atoms is the most suitable reference for the kind of bond that will take place between/among them? a\. atomic size c. ionization energy b\. electronegativity d. electron affinity D Which are TRUE about organic compounds? I. Organic compounds contain calcium. II\. Organic compounds contain carbon III\. Organic compounds can be produced by living organisms. IV\. Organic compounds can be produced artificially. a\. I, II and III only C. II and III only b\. I and III only D. II, III and IV only. D On the basis of Rutherford's model of the atom, which subatomic particle is present in the nucleus of an atom? a\. proton and electron c. proton and neutron b\. neutron and electron d. proton only C Which hydrocarbon compound has a double bond in the molecule? a\. ethane b. methane c. propene d. propyne B Maria Paula wants to preserve a fish for her project in Biology class. What kind of compound should she use to preserve the animal? a\. acetic acid c. methyl alcohol b\. formaldehyde d. acetone B Choose the best description for the given pictures? a\. These materials are easily found at home b\. These materials are made up of carbon c\. These materials are hard d\. None of these C How would you write the correct electron configuration of Sc~21~? a\. 1s^1^ 2s^2^ 2p^3^ 3p^4^ 3d^10^ 4s^1^ c. 1s^2^ 2s^2^ 2p^6^ 3s^2^ 3p^6^ 4s^2^ 3d^1^ b\. 1s^2^ 2s^2^ 2p^6^ 3s^1^ 3p^6^ 4s^2^ 3d^6^ d. 1s^2^ 2s^1^ 2p^2^ 3s^2^ 3p^6^ 4s^2^ 3d^6^ D. How can you apply knowledge on percentage composition? a\. In maintaining the quality of the product b\. In checking the amount of sugar present in soft drinks c\. In identifying the current amount of substance present in a sample d\. all of the above B Which of the following gives the best explanation for why a substance does not conduct electricity? b\. The bonding model in the substance does not have free electrons c\. The bonding model does not have ions which are free to move, or free electrons. d\. None of them B Marcela told her grandson, Miguel, never play with gasoline. Why do you think she does not allow him to do it? a\. Because gasoline is volatile b\. Because gasoline is flammable. c\. Because gasoline is viscous d\. All of the above. C To which group of hydrocarbon does the molecule with the structure H-C=C-H belong? a\. alkane b. alkyne c. alkene d. none of the above A Which of the following materials found at home is a good conductor of electricity? a\. iron b. plastic c. wood d. glass B What will formed if there is a sharing of electrons among elements. a\. Ionic Bonding b. Covalent Bonding c. Metallic Bonding d. Family Bonding A It is ratio of the amount of each element to the total amount of individual elements present in the compound multiplied by 100. a\. Percentage composition b\. Molar mass c\. Formula units d\. Molecular formula B Compute for the percentage composition by mass of sulfur (atomic mass: 32) in the compound MgSO4 (gram formula mass = 120) a\. 20% b. 27% c. 46% d. 53% C Count the number of particles present in one mole of any kind of substance. a\. 3.01 x 10^23^ b. 3.01 x 10^24^ c. 6.02 x 10^23^ d. 6.02 x 10^24^ A Where in the diagram of the Periodic table will you find the most reactive metals? a\. 1 b. 4 c. 3 d. 2 A..When can you say that our environment becomes more dangerous in terms of mole? a\. The higher the number of moles b\. The lower the number of moles c\. The lower the pollutants d\. The more infrastructures For numbers 49-50, refer to the table below. Analyze then answer the questions that follow. +-------------+-------------+-------------+-------------+-------------+ | Name of | Chemical | Symbol of | Atomic | | | compound | formula | elements | Number | | +=============+=============+=============+=============+=============+ | Calcium | CaCO~3~ | Ca | Ca= 40g | 1 atom of | | Carbonate | | | | Ca | | | | C | C= 12g | | | | | | | 1 atom of C | | | | O | O=16g | | | | | | | 3 atoms of | | | | | | O | +-------------+-------------+-------------+-------------+-------------+ C. What will be the molar mass of calcium carbonate? a\. 80g/mol b. 68g/mol c. 100g/mol d. 71g/mol D. What will be the percentage composition of Oxygen in the sample? a\. 40% b. 12% c. 16% d. 48%