Science help?

Which of the following will result in a chemical change?





A. Melting ice to obtain water


B. Evaporating alcohol into vapor





C. Drying wood in a shed





D. Burning coal in a furnace














2. A salt is obtained as a reaction between





A. a nonmetal and a metal.


B. a base and water.





C. an acid and oxygen.





D. a base and an acid.














3. The chemical symbol for sodium is





A. S.


B. Sn.





C. Na.





D. N.














4. According to Table 1 and the other information in your study unit, which of the following elements is stable?





A. Neon


B. Carbon





C. Boron





D. Fluorine














5. The primary metallic element that's added to steel to make stainless steel is





A. antimony.


B. silver.





C. tungsten.





D. chromium.














6. The atomic number of oxygen is 8, because oxygen has





A. eight protons in the nucleus.


B. electrons in eight shells.





C. a second shell with eight electrons.





D. an atomic mass of 8.














7. Which one of the following chemical equations is balanced?





A. 2NaCl + H2SO4 → HCL + NaSO4


B. NH3 + H2O → 2NH4OH





C. KOH + H2SO4 → KHSO4 + H2O





D. 2Na + S → 2NaS














8. Which of the following is one way to prevent the corrosion of iron?





A. Protect the iron from polluted air.


B. Add carbon to the iron.





C. Let the iron develop a natural coat of carbonate.





D. Paint exposed iron parts with protective paint.














9. Which one of the following groups of chemical compounds is composed entirely of organic compounds?





A. C2H4O, CH2O, CaSO4, C3H5(OH)3


B. C6H6, C2H5OH, C6H5CH3, C3H5(NO3)3





C. C2H2, CH4, CaCl2, CaCN2





D. Ch3OCH3, Ca3(PO4)2, CO2, H2CO3














10. According to the periodic table in your study unit, the element fluorine is classified as a





A. metal.


B. metalloid.





C. alkali metal.





D. halogen.














11. The molecular mass of sodium oxide (Na2O) is





A. 22.98977.


B. 38.98917.





C. 45.97954.





D. 61.97894.














12. Which of the following is represented in the highest percentage by volume in dry air?





A. Oxygen


B. Nitrogen





C. Carbon dioxide





D. Hydrogen














13. Sodium is preferred over potassium in industrial applications because





A. sodium salts are easily decomposed.


B. sodium is produced more economically.





C. potassium oxidizes more slowly in air.





D. potassium has a higher melting temperature.














14. In the process of electrolysis, current can flow through a liquid because





A. cations of the electrolyte accumulate at the positive electrodes.


B. hydrogen is electrically neutralized in the solution.





C. water molecules become negatively charged.





D. negative ions are attracted to the anode.














15. In the chemical equation Zn + 2HCL → ZnCl2 + H2, the reactants are





A. zinc chloride and hydrogen.


B. zinc and hydrogen carbonate.





C. zinc chlorate and water.





D. zinc and hydrochloric acid.














16. If water and oil are combined in a container, the resulting liquid is a(n)





A. emulsion.


B. suspension.





C. solution.





D. mixture.














17. Which one of the following statements about sulfuric acid is correct?





A. Sulfuric acid is a known muriatic acid.


B. Sulfuric acid is a strong oxidizing agent.





C. Sulfuric acid has little effect on metals.





D. Sulfuric acid is dangerous to living organisms.














18. The valence of aluminum is +3, and the valence of chlorine is -1. The formula for aluminum chloride is correctly written as





A. Al3Cl.


B. AlCl3.





C. ClAl3.





D. Cl3Al.














19. An atom of chlorine has several valence electrons in its





A. nucleus.


B. first shell.





C. second shell.





D. third shell.














20. The names of the compounds FeS, NaCl, NaOH, and Pb(CN)2 all end in the suffix





A. -ide.


B. -ite.





C. -ic.





D. -ate.














21. Which one of the following is a characteristic of a metal?





A. Conducts heat readily


B. Changes the color of litmus paper to red





C. Reacts with bases to produce salts





D. Becomes negative when combined with other elements














22. Examine the following unbalanced chemical equation: CO2 + C → CO. Which of the following is the correctly balanced form of this equation?





A. 2CO2 + C → CO


B. CO2 + C → 2CO





C. CO2 + C2 → CO





D. CO2 + C → C2O














23. One atom of silicon can properly be combined in a compound with





A. one atom of chlorine.


B. two atoms of oxygen.





C. three atoms of hydrogen.





D. four atoms of calcium.














24. Which one of the following formulas represents an aldehyde?





A. C6H10O5


B. C2H4O





C. C2H5OH





D. CH3COOH














25. In a nuclear reaction, energy is released by the combination of two elements into a new element. This process is an example of





A. natural radioactivity.


B. artificial disintegration.





C. nuclear fusion.





D. nuclear fission.

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