. 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. C. Na.
B. Sn. D. N.
4. According to Table 1 and the other information in your study unit, which of the following
elements is stable?
A. Neon C. Boron
B. Carbon D. Fluorine
5. The primary metallic element that’s added to steel to make stainless steel is
A. antimony.C. tungsten.
B. silver.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.C. alkali metal.
B. metalloid.D. halogen.
11. The molecular mass of sodium oxide (Na2O) is
A. 22.98977. C. 45.97954.
B. 38.98917. D. 61.97894.
12. Which of the following is represented in the highest percentage by volume in dry air?
A. Oxygen C. Carbon dioxide
B. Nitrogen 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.C. solution.
B. suspension.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. C. ClAl3.
B. AlCl3. D. Cl3Al.
19. An atom of chlorine has several valence electrons in its
A. nucleus.C. second shell.
B. first shell. D. third shell.
20. The names of the compounds FeS, NaCl, NaOH, and Pb(CN)2 all end in the suffix
A. -ide.C. -ic.
B. -ite.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 C. CO2 + C2 →CO
B. CO2 + C →2CO D. CO2 + C →C2O
23. One atom of silicon can properly be combined in a compound with
A. one atom of chlorine. C. three atoms of hydrogen.
B. two atoms of oxygen. D. four atoms of calcium.
24. Which one of the following formulas represents an aldehyde?
A. C6H10O5 C. C2H5OH
B. C2H4O 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.C. nuclear fusion.
B. artificial disintegration.D. nuclear fission.
I'm not about to take the time to answer 24 questions; however, I WILL check your answers if you post them two or three at a time AND TELL US WHAT YOU THINK AND WHY.
7 is c
1. To determine which of the following options will result in a chemical change, we need to understand what a chemical change is. A chemical change occurs when the substances involved react with one another to form new substances with different properties.
A. Melting ice to obtain water: Melting ice is a physical change because it involves a change in state from solid to liquid, but the identity of the substance (water) remains the same. So, this is not a chemical change.
B. Evaporating alcohol into vapor: Evaporating alcohol is also a physical change because it involves a change in state from liquid to gas, but the identity of the substance (alcohol) remains the same. So, this is not a chemical change.
C. Drying wood in a shed: Drying wood is a physical change because it involves the removal of moisture from the wood, but the identity of the substance (wood) remains the same. So, this is not a chemical change.
D. Burning coal in a furnace: Burning coal is a chemical change because it involves a reaction between coal and oxygen in the air, resulting in the formation of new substances (such as carbon dioxide and ash) with different properties. So, this is the option that will result in a chemical change.
Therefore, the correct answer is D. Burning coal in a furnace.
2. To determine which of the following is a reaction between a salt, we need to understand what a salt is and how it is formed. A salt is a compound formed by the reaction between an acid and a base, where the hydrogen ions from the acid are replaced by metallic or ammonium ions from the base.
A. A nonmetal and a metal: This is not the correct combination for forming a salt.
B. A base and water: This is also not the correct combination for forming a salt. When a base reacts with water, it forms hydroxide ions, but not a salt.
C. An acid and oxygen: This is not the correct combination for forming a salt. The reaction between an acid and oxygen typically results in the formation of oxides, not salts.
D. A base and an acid: This is the correct combination for forming a salt. When a base reacts with an acid, it forms a salt and water.
Therefore, the correct answer is D. A base and an acid.
3. To determine the chemical symbol for sodium, we need to refer to the periodic table. The chemical symbol is a one- or two-letter abbreviation used to represent an element.
A. S is the chemical symbol for sulfur, not sodium.
B. Sn is the chemical symbol for tin, not sodium.
C. Na is the correct chemical symbol for sodium.
D. N is the chemical symbol for nitrogen, not sodium.
Therefore, the correct answer is C. Na.
4. To determine which element is stable, we need to refer to Table 1 and consider the information provided in the study unit. Stability in this context typically refers to the lack of reactivity or tendency to undergo chemical reactions.
A. Neon is a stable element because it is a noble gas and generally does not react with other elements.
B. Carbon is a nonmetal and can form stable compounds, but it is not as stable as neon.
C. Boron is a metalloid and can form stable compounds, but it is not as stable as neon.
D. Fluorine is a highly reactive element and is not considered stable.
Therefore, the correct answer is A. Neon.
5. To determine the primary metallic element added to steel to make stainless steel, we need to understand the properties and composition of stainless steel.
A. Antimony is not typically added to steel to make stainless steel.
B. Silver is not typically added to steel to make stainless steel.
C. Tungsten is not typically added to steel to make stainless steel.
D. Chromium is the primary metallic element added to steel to make stainless steel, as it provides corrosion resistance and enhances the steel's ability to form a protective oxide layer.
Therefore, the correct answer is D. Chromium.
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