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Chemistry Questions With Correct Answers

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Chemistry Questions With Correct Answers1. Carbon-12 and carbon-14 are isotopes. What do they have in common? A. Number of nuclear particles B. Number of protons C. Number of neutrons D. Mass numb... er - Correct Answer- B. Number of protons 2. A substance with a pH of 3 is how many times more acidic than a substance with a pH of 5? A. 8 B. 2 C. 100 D. 1,000 - Correct Answer- C. 100 The pH scale is a logarithmic scale. Therefore each number on the pH represents a tenfold increase or decrease in acidity. In this example, a difference in pH of 2 equals a 10 times 10, or 100 times increase in acidity; 10 x 10 = 100 3. Radioactive isotopes are frequently used in medicine. What kind of half-life would a medical isotope probably have? A. Seconds long B. Days long C. Year long D. Many years long - Correct Answer- B. Days long 4. When an acid is added to a base, water and a salt form. What kinds of bonds form in these two compounds? A. Liquid and metallic B. Polar and nonpolar covalent C. Polar covalent and ionic D. Ionic only - Correct Answer- C. Polar covalent and ionic 5. Al(NO3)3 + H2SO4 → Al2(SO4)3 + HNO3 is an example of which kind of reaction? A. Decomposition reaction B. Synthesis reaction C. Single replacement reaction D. Double replacement reaction - Correct Answer- D. Double replacement reaction 6. B, Si, As, Te, At, Ge, and Sb form a staircase pattern on the right side of the periodic table. How can these elements be classified? A+ A. As metals B. As semimetals C. As nonmetals D. As ultrametals - Correct Answer- B. As semimetals (Metalloids) 7. If gas A has four times the molar mass of gas B, you would expect it to diffuse through a plug ___________. A. at half the rate of gas B B. at twice the rate of gas B C. at a quarter the rate of gas B D. at four times the rate of gas B - Correct Answer- A. at half the rate of gas B M1 = 1 M2 = 4 4/1 = 2/1 (half) 8. Which of the following is not an allotrope of carbon? A. Diamonds B. Graphite C. Fluorine D. Buckminsterfullerene - Correct Answer- C. Fluorine (atomic element) 9. Which of these factors would not affect rates of reaction? A. Temperature B. Surface area C. Pressure D. Time - Correct Answer- D. Time 10. You would expect an amino acid to contain which two functional groups? A. R-NH2 and R-COOH B. R-CHO and R-CO-NH2 C. R-OH and R-COOR D. R-O-R and R-COOH - Correct Answer- A. R-NH2 and R-COOH 11. What is the coefficient of O2 after the following equation is balanced? A. 1 B. 2 C. 3 D. 4 - Correct Answer- B. 2 Examination of the first substance shows that methane gas has one carbon atom. There is also one carbon atom on the right side of the equation, so there is no need to balance this. There are four hydrogen atoms on the left side. To balance this, A+ change the coefficient on the right side so that there are four hydrogen atoms there as well: ___CH4 + ____O2 ---> ____CO2 + ____H2O Now there are two atoms of oxygen on the left and four on the right (two from carbon dioxide and two from water). To balance, change the coefficient on the left to 2: 1CH4 + 2O2 ---> 1CO2 + 2H2O 12. Which element would you e [Show More]

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