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First Semester Chemistry FAQs

Get answers to common chemistry questions from the first semester. Explore topics such as chemical reactions, bonding, stoichiometry, and more in an easy-to-understand format.

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First Semester Chemistry FAQs

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  1. First Semester Chemistry!

  2. Question 1 - 10 What is the name for HNO3?

  3. Answer 1 – 10 Nitric Acid

  4. Question 1 - 20 What type of bond represents a sea of electrons?

  5. Answer 1 – 20 • Metallic Bonding

  6. Question 1 - 30 The electrons in a nonpolar covalent bond are: • Unequally shared between atoms • Just exist and do not interact • Shared equally between atoms

  7. Answer 1 – 30 C) Shared equally between atoms

  8. Question 1 - 40 Balance this equation: __ HF(aq)+__Ca(OH)2(aq) → __ H2O(aq)+__ CaF2 (aq)

  9. Answer 1 – 40 2 HF(aq)+Ca(OH)2(aq) → 2 H2O(aq)+ CaF2 (aq)

  10. Question 1 - 50 Name 6 polyatomic ions

  11. Answer 1 – 50 NH4+ NO2- NO3- SO32- OH-  CN-

  12. Question 2 - 10 • What are the products in this double displacement reaction? NaOH (aq) + MgCl2 (aq) → ?? 2. Does a precipitate form?

  13. Answer 2 – 10 • 2NaOH (aq) + MgCl2(aq) → 2NaCl  + Mg(OH)2 • Yes! Mg2+(aq) + 2OH-(aq) → Mg(OH)2(s)

  14. Question 2 - 20 What is a spectator ion?

  15. Answer 2 – 20 • its an ion that is present in solution but does not participate in the reaction

  16. Question 2 - 30 • What is the difference between a strong base and a strong acid?

  17. Answer 2 – 30 • Strong Acid completely dissociates into H+ and anion in water • Strong Base completely dissociates into OH- and cation in water

  18. Question 2 - 40 • Explain how to distinguish between the following types of reactions: • Single replacement • Double displacement (precipitation) • Synthesis • Acid-Base

  19. Answer 2 – 40 • Single Replacement: element a + compound BC → element B + compound AC • Double Displacement/precipitation: a solid forms after mixing solutions of 2 ionic compounds • Synthesis: 2 reactants → 1 Product • Acid-Base: form H2O from H+ and OH- ions

  20. Question 2 - 50 • How do you recognize the correct chemical formula for an ionic compound?

  21. Answer 2 – 50 • When the (+) cation(s) combine with the (-) anion(s) in a ratio that results in a net charge of 0

  22. Question 3 - 10 • How many zeros does Avogadro's Number have?

  23. Answer 3 – 10 • 24 zeros • 6.02 x 10-23

  24. Question 3 - 20 • What is the molar mass of CO2 expressed with 3 sig figs?

  25. Answer 3 – 20 • 44.0 g/mol • Carbon = 12.01 g/mol • Oxygen = 16.00 g/mol (2x) • Add all together = 44.01 g/mol • 3 sig figs!

  26. Question 3 - 30 • How many sig figs are in the measurement 0.003540 kg?

  27. Answer 3 – 30 • 4 sig figs

  28. Question 3 - 40 • If the reactants areNa₂S and Cu(NO₃)₂, what will the products be?

  29. Answer 3 – 40 • NaNO₃ and CuS

  30. Question 3 - 50 Determine the: • Empirical Formula • Molecular Formula • Percent Composition Of a substance with the molar mass of 78 g/ mol • Percent of C: 92.3 % • Percent of H: 7.7 %

  31. Answer 3 – 50

  32. Question 4 - 10 • Stoichiometry heavily relies on _____ ratios.

  33. Answer 4 – 10 • Mole

  34. Question 4 - 20 • A sample contains 27.1 g of calcium oxide.  How many moles of calcium oxide are in the sample?

  35. Answer 4 – 20 • 0.483 mol

  36. Question 4 - 30 • A 2.00 g sample of ammonia is mixed with 4.00 g of oxygen.  Which is the limiting reactant and how much excess reactant remains after the reaction has stopped? 4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(g)

  37. Answer 4 – 30 • Limiting Reactant: • Excess Reactant:

  38. Question 4 - 40 • Define limiting reactant and excess reactant.

  39. Answer 4 – 40 • Limiting Reactant - The reactant in a chemical reaction that limits the amount of product that can be formed.  The reaction will stop when all of the limiting reactant is consumed. • Excess Reactant - The reactant in a chemical reaction that remains when a reaction stops when the limiting reactant is completely consumed.  The excess reactant remains because there is nothing with which it can react.

  40. Question 4 - 50 • 90.0 g of FeCl3 reacts with 52.0 g of H2S.  What is the limiting reactant?  What is the mass of HCl produced?  What mass of excess reactant remains after the reaction?

  41. Answer 4 – 50 • Grams of HCL: 60.8 g • Limiting Reactant: FeCl3 • Excess reactant: 23.6 g H2S

  42. Question 5 - 10 • Is burning coal an exothermic or an endothermic reaction?

  43. Answer 5 – 10 • Exothermic; heat is leaving the system.

  44. Question 5 - 20 • A 450 g piece of iron (specific heat: 0.449 J/g°C ) is heated from 22°C to 87°C. How much heat was necessary to cause this change?

  45. Answer 5 – 20 • 13,000 J

  46. Question 5 - 30 • Which of the following is not a state function? Distance, energy, or temperature?

  47. Answer 5 – 30 • Distance

  48. Question 5 - 40 • How much energy is required to heat 7.40 mL of water from 25°C to 46°C?

  49. Answer 5 – 40 • q = mc delta T • q = (7.40 g) (4.184 J/gC) (21 C) • 7.40 mL X 1g/1mL = 7.40 g water • q = 650. J • 7.40 mL X 1g/1mL = 7.40 g water

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