SAMPLE CHEMISTRY PLACEMENT EXAM QUESTIONS WITH COMPLETE SOLUTIONS 100% 2023/2024

SAMPLE CHEMISTRY PLACEMENT EXAM QUESTIONS WITH COMPLETE SOLUTIONS 100% 2023/2024 Answer: Oxygen Aluminum forms a +3 ion. In order for the formula unit Al₂X₃ to be electrically neutral, the element X must form a -2 ion. Nonmetals in the oxygen column do this. Of these elements, only oxygen is a diatomic gas. Aluminum reacts with element X to form a compound with the formula A₂X₃. Element X exists as diatomic molecules, X₂, in the gaseous state at normal temperature and pressure. Element X must be? Answer: 5 The balanced equation is 2 C₂H₄O + 5 O₂ → 4 CO₂ + 4 H₂O What is the coefficient of O₂ when the following equation is balanced? C₂H₄O + O₂ → CO₂ + H₂O Answer: 2.00 8.00 mol GeF₃H ( 1 mol GeH₄/ 4 mol GeF₃H) = 2.00 mol GeH₄ How many moles of GeH₄ are needed to form 8.00 moles of GeF₃H according to the following reaction? GeH₄ + GeF₄ → 4 GeF₃H Answer: A nonmetal Nonmetals are toward the upper right of the periodic table. All the elements in the fluorine column are nonmetals. According to its location in the periodic table, the element bromine (element # 35) is best described as Answer: NaCl HCl, hydrochloric acid, is a strong acid. NH₃, ammonia, is a weak base. In a solution of NaHCO₃, sodium hydrogen carbonate (baking soda), the hydrogen carbonate ion, HCO₃- , acts as a base. Neither the sodium ion Na+, nor the chloride ion, Cl - , which form when NaCl is dissolved in water, has significant acidic or basic properties. Which of the following species is neither acidic nor basic when dissolved in water Answer: 8.3 x 10⁸ The "calculator answer" is 8.2695.... x 10⁸. When the numbers in the numerator are subtracted the result, 8.53, must be rounded to one decimal place, or 8.5. Since this number has two significant figures, the result when it is divided by a number with 5 significant figures is limited to two significant figures. To the correct number of significant figures, the result of the following calculation [(11.13 - 2.6) x 10⁴]/[103.15 x 10− ⁶] should be reported as Answer: 14 How many total atoms are in the formula Al₂(CO₃)₃? Answer: 36 How many electrons are in Br-? Answer: 2, 3, 6, 1 What are the coefficients for the following reaction when it is properly balanced? Na₃PO₄ + Ba(NO₃)₂ → NaNO₃ + Ba₃(PO₄)₂ A) 3.00 mol Given that 4 NH₃ + 5 O₂→ 4 NO + 6 H₂O, when 4.50 mol of H₂O are formed, the amount of NO formed is A) 3.00 mol B) 6.75 mol C) 1.50 mol D) 4.50 mol acid-base neutralization What type of a reaction occurs when a sodium hydroxide solution is mixed with an acetic acid solution? Answer: A) Ne Which of the following atoms has the smallest radius? A) Ne B) O C) Li D) B Answer: Bent What is the molecular geometry if you have a double bond, a single bond and 1 lone pair around the central atom? D) 21.9 mL What volume of 12.0 M HCl is required to make 75.0 mL of 3.50 M HCl? A) 0.560 mL B) 257 mL C) 560. mL D) 21.9 mL D) 1.12 × 10² (2.80x10-³) (1.28 x 10¹)/(3.20 x 10-⁴)= A) 1.27 × 10¹ B) 2.0 × 10² C) 1.2 × 10⁶ D) 1.12 × 10² Answer: D) AsH₃ Of the molecules below, only __________ is polar. A) CH₄ B) SbF₅ C) CO₂ D) AsH₃ B) Ge Which one of the following is a metalloid? A) S B) Ge C) C D) Pb D) 18 A certain atom has a charge of -2 and has 16 protons and 16 neutrons in the nucleus. How many electrons does this atom possess? A) 34 B) 14 C) 32 D) 18 C) 0.0396 How many moles of pyridine (C₅H₅N) are contained in 3.13 g of pyridine? A) 0.00404 B) 25.3 C) 0.0396 D) 0.319 B) c + b/2 Solve the following equation for x: 4x - b = 2x + c A) c - b - 6 B) c + b/2 C) c + b/6 D) c - b/2 d) 0.7881. m3 Calculate the number of cubic meters of water in a fish tank holding 1.029 cubic yards of water. Hint, 1 meter = 1.093 yards. a) 1.062 m³ b) 0.9414 m³ c) 1.125 m³ d) 0.7881. m³ c) 133.0 °F The boiling point of acetone is 56.1 °C. What is this temperature on the Fahrenheit scale? Hint, x°F = 9/5 y°C + 32 a) 63.2 °F b) 149.2 °F c) 133.0 °F d) 48.9 °F b) 13 Looking at a Periodic table, determine the atomic number of Aluminum. a) 26.98 b) 13 c) 18 d) 39.95 (g) = gaseous state What does (g) represent in this equation for burning heptane, C₇H₁₆? C₇H₁ 6(1) + 11 0₂(g) → 7 CO₂(g) + 8 H₂O(I) 0.584 mol How many moles of CO2 will be produced when 8.34 grams of heptane, C₇H₁₆ are burned?