Question 4. Aqueous solutions of which of the following pairs of compounds will not
I. PART 1 (7.0 points) Question 1. The equation represents a chemical reaction at equilibrium
2HCl (aq) + Mg (s) MgCl2 (aq) + H2 (g) + heat
What happens to the system when the temperature is decreased?
A. The reaction shifts toward the right, and the amount of hydrogen gas increases.
B. The reaction shifts toward the right, and the amount of hydrogen gas decreases.
C. The reaction shifts toward the left, and the amount of hydrogen gas increases.
D. The reaction shifts toward the left, and the amount of hydrogen gas decreases.
Question 2. How does a single covalent bond between two carbon atoms compare to a double covalent bond between two carbon atoms?
A. single covalent bond is stronger and has a longer bond length than a double covalent bond.
B. A single covalent bond is stronger and has a shorter bond length than a double covalent bond.
C. A single covalent bond is weaker and has a shorter bond length than a double covalent bond
D. A single covalent bond is weaker and has a longer bond length than a double covalent bond
Question 3. Sulfur dioxide gas, SO2(g), in air contributes to the formation of acid rain.
The concentration of SO2(g) in air can be determined by dissolving the SO2(g) in water and then titrating the solution produced with a standard solution of potassium
permanganate, KMnO4(aq). The titration reaction can be represented by the following unbalanced equation.
SO2(aq) + MnO4–(aq) + H2O(l) → SO42–(aq) + Mn2+(aq) + H+(aq) a) During the titration, a student would expect to observe
A. an increase in acidity B. a decrease in solution volume
C. a decrease in the electrical conductivity D. an increase in the intensity of the purple colour
b) A 150 mL sample of SO2(aq) required 31.5 mL of 0.0100 mol/L KMnO4(aq) to completely react. The concentration of SO2(aq) in the sample was
A. 0.840 mmol/L B. 2.10 mmol/L C. 5.25 mmol/L D. 118 mmol/L Question 4. Which of the following molecules has a nonpolar covalent bond?
A. H–Br B. H–Cl C. H–F D. H–H Question 5. Magnesium metal reacts with iron(III) sulfate to produce iron metal and magnesium sulfate, as shown in the equation below. The molar mass of iron(III) sulfate is 399.9 g/mol.
3Mg + Fe2(SO4)3 3MgSO4 + 2Fe
How many grams of iron(III) sulfate are needed to completely react 6.0 g of magnesium?
A. 2.0 g B. 33 g C. 99 g D. 300 g
Question 6. The chemical equation below represents the reaction of 1 mol of hydrogen gas (H2) with 1 mol of chlorine gas (Cl2) in a sealed container at STP. The reaction produces 2 mol of hydrogen chloride gas (HCl) in the sealed container.
H2 + Cl2 2HCl
What is the pressure in the container at standard temperature after the reaction is complete?
A. 1 atm B. 2 atm C. 3 atm D. 4 atm
Question 7. The diagram below shows the relative locations of five unidentified elements in the periodic table: E, X, G, J, and L.
Element X has an atomic number of Z. Which unidentified element has an atomic number of Z + 2?
A. element E B. element G C. element J D. element L Question 8. A sample of vinegar has a pH of 5, and a sample of rainwater has a pH of 6.
Which of the following statements best describes these two substances?
A. Both samples are bases, and vinegar is more basic.
B. Both samples are acids, and vinegar is more acidic.
C. Both samples are bases, and rainwater is more basic.
D. Both samples are acids, and rainwater is more acidic.
Question 9. A student pours hydrochloric acid (HCl) into an open beaker that contains a piece of magnesium (Mg). A chemical reaction occurs, as shown in the equation below.
2HCl (aq) + Mg (s) MgCl2 ( aq) H2(g) The data for the reaction are shown in the table below.
Which of the following statements best explains why the total mass of the substances in the beaker before the reaction is different from the total mass after the reaction?
A. The HCl and Mg react slowly.
B. The hydrogen produced is a gas.
C. The HCl and Mg react to form a precipitate.
D. The magnesium chloride produced is soluble.
Question 10. What do the ions K+ , Ca2+ and Cl- have in common?
A. They have the same number of protons C. They will form covalent bonds with oxygen B. They have the same configuration as argon D. They have larger than their corresponding atoms
Question 11. In an experiment, 2.62 g of iron react completely with 1.50 g of sulfur.
What is the empirical formula for the compound produced?
A. FeS B. FeS2 C. Fe2S D. Fe2S3
Question 12. What type of chemical reaction is represented by this balanced equation?
A. Synthesis B. Decomposition C. Single replacement D. Double replacement
Question 13. Using the solubility graph provided, a student performs an experiment to find the solubility of a substance. The student finds the amount of substance needed to make a saturated solution in 100 g of water at different temperatures. The student‘s data are shown in the table below the graph.
What is the identify of substance?
A. Sodiun nitrate B. potassium nitrate C. sodium chloride D. potassium chlorate
Question 14. An equilibrium is established between substances W, X, Y, and Z.
W + X Y + Z
How would the conditions of equilibrium be affected by decreasing the concentration of substance W?
A. Substances X and Y would react to replace substance W, and the position of equilibrium would shift to the right.
B. Substances Y and Z would react to replace substance W, and the position of equilibrium would shift to the left.
C. This would increase pressure, causing only substance Y to replace substance W and shifting the equilibrium to the right.
D. This would decrease temperature, causing only substance Z to replace substance W and shifting the equilibrium to the left
Question 15. Which statement explains what happens when potassium chloride (KCl) dissolvesin water?
A. Water molecules surround the potassium chloride but do not exert forces of attraction strong enough to break any bonds.
B. Water molecules exert forces of attraction that break the potassium chloride apart into potassium ions and chloride ions.
C. Water molecules exert forces of attraction that break the potassium chloride apart into neutral atoms of potassium and neutral atoms of chlorine.
D. Water molecules exert forces of attraction that break the potassium chloride apart into potassium atoms and diatomic chlorine gas
Question 16. The diagram below shows the solubility of sugar in water
A student dissolves 300 g of sugar in 100 g of water at 80°C. The solution is then allowed to cool to 40°C. The appearance of the solution does not change during the cooling.
Which term accurately describes the solution at 40°C?
A. Suspension B. Colloid C. Supersaturated D. Unsaturated Question 17. What type of solution is formed when solid sodium hydroxide (NaOH) is dissolved in water?
A. An electrolytic solution, because NaOH will dissociate into ions B. An electrolytic solution, because NaOH will not dissociate into ions C. A nonelectrolytic solution, because NaOH will dissociate into ions D. A nonelectrolytic solution, because NaOH will not dissociate into ions
Question 18. The chemical equation below represents a reaction at equilibrium in a closed flask.
Which action will cause the reaction to shift to the left?
A. heating the flask with a hot plate B. placing the flask in an ice bath C. removing H2O from the flask D. adding CO to the flask
Question 19. How many O2 particles are in 2.50 moles of O2 at Standard Temperature and Pressure (STP)?
A. 4.15 × 1022 particles B. 2.41 × 1023 particles C. 5.02 × 1023 particles D. 1.51 × 1024 particles