test Chemistry Questions /////////////

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Question Description

I don’t know how to handle this Chemistry question and need guidance.

 

The following electron-dot formulas for carbon dioxide both satisfy the octet rule for all of the atoms. Which of these structures is the better structure and why is this the case?

(a) “A” is the better structure because there is no formal charge on any of the atoms.
(b) “A” is the better structure because all the bonds and non-bonding electron pairs are arranged in a symmetrical pattern.
(c) “B” is the better structure because there are opposite formal charges on the two oxygen atoms which attract each other and give the molecule a lower energy.
(d) “B” is the better structure because the bond energies of a single bond and a triple bond are higher than the bond energies of two double bonds.
12. Which of the following gases would be most soluble in water?
(a) N2
(b) NH3
(c) CH4
(d) CO2
13. Which of the following compounds should have the highest boiling point?
(a) NH3
(b) CH4
(c) H2O
(d) HF

 

 How many moles of CO2 are present in 220 mg?
(a) 5 moles
(b) 0.005 mole
(c) 5000 moles
(d) 10 moles
2. What is the percent water in hydrated calcium chloride…CaCl2?2H2O?
(a) 66.67%
(b) 32.47%
(c) 24.51%
(d) 12.26%
3. What is the empirical formula for a compound that contains 17.34% hydrogen and 82.66% carbon?
(a) C5H
(b) C2H5
(c) CH3
(d) CH2
4. What is the molecular formula for a compound that is 46.16% carbon, 5.16% hydrogen and 48.68% fluorine if the molar mass of this compound is 156.12 g?
(a) C3H4F2
(b) C5H10F5
(c) C6H8F4
(d) C6H6F3
5. If 2.68 g of hydrated sodium sulfate, Na2SO4?nH2O, on heating produces 1.26 g of water, what is the empirical formula of this compound?
(a) Na2SO4?H2O
(b) 2Na2SO4?H2O
(c) Na2SO4?7H2O
(d) 9Na2SO4?8H2O
6. One mole of (NH4)2HPO4 contains _?_ moles of hydrogen atoms.
(a) 1
(b) 5
(c) 6
(d) 9

 

 If the temperature of a reaction is increased by 20oC, the reaction rate will be…
(a) 2 times as fast.
(b) 4 times as fast.
(c) 20 times as fast.
(d) unchanged because the reaction rate is not dependent on the temperature.
2. The following reaction coordinate diagram represents…
(a) an endothermic reaction.
(b) an exothermic reaction.
(c) a reaction that is neither endothermic nor exothermic.
(d) a reaction in which a catalyst is used.
3. When the following reaction equation is properly balanced, the number of moles of O2 will be…
(a) 1.5 moles
(b) 3.5 moles
(c) 3 moles
(d) 5 moles
4. When the following reaction equation is properly balanced, the number of moles of O2 will be…
(a) 1.5 moles
(b) 13 moles
(c) 19 moles
(d) 38 moles
5. Which of the following correctly represents the balanced chemical reaction between aluminum and sulfur?
6. An equilibrium constant of 10-4 for a reaction means that the reaction is…
(a) one that will have 50% product and 50% reactant at equilibrium.
(b) one that is very favorable and will have mostly product at equilibrium.
(c) one that is unfavorable and will not have very much product at equilibrium.
(d) The equilibrium constant only relates to the speed of a reaction and not to the amount of product formed.
7. Which of the following equations represents the equilibrium equation for the following reaction?
8. If additional calcium phosphate is added to the above reaction mixture, what will happen to the overall reaction?
(a) There will be no change in the overall reaction.
(b) The reaction will occur at a faster rate.
(c) Less of the reactants will react in order to compensate for the increase in the amount of one of the products of the reaction.
(d) More of the reactants will have to react in order to compensate for the increase in the amount of one of the products of the reaction.
9. In a single replacement reaction, why will one metal replace another metal in an ionic compound?
(a) The metal will replace another metal if it has a smaller mass and thus is able to hit the ionic compound with a higher velocity and thus more energy.
(b) The metal will replace another metal if it has a larger mass and thus is able to hit the ionic compound with more energy.
(c) The metal will replace another metal if it can gain electrons more readily than the other metal.
(d) The metal will replace another metal if it can lose electrons more readily than the other metal.
10. When two ionic compounds are dissolved in water, a double replacement reaction can…
(a) never occur since all ions in water are “spectator ions”.
(b) occur if two of the ions form an insoluble ionic compound, which precipitates out of solution.
(c) occur if the ions react to form a gas, which bubbles out of the solution.
(d) occur only if the ions form covalent bonds with each other.
11. The pH of a 1 molar solution of a weak acid with a Ka = 10-10 will be…
(a) 2.5
(b) 5
(c) 10
(d) Yikes! This question is lowering the pH of my stomach.
12. What is the oxidation number of chromium in the ionic compound Na2Cr2O7?
(a) 2
(b) 6
(c) 7
(d) 12
13. Which Br?nsted acid (H2O or H2S (aq)) is the stronger acid and why is it the stronger acid?
(a) H2O is the stronger acid because oxygen has a greater electronegativity than sulfur, which gives the attached hydrogen atom more proton character.
(b) H2O is the stronger acid because H2S is a gas and gases are not acids.
(c) H2S is the stronger acid because the hydrogen-sulfur bond is much weaker than the hydrogen-oxygen bond due to a greater difference in atomic orbital energy levels.
(d) H2S is the stronger acid because it is a heavier molecule and therefore has more energetic collisions.
14. Which Br?nsted acid (HCl (aq) or H2S (aq)) is the stronger acid and why is it the stronger acid?
(a) HCl is the stronger acid because it is a better proton donor.
(b) HCl is the stronger acid because the hydrogen-chlorine bond is much weaker than the hydrogen-sulfur bond due to a greater difference in atomic orbital energy levels.
(c) HCl is the stronger acid because chlorine has a greater electronegativity than sulfur, which gives the attached hydrogen atom more proton character.
(d) H2S is twice as strong an acid as HCl because it has two acidic hydrogen atoms versus only one hydrogen atom in HCl.
15. What is the oxidation number of nitrogen in the molecule N2?
(a) 0
(b) 3
(c) 5
(d) 7
16. Which of the following compounds is the strongest Br?nsted acid?
(a) H2SO4
(b) CH3CO2H
(c) HNO3
(d) H3PO4
17. Which of the following compounds is the strongest Br?nsted base?
(a) NaHSO4
(b) NaCH3CO2
(c) NaNO3
(d) NaH2PO4
18. Which of the following compounds is the strongest Br?nsted base?
(a) NaCH3
(b) NaOH
(c) NaF
(d) NaNH2
19. Which of the following compounds is the strongest Br?nsted acid?
(a) NH3
(b) HF
(c) H2O
(d) CH4
20. Which of the following chemical equations correctly represents the reaction between aluminum and oxygen?
21. Which of the following chemical equations correctly represents the reaction between calcium hydroxide and hydrochloric acid?
22. In the following reaction, the element that is oxidized is _?_ and the element that is the oxidizing agent is _?_.
(a) zinc…zinc
(b) bromine…bromine
(c) zinc…bromine
(d) bromine…zinc
23. Which of the following chemical equations correctly represents the reaction between sodium carbonate and phosphoric acid?
24. Which of the following compounds is the strongest Br?nsted acid?
(a) HCl
(b) HBr
(c) H2O
(d) H2S
25. Potassium bromate, KBrO3, is an additive to some flour (brominated flour) used to improve texture in the dough. It is a suspected carcinogen and some consumer groups want to ban this additive. The industry says that this compound is decomposed to KBr and O2 when the bread is baked and is thus not a risk to the health of the consumer…hmmm. When this reaction is balanced, the sum of the coefficients for the KBrO3 and KBr and O2 will be…

Can you think of an easy experiment to test the response made by industry?…answer (d).
(a) 3.5
(b) 5
(c) 7
(d) experiment
26. An iron nail was immersed in a solution of copper sulfate and when it was removed from the solution, it was coated with a layer of copper metal. After a different iron nail was immersed in a solution of zinc nitrate and removed, this nail rusted just as rapidly as a new iron nail. Rank these three metals in order of activity from most active to least active.
(a) Zn > Cu > Fe
(b) Fe > Cu > Zn
(c) Zn > Fe > Cu
(d) Cu > Fe > Zn
27. What is the balanced net ionic equation for the reaction of CaCl2 and AgNO3?
28. The “conjugate acid” in the reaction of H2SO4 with NaOH is…
(a) H2SO4
(b) NaOH
(c) Na2SO4
(d) H2O

 

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