Pregunta 1
Pregunta
A piece of metal weighing 59.047 g was heated to 100ºC and then put into 100 mL of water (initially at 23.7ºC). The metal and water were allowed to an equilibrium temperature, determined to be 27.8ºC. Assuming no heat lost to the environment, calculate the specific heat of the metal. Specific Heat of water = 4.18J/gºC Density of water = 1.00g/mL
Respuesta
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0.623 J/gºC
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1.79 J/gºC
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0.402 J/gºC
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0.721 J/gºC
Pregunta 2
Pregunta
In an experiment, 700 mL of 0.5 M hydrochloride acid (HCl) is added to 600 mL of of 0.5 M sodium hydroxide (NaOH) solution. The acid and base neutralize each other according to the equation: HCl + NaOH --> NaCl + H2O
How many moles of acid and base were there originally?
Respuesta
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0.35 mole of HCl and 0.3 mole of NaOH
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0.08 mole of HCl and 0.18 mole of NaOH
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0.035 mole of HCl and 0.05 mole of NaOH
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0.05 mole of HCl and 0.03 mole of NaOH
Pregunta 3
Pregunta
A chemist wants to determine the enthalpy of neutralization for the following reaction: HCl (aq) + NaOH (aq) --> NaCl (aq) + H2O (l)
The chemist uses a coffee-cup calorimeter to neutralize completely 70.5 mL of 2.56 M HCl (aq) with 30.5 mL of 2.56 M NaOH (aq). The initial temperature of both solutions is 16.8ºC. After neutralization, the highest recorded temperature is 22.6ºC. Calculate the enthalpy of neutralization in kJ/mol of H2O.
Assume that the density of the solution is 1.00 g/mL and specific heat is 4.18 J/gºC
Respuesta
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-29.2 kJ/mol
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29.2 kJ/mol
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-31.4 kJ/mol
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31.4 kJ/mol
Pregunta 4
Pregunta
Use the periodic table to predict which element has the largest ionization energy.
Pregunta 5
Pregunta
Use the periodic table to predict which element has the largest atomic radius.
Pregunta 6
Pregunta
Which of the following is a transition element?
Pregunta 7
Pregunta
The element germanium (Ge) is used in the manufacture of some transistors. What other element might be used for such a purpose?
Pregunta 8
Pregunta
When the excess of calcium carbonate is added to dilute HCl, the reaction gradually becomes slower and finally stops. Which statement best explains why this happens?
Respuesta
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An insoluble layer of calcium chloride is formed on the calcium carbonate.
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The concentration of HCl gradually reduces to zero.
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The pieces of calcium carbonate gradually become smaller.
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The calcium carbonate is covered by bubbles of carbon dioxide.
Pregunta 9
Pregunta
The molar volume of a gas-
Respuesta
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is commonly used in calculations as 22.4 L/mol at STP
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of 22.4 L/mol at STP is considered to be absolutely true only for ideal gases
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will change if the temperature and/or pressure change
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All of the above are true
Pregunta 10
Pregunta
In the reaction CH4 (g) + 2O2 (g) --> CO2 (g) + 2H2O (g)
18 L of oxygen would produce how many L of CO2 at STP?
(Hint: You must first balance the equation.)
Pregunta 11
Pregunta
A metal was found to release -1246 J of energy in a calorimeter. Initial temperature was 40.0ºC and the final temperature was 2.00ºC. The specific heat of the metal is 3.14 J/gºC, what is the mass of the metal used?
Respuesta
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4.40 g
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16.5 g
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9.44 g
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10.4 g
Pregunta 12
Pregunta
What is the mass in grams of 17.0 liters of methane gas (CH4) at STP?
MM of CH4 = 16.04 g/mol
Respuesta
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0.0473 g
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23.7 g
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6100 g
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12.2 g
Pregunta 13
Pregunta
During a Carbonate Analysis experiment, a 0.306 g sample of a CaCO3 "mixture" was used to collect 0.061 g CO2. Determine the mass of CaCo3 in the original mixture.
CaCO3 (g) + 2H3O+ (aq) --> Ca2+ (aq) + 2H2O (l) + CO2 (g)
MM of CaCO3 = 100.09 g/mol
MM of Co2 = 44.01 g/mol
Respuesta
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43.8 %
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75.6%
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45.4 %
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78.4 %
Pregunta 14
Pregunta
A 3 M HCl solution was used to generate the CO2 from the CaCO3 mixture. What would be the effect on the calculations if 6 M HCl was substituted for the 3 M HCl?
Respuesta
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no affect as long as the 3 M HCl is in access
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calculations would be too low
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calculations would be too high
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calculations can not be completed
Pregunta 15
Pregunta
Electrons are lost by the-
Respuesta
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reducing agent as it undergoes oxidation
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reducing agent as it undergoes reduction
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oxidizing agent as it undergoes oxidation
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oxidizing agent as it undergoes reduction
Pregunta 16
Pregunta
Phenolphthalein is ______ in basic solutions but _____ in acidic solutions.
Respuesta
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pink; colorless
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blue; colorless
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colorless; blue
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colorless; pink
Pregunta 17
Pregunta
In a titration, 34.12 mL of HCl required 42.03 mL of a 0.9981 M NaOH solution to reach the endpoint. Calculate moles of NaOH dispensed.
Respuesta
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0.03406 mol
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1.229 mol
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0.04195 mol
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41.95 mol
Pregunta 18
Pregunta
What is the difference between the endpoint and stoichiometric point in a strong acid/base titration?
Respuesta
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The endpoint is when the pH is exactly 7
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The stoichiometric point is when the pH is exactly 7
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The endpoint and the equivalence point are the same thing
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None of these answers are correct
Pregunta 19
Pregunta
At 16.7 mL volume of a 0.0861 M NaOH solution neutralizes 20.0 mL of HCl acid. What is the molar concentration of the HCl solution?
Respuesta
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0.0710 M
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0.0625 M
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0.0725 M
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0.0719 M