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CHEN 1211 Midterm: chen1211_u_1

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turquoisegnu128
31 Jan 2019
School
CU-Boulder
Department
Chemical Engineering
Course
CHEN 1211
Professor
All

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Document Summary

When aluminum (al) reacts with phosphorus (p), the resulting compound has the formula: a. b. c. d. e. lpa lpa 2. 3 l pa 2: suppose that a fictitious element, x, has two isotopes: The lighter isotope has an abundance of 63. 7%. 24: which of the following statements about orbitals are true, no orbital can contain more than two electrons. ll. All orbitals have at least one node lll. Electrons in an orbital must be located within the surface of their orbital. lv. H: the number of electrons occupying all d orbitals in 1. 0g of kr is a. b. c. d. e. a. b. c. 24: what is the oxidation number of the sulfur atom in a. 4: the mixing of which pair of reactants will result in a precipitation reaction? a. b. c. d. e. 4 l icl, and ki are all classified as: acids, nonelectrolytes, strong electrolytes, weak electrolytes, both a and c, when calcium carbonate (

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Related Questions

Having trouble with thse questions. Please answer all questions correctly. Will provide a thumbs up.

1.Which of these equations is the balanced reaction between nitrous acid solution and solidmagnesium hydroxide ?

A.2NH3(aq) + MgOH (s) Mg(NH4)2(aq) + 2 H2O(l)

B.2HNO2(aq) + Mg(OH)2(s) Mg(NO2)2(aq) + 2 H2O(l)

C.2HNO3(aq) + Mg(OH)2(s) Mg(NO3)2(aq) + 2 H2O(l)

D.2HNO2(aq) + MgOH (s) Mg(NO3)2(s) + 2H2O(l)

2.Balance the following chemical equation:

C3H7OH(l) + O2(g)CO2(g) + H2O(g)

a. C3H7OH(l) + 4 O2(g)3 CO2(g) + 4 H2O(g)

b.2 C3H7OH(l) + 9 O2(g)6 CO2(g) + 8 H2O(g)

c.C3H7OH(l) + 5 O2(g)3 CO2(g) + 4 H2O(g)

d.C3H7OH(l) + O2(g)CO2(g) + H2O(g)

3.Which species would be considered a spectator ion based on the following equation?

Ba2+ + 2NO3− + 2Na+ + SO42- → BaSO4(s) + 2NO3− + 2Na+

SO42-

2NO3−

Ba2+

BaSO4

4.Barium sulfate is often ingested to aid in the diagnosis of GI tract disorders. The equation for its production is Ba2+ + SO42- → BaSO4(s). What type of equation is this?

A full equation

A net ionic equation

A total ionic equation

An oxidation-reduction equation

5.Which species is being reduced in this reaction?

CuO(s) + H2(g) Cu(s) + H2O(g)

H2O

CuO

Cu

H2

6.Which of the following is an oxidizing agent?

H2

NH3

O2

H2O

7.The following chemical equation,

HC2H3O2(aq) + KOH(aq) KC2H3O2(aq) + H2O(l),

is an example of a(n) _______ reaction.

a.oxidation-reduction and acid-base

b.acid-base

c.precipitation

d.oxidation-reduction and precipitation

e.oxidation-reduction

8.What substance is oxidized in the following reaction?

4HCl + MnO2 → Cl2 + 2H2O + MnCl2

a.Mn in MnO2

b.O in MnO2

c.Cl in HCl

d.H in HCl

9.What is the reducing agent in the following reaction?

4HCl + MnO2 → Cl2 + 2H2O + MnCl2

Cl2

MnCl2

HCl

MnO2

10.All redox reactions involve oxygen.

True

False

11.The term formula weight can be used with respect to which of the following?

A.ionic compounds

B.covalent compounds

C.both a and b

D.neither a nor b

12.What is the molecular weight of ibuprofen, C13H18O2?

A.206.3 amu

B.377.7 amu

C.29.0 amu

D.289.4 amu

13.The mass of an atom of 12C is exactly 12 atomic mass units. Which of the following describes a mole of 12C atoms?

A.a sample which weighs exactly 12 atomic mass units

B.a sample which contains 6.02 × 1023 atoms of 12C

C.both a and b

D.neither a nor b

14.The mass of an atom of 12C is exactly 12 atomic mass units. Which of the following describes a mole of 12C atoms?

A.a sample which contains 6.02 × 1023 atoms of 12C

B.a sample which weighs exactly 12.011 grams

C.both a and b

D.neither a nor b

15.What is the molar mass of water, H2O?

A.18.02 g

B.18.02 amu

C.17.01 g

D.17.01 amu

16.What is the molar mass of glucose, C6H12O6?

A.180.2 amu

B.180.2 g

C.60.05 amu

D.60.05 g

17.In the reaction 2H2O → 2H2 + O2, 2.0 mol water will produce how many grams of O2?

32

64

16

36

18.In the reaction 2CH4 + O2 → 2CO + 4H2, how many molecules of CO will be produced by the complete reaction of 1.60 grams of CH4?

3.01 × 1022

2.00

12.0 × 1023

6.02 × 1022

19.Suppose 2.43 g of magnesium is reacted with 3.20 g of oxygen: 2Mg + O2 → 2MgO. How many grams of MgO will be produced?

1.27

4.03

5.63

8.06

20.Which of the following conversion factors would allow one to calculate the amount of PbI2produced from a given amount of NaI in the following unbalanced reaction?

Pb(NO3)2 + Nal → Pbl2 + NaNO3

a.

b.

c.

d.

21.The unbalanced equation for the reduction of copper(I) sulfide with oxygen is given below. What mass of copper is produced from the reduction of 7.50 g Cu2S?

Cu2S(s) + O2(g) Cu(s) + SO2(g)

18.8 g

5.99 g

1.50 g

9.39 g

2.99 g

22.How many grams of aluminum oxide are produced by the complete reaction of 19.8 g aluminum with excess oxygen?

10.5 g aluminum oxide

37.4 g aluminum oxide

49.9 g aluminum oxide

74.8 g aluminum oxide

23.If 5 grams of CO and 5 grams of O2 are combined according to the reaction, which is the limiting reagent?

2CO + O2 → 2CO2

O2

CO and O2

CO2

CO

24.In an industrial process, nitrogen is reacted with hydrogen to produce ammonia. The percent yield of this particular process is 26%. How much hydrogen is needed to produce 4.8 kg ammonia?

1.5 kg

7.0 kg

0.85 kg

3.3 kg

25.A percentage yield greater than 100% has been reported in a scientific paper you are assigned to read. What would be a reasonable explanation for this?

a. The product was measured more than once.

b. It must be a typographical error since yields can't exceed 100%.

c. A lack of training of the professor who published the study.

d. Small measurement errors could have caused this to occur.

26.In an industrial process, nitrogen is reacted with hydrogen to produce ammonia. The percent yield of this particular process is 24.8%. How much hydrogen is needed to produce 3.7 kg ammonia?

1.8 kg

1.2 kg

4.4 kg

12 kg

2.7 kg

27.The following reaction has a percent yield of 90.5%. How many grams of carbon dioxide are produced from 78.5 g calcium carbonate via this reaction?

2 HNO3(aq) + CaCO3(aq) Ca(NO3)2(aq) + H2O(l) + CO2(g)

34.5 g

21.6 g

38.1 g

31.2 g

28.When gas molecules dissolve in liquids to form a saturated system, the process is usually

exothermic.

endothermic.

independent of the nature of the liquid.

temperature independent.

29.The reaction below would be considered.

CaCO3 + heat → CaO + CO2

an exothermic combination.

an exothermic decomposition.

an endothermic combination.

an endothermic decomposition.

30.The combustion of one mole of propane, C3H8, releases 531 kcal. How much heat is released by the combustion of 1.20 moles of propane?

A.584 kcal

B.690 kcal

C.443 kcal

D.637 kcal

31.The combustion of one mole of propane, C3H8, releases 531 kcal. How much heat is released by the combustion of 4.40 g of propane?

A.531 kcal

B.5.31 × 104 kcal

C.53.1 kcal

D.5.31 × 103 kcal

32.Metabolism of one mole of glucose, C6H12O6, releases 670 kcal. How much heat is released by the combustion of 0.300 moles of glucose?

A.201 kcal

B.2.41 × 103 kcal

C.186 kcal

D.2.23 × 103 kcal

33.Metabolism of one mole of glucose, C6H12O6, releases 6.70 × 102 kcal. How much heat is released by the combustion of 50.0 g of glucose?

A.201 kcal

B.2.41 × 103 kcal

C.186 kcal

D.2.23 × 103 kcal

1. Which characteristic below describes ONLY a solid (not liquid or gas)?
a) definite shape b) particles in contact c) definite volume d) completely fills container
2. When iron rusts, it forms a reddish-brown solid. This is:
a) a physical change b) a chemical change c) no change at all
3. What is the name of FeSO4?
a) iron (I) sulfate b) iron (II) sulfate c) iron sulfite d) iron sulfide
4. A bottle label states that the bottle contains “drinking water with minerals added for flavor. This would be an example of:
a) an element b) a compound c) a heterogeneous mixture d) a homogeneous mixture
5. Which answer has the correct number of significant figures for: length = 2.0 m + 0.2100 m?
a) 2.2 b) 2.21 c) 2.210 d) 2.2100
Place the answer with the correct number of significant figures on the lines provided below.
6. To drive one kilometer, how many centimeters should you drive?
_______________cm
7. A 10.0 gram block of gold has a density of 19.32 g/cm3. What is its volume?
______________cm3
8. What is the formula of sodium sulfide?
_________________________
9. What is the name of H2S?
_______________mm
10. How many neutrons are in 35Cl?
_______________ neutrons
For problems 11 through 13, show your work to receive full credit and use the correct number of significant figures in your final answer.
11. The density of nickel is 8.91 g/cm3. Calculate the mass of a nickel ball with a radius of 0.50 mm in grams.
(π = 3.1416; Vsphere = 4πr3/3)
12. The recommended adult dose of Elixophyllin , a drug used to treat asthma, is 6.00 mg/kg of body mass. Calculate the dose in milligrams for a 134-lb person.
13. It is 273 K outside. Do you need a jacket? Why or why not? (show your work for full credit)
14) Element X has three naturally occurring isotopes. The masses (amu) and % abundances of the isotopes are given in the table below. What is the average atomic mass of the element in amu?

1. Which characteristic below describes ONLY a solid (not liquid or gas)?
a) definite shape b) particles in contact c) definite volume d) completely fills container
2. When iron rusts, it forms a reddish-brown solid. This is:
a) a physical change b) a chemical change c) no change at all
3. What is the name of FeSO4?
a) iron (I) sulfate b) iron (II) sulfate c) iron sulfite d) iron sulfide
4. A bottle label states that the bottle contains “drinking water with minerals added for flavor. This would be an example of:
a) an element b) a compound c) a heterogeneous mixture d) a homogeneous mixture
5. Which answer has the correct number of significant figures for: length = 2.0 m + 0.2100 m?
a) 2.2 b) 2.21 c) 2.210 d) 2.2100
Place the answer with the correct number of significant figures on the lines provided below.
6. To drive one kilometer, how many centimeters should you drive?
_______________cm
7. A 10.0 gram block of gold has a density of 19.32 g/cm3. What is its volume?
______________cm3
8. What is the formula of sodium sulfide?
_________________________
9. What is the name of H2S?
_______________mm
10. How many neutrons are in 35Cl?
_______________ neutrons
For problems 11 through 13, show your work to receive full credit and use the correct number of significant figures in your final answer.
11. The density of nickel is 8.91 g/cm3. Calculate the mass of a nickel ball with a radius of 0.50 mm in grams.
(π = 3.1416; Vsphere = 4πr3/3)
12. The recommended adult dose of Elixophyllin , a drug used to treat asthma, is 6.00 mg/kg of body mass. Calculate the dose in milligrams for a 134-lb person.
13. It is 273 K outside. Do you need a jacket? Why or why not? (show your work for full credit)
14) Element X has three naturally occurring isotopes. The masses (amu) and % abundances of the isotopes are given in the table below. What is the average atomic mass of the element in amu?

isotope38 abundance of 5.07,mass of 37.919

isotope39x,abundance of 15.35,mass of 39.017

isotope 42,abundance of 79.85,mass of 42.111


15. Classify each of the following elements as alkali, alkaline earth, halogen or a noble gas:
a) He ________________________
b) F ________________________
c) Na ________________________
d) Ca ________________________
e) Br ________________________

41. If 25 mL of 0.055 MHCl are added to 35 mL of distilled H2O, what is thefinal pH

(A) 0.20
(B) 1.26
(C) 1.41
(D) 1.64



42. A solution prepared by dissolving 0.100 mole of propionicacid in enough water to make 1.00 L of solution is observed to havea pH = 2.94. What is the Ka for propionic acid?



(A) 1.3 x 10¯6
(B) 1.1 x 10¯3
(C) 1.3 x 10¯5
(D) 1.1 x 10¯2



43. When 0.1M aqueous solutions of the following salts arearranged in order of increasing basicity, what is the correctorder?


SALTS
I. NaCl
II. NH4Cl
III. NaHCO3



(A) I < II < III
(B) I < III < II
(C) II < I < III
(D) III < I < II


47. How many electrons are required to balance the half reactionin which dichromate ion, Cr2O72¯is converted to chromium(III) ions in acid solution?



(A) one
(B) five
(C) six
(D) eight



48. Solutions of Ag+, Cu2+,Fe3+ and Ti4+ are electrolyzed with aconstant current until 0.10 mol of metal is deposited. Which willrequire the greatest length of time?



(A) Ag+
(B) Cu2+
(C) Fe3+
(D) Ti4+



49. What type of radiation is emitted during a nuclear processin which a nucleas with a greater atomic number is formed?



(A) alpha particles
(B) beta particles
(C) positrons
(D) gamma rays



50. Which pair of elements is listed in order of decreasingfirst ionization energy?



(A) Na, Mg
(B) Mg, Al
(C) Al, Si
(D) Si, P



53. An element with a low melting point that does not conductelectricity would most likely be found on the periodic table



(A) in the upper right portion
(B) in the upper left portion
(C) in the lower left portion
(D) in the middle



54. The first three ionization energies of an element X are 590,1145, and 4912 kJ/mol. The most likely formula for a stable ion ofX is



(A) X+
(B) X2+
(C) X3+
(D) X¯



55. The highest oxidation state known for vanadium (Z = 23)is



(A) 2
(B) 3
(C) 4
(D) 5



56. Which have both ionic and covalent bonds?


SALTS
-------------
I. NH4Br
II. NaNO2



(A) I only
(B) II only
(C) both I and II
(D) neither I or II



57. How many valence electrons are present in the tetraborateion (B4O72¯)?



(A) 42
(B) 54
(C) 56
(D) 62



58. Which substance has the highest melting point?



(A) silicon carbide, SiC
(B) phosphorus pentachloride, PCl5
(C) sulfer, S8
(D) phosgene, COCl2



59. All of the following species are pyramidal in shapeexcept



(A) SO32¯
(B) NH3
(C) BF3
(D) H3O+



60. In which compounds in the liquid state does hydrogen bondingoccur?


Compounds
-----------------
I. ammonia
II. hydrogen peroxide
III. methane



(A) I only
(B) I and II only
(C) I and III only
(D) I, II, and III