CHM 123 Exam 1 and 2 info
Select the oxidation number for the indicated atom in the following molecules and ions: Pt in PtCl4^2-
+2
Select the oxidation number for the indicated atom in the following molecules and ions: Pt in PtCl6^2-
+4
Select the oxidation number for the indicated atom in the following molecules and ions: Ti in TiO2
+4
Select the oxidation number for the indicated atom in the following molecules and ions: Mo in MoO4^2-
+6
The reaction between nitric oxide (NO) and oxygen to form nitrogen dioxide (NO2) is a key step in photochemical smog formation: 2NO(g) + O2(g) → 2 NO2(g) How many grams of O2 are needed to produce 1.41 g of NO2?
.490 grams
Nitric oxide (NO) reacts with oxygen gas to form nitrogen dioxide (NO2), a dark brown gas: 2NO(g) + O2(g) → 2NO2(g) In one experiment, 0.879 mol of NO is mixed with 0.511 mol of O2. Determine which of the two reactants is the limiting reactant. Calculate also the number of moles of NO2 produced. Moles of NO2 produced:
.879 moles
The formula for rust can be represented by Fe2O3. How many moles of Fe are present in 25.2 g of the compound?
0.316 mol Fe
The formula for rust can be represented by Fe2O3. How many moles of Fe are present in 28.6 g of the compound?
0.358 mol Fe
Nitric oxide (NO) reacts with oxygen gas to form nitrogen dioxide (NO2), a dark brown gas: 2NO(g) + O2(g) → 2NO2(g) In one experiment, 0.885 mol of NO is mixed with 0.511 mol of O2. Determine which of the two reactants is the limiting reactant. Calculate also the number of moles of NO2 produced. Moles of NO2 produced
0.885 moles
How many moles of cobalt (Co) atoms are there in 7.00 × 10^9 (7.00 billion) Co atoms?
1.16 x 10^-14 mol
The annual production of sulfur dioxide from burning coal and fossil fuels, auto exhaust, and other sources is about 26 million tons. The equation for the reaction is S(s) + O2(g) →SO2(g) If 2.68 × 107 tons of sulfur dioxide formed, how many tons of sulfur were present in the original materials? Assume 100% yield.
1.34 x 10^7 tons
For many years chloroform (CHCl3) was used as an inhalation anesthetic in spite of the fact that it is also a toxic substance that may cause severe liver, kidney, and heart damage. Calculate the percent composition by mass of this compound to four significant figures. The following molar masses should be used in your calculation: H = 1.008 g/mol, C = 12.01 g/mol, Cl = 35.45 g/mol.
10.06% C .8444% H 89.09% Cl
Assume the atomic mass of element X is 22.99 amu. A 23.77−g sample of X combines with 131.21 g of another element Y to form a compound XY. Calculate the atomic mass of Y.
126.9 amu
Consider the combustion of butane (C4H10): 2C4H10(g) + 13O2(g) → 8CO2(g) + 10H2O(l) In a particular reaction, 3.40 moles of C4H10 are reacted with an excess of O2. Calculate the number of moles of CO2 formed.
13.6 mol CO2
Calculate the molar mass of (NH4)2SO4.
132.15 g/mol
Calculate the mass of FeS formed when 9.42 g of iron reacts with 8.50 g of sulfur according to the following reaction. Fe(s) + S(s) → FeS(s)
14.8 grams
Calculate the number of grams of Al in 271 g of Al2O3
143.4
Calculate the molecular mass or formula mass (in amu) of each of the following substances: (a) NaI
149.9 amu
Consider the combustion of butane (C4H10): 2C4H10(g) + 13O2(g) → 8CO2(g) + 10H2O(l) In a particular reaction, 4.00 moles of C4H10 are reacted with an excess of O2. Calculate the number of moles of CO2 formed.
16 mol CO2
Calculate the molecular mass or formula mass (in amu) of each of the following substances: (a) CH4
16.04 amu
The analysis of a compound gives the following percent composition by mass: C: 58.08 percent; H: 10.04 percent; S: 9.123 percent; O: 22.76 percent. What is its molecular formula given that its molar mass is 351.5 g?
17 C atoms 35 H atoms 1 S atoms 5 O atoms
what is the % comp of N in Ca(NO3)2
17.07%
Calculate the number of grams of Al in 321 g of Al2O3
170 grams
Calculate the molecular mass or formula mass (in amu) of each of the following substances: K2SO4
174.27 amu
what is the mass in grams of a single atom of Sb
2.023 x 10^-22
Consider the combustion of carbon monoxide (CO) in oxygen gas: 2CO(g) + O2(g) → 2CO2(g) Starting with 2.85 moles of CO, calculate the number of moles of CO2 produced if there is enough oxygen gas to react with all the CO.
2.85 mol CO2
How many moles of magnesium (Mg) are there in 69.3 g of Mg?
2.85 mol Mg
When heated, lithium reacts with nitrogen to form lithium nitride: 6Li(s) + N2(g) → 2Li3N(s) What is the theoretical yield of Li3N in grams when 12.2 g of Li is heated with 33.3 g of N2?
20.4
If 0.86 mole of MnO2 and 43.0 g of HCl react, how many grams of Cl2 will be produced? MnO2 + 4HCl → MnCl2 + Cl2 + 2H2O
20.9 grams
When heated, lithium reacts with nitrogen to form lithium nitride: 6Li(s) + N2(g) → 2Li3N(s) What is the theoretical yield of Li3N in grams when 12.8 g of Li is heated with 34.9 g of N2?
21.4 grams
Calculate the number of grams of Al in 411 g of Al2O3
217 grams
The reaction between aluminum and iron(III) oxide can generate temperatures approaching 3000°C and is used in welding metals: 2Al + Fe2O3 → Al2O3 +2Fe In one process, 115 g of Al are reacted with 601 g of Fe2O3. Calculate the mass (in grams) of Al2O3 formed, and determine the amount of excess reagent left at the end of the reaction. mass of Al2O3 formed:
217 grams
Methanol (CH3OH) burns in air according to the equation 2CH3OH + 3O2 →2CO2 + 4H2O If 203 g of methanol are used up in a combustion process, what is the mass of H2O produced?
228 grams
If 0.86 mole of MnO2 and 48.3 g of HCl react, how many grams of Cl2 will be produced? MnO2 + 4HCl → MnCl2 + Cl2 + 2H2O
23.5 grams
When heated, lithium reacts with nitrogen to form lithium nitride: 6Li(s) + N2(g) → 2Li3N(s) If the actual yield of Li3N is 5.65 g, what is the percent yield of the reaction?
26.4%
The reaction between aluminum and iron(III) oxide can generate temperatures approaching 3000°C and is used in welding metals: 2Al + Fe2O3 → Al2O3 +2Fe In one process, 115 g of Al are reacted with 601 g of Fe2O3. Calculate the mass (in grams) of Al2O3 formed, and determine the amount of excess reagent left at the end of the reaction. amount of excess reagent left
261 g
Write the net ionic equation for the reaction between AgNO3(aq) and Na2SO4(aq). Be sure to include states of matter in your answer.
2Ag+(aq) + SO4^2-(aq) -> Ag2SO4(s)
balance the following equation C + O2 --> CO
2C + O2 --> 2CO
Butane is reacted with oxygen gas to form carbon dioxide and water. Write the balanced reaction (omit state symbols (s), (l), (g), (aq), etc.). C4H10 + O2 ---> CO2 + H2O
2C4H10 + 13O2 → 8CO2 + 10H2O
Balance the following equation K + H2O --> KOH + H2
2K + 2H2O --> 2KOH + H2
What is the coefficient of H2O when the equation below is properly balanced?___ PCl3(l) + ___ H2O(l) → ___ H3PO3(aq) + ___ HCl(aq)
3
Calculate the number of atoms in 0.236 g of potassium (K).
3.63 x 10^21
Calculate the number of atoms in 0.245 g of potassium (K).
3.77 x 10^21
When heated, lithium reacts with nitrogen to form lithium nitride: 6Li(s) + N2(g) → 2Li3N(s) If the actual yield of Li3N is 6.49 g, what is the percent yield of the reaction?
31.8%
Calculate the molecular mass or formula mass (in amu) of each of the following substances: Ca3(PO4)2
310.18
Calculate the mass in grams of iodine (I2) that will react completely with 22.9 g of aluminum (Al) to form aluminum iodide (AlI3).
323.1 g I2
Calculate the mass in grams of iodine (I2) that will react completely with 23.2 g of aluminum (Al) to form aluminum iodide (AlI3).
327 grams I2
Calculate the mass in grams of iodine (I2) that will react completely with 23.3 g of aluminum (Al) to form aluminum iodide (AlI3).
329 grams I2
Fermentation is a complex chemical process of wine making in which glucose is converted into ethanol and carbon dioxide: C6H12O6 → 2C2H5OH + 2CO2 Starting with 754.5 g of glucose, what is the maximum amount of ethanol in grams and in liters that can be obtained by this process (density of ethanol = 0.789 g/mL)?
385.9 g .489 L
balance the following equation KOH + H3PO4 --> K3PO4 + H2O
3KOH + H3PO4 --> K3PO4 + 3 H2O
How many moles of magnesium (Mg) are there in 97.3 g of Mg?
4.00 mol Mg
Calculate the molecular mass or formula mass (in amu) of each of the following substances: (b) NO2
46.01 amu
Calculate the number of grams of lead (Pb) in 22.4 moles of lead.
4640 grams
Fermentation is a complex chemical process of wine making in which glucose is converted into ethanol and carbon dioxide: C6H12O6 → 2C2H5OH + 2CO2 Starting with 930.6 g of glucose, what is the maximum amount of ethanol in grams and in liters that can be obtained by this process (density of ethanol = 0.789 g/mL)?
476.1 g .603 L
what is the mass of 1.223 mol of Iron(III) sulfate
489.0 grams Fe2(SO4)3
A modern penny weighs 2.5500 g but contains only 0.0585 g of copper (Cu). How many copper atoms are present in a modern penny?
5.54 x 10^20 Cu atoms
A modern penny weighs 2.7150 g but contains only 0.0615 g of copper (Cu). How many copper atoms are present in a modern penny?
5.83 x 10^20 Cu atoms
Determine the number of atoms of each element in the empirical formula of a compound with the following composition: 54.95 percent C, 8.455 percent H, 36.60 percent O.
6 C atoms 11 H atoms 3 O atoms
What is the mass in grams of a single atom of He?
6.647 x 10^-24 grams
The atomic masses of the two stable isotopes of copper, 63Cu29 (69.17 percent) and 65Cu29 (30.83 percent), are 62.9296 amu and 64.9278 amu, respectively. Calculate the average atomic mass of copper.
63.55 amu
Determine the number of atoms of each element in the empirical formula of a compound with the following composition: 65.08 percent C, 10.14 percent H, 24.77 percent O.
7 C atoms 13 H atoms 2 O atoms
The reaction of 60.0 g of aluminum oxide with 30.0 g of carbon produced 22.5 g of aluminum. What is the percent yield for this reaction? Al2O3 + 3C → 2Al + 3CO
70.9%
Assume the atomic mass of element X is 22.99 amu. A 67.98−g sample of X combines with 236.26 g of another element Y to form a compound XY. Calculate the atomic mass of Y.
79.81 amu
Calculate the number of atoms in 0.564 g of potassium (K).
8.69 x 10^21 atoms
The density of water is 1.00 g/mL at 4°C. How many water molecules are present in 2.66 mL of water at this temperature?
8.89 x 10^22 molecules
Industrially, vanadium metal, which is used in steel alloys, can be obtained by reacting vanadium(V) oxide with calcium at high temperatures: 5Ca + V2O5 5CaO + 2V In one process, 1.540 ×10^3 g of V2O5 react with 2.000 × 103 g Ca. Calculate the theoretical yield of V
862.6 grams
Industrially, vanadium metal, which is used in steel alloys, can be obtained by reacting vanadium(V) oxide with calcium at high temperatures: 5Ca + V2O5 5CaO + 2V In one process, 1.540 ×10^3 g of V2O5 react with 2.000 × 103 g Ca. Calculate the theoretical yield of V.
862.6 grams
Industrially, vanadium metal, which is used in steel alloys, can be obtained by reacting vanadium(V) oxide with calcium at high temperatures: 5Ca + V2O5 → 5CaO + 2V In one process, 1.540 × 103 g of V2O5 react with 2.030 × 103 g Ca. (a) Calculate the theoretical yield of V.
863 9/18
Industrially, vanadium metal, which is used in steel alloys, can be obtained by reacting vanadium(V) oxide with calcium at high temperatures: 5Ca + V2O5 5CaO + 2V In one process, 1.540 ×10^3 g of V2O5 react with 2.000 × 103 g Ca. Calculate the percent yield if 773.0 g of V are obtained.
89.61%
Ammonia is a principal nitrogen fertilizer. It is prepared by the reaction between hydrogen and nitrogen. 3H2(g) + N2(g)→ 2NH3(g) In a particular reaction, 6.00 moles of NH3 were produced. How many moles of H2 and how many moles of N2 were reacted to produce this amount of NH3?
9 mol H2 3 mol N2
Ammonia is a principal nitrogen fertilizer. It is prepared by the reaction between hydrogen and nitrogen. 3H2(g) + N2(g) → 2NH3(g) In a particular reaction, 6.00 moles of NH3 were produced. How many moles of H2 and how many moles of N2 were reacted to produce this amount of NH3?
9.00 mol H2 3.00 mol N2
Industrially, vanadium metal, which is used in steel alloys, can be obtained by reacting vanadium(V) oxide with calcium at high temperatures: 5Ca + V2O5 5CaO + 2V In one process, 1.540 ×10^3 g of V2O5 react with 2.000 × 103 g Ca. Calculate the percent yield if 777.0 g of V are obtained.
90.08%
Industrially, vanadium metal, which is used in steel alloys, can be obtained by reacting vanadium(V) oxide with calcium at high temperatures: 5Ca + V2O5 → 5CaO + 2V In one process, 1.540 × 103 g of V2O5 react with 2.030 × 103 g Ca. (b) Calculate the percent yield if 807.0 g of V are obtained.
93.5
A compound with an empirical formula of C2H4Br has a molar mass of 215.90 g/mol. What is the molecular formula?
C4H8Br2
An unknown compound with a molar mass of 155.06 g/mol consists of 46.47% C, 7.80% H, and 45.72% Cl. Find the molecular formula for the compound.
C6H12Cl2
Vanadium(V) oxide reacts with calcium according to the chemical equation below. When 10.0 moles of V2O5 are mixed with 10.0 moles of Ca, which is the limiting reagent?V2O5(s) + 5Ca(l) → 2V(l) + 5CaO(s)
Ca
Nitric acid is a strong oxidizing agent. State which of the following species is least likely to be produced when nitric acid reacts with a strong reducing agent such as zinc metal: N2O4 NO2 N2O N2O5 NO NH4+
H2O5
In which of the following species does the sulfur atom have the highest oxidation number? H2S S8 H2SO4 S2−
H2SO4
In which of the following species does the sulfur atom have the lowest oxidation number? HS− SO2 SO3
HS-
balance the following equation N2 + H2 --> NH3
N2 + 3H2 --> 2NH3
Nitric oxide (NO) reacts with oxygen gas to form nitrogen dioxide (NO2), a dark brown gas: 2NO(g) + O2(g) → 2NO2(g) In one experiment, 0.879 mol of NO is mixed with 0.511 mol of O2. Determine which of the two reactants is the limiting reactant. Calculate also the number of moles of NO2 produced. Limiting reactant:
NO
Nitric oxide (NO) reacts with oxygen gas to form nitrogen dioxide (NO2), a dark brown gas: 2NO(g) + O2(g) → 2NO2(g) In one experiment, 0.885 mol of NO is mixed with 0.511 mol of O2. Determine which of the two reactants is the limiting reactant. Calculate also the number of moles of NO2 produced. Limiting reactant:
NO
Determine the empirical formula of a compound containing 2.06 g of silicon and 10.4 g of chlorine.
SiCl4
Determine the empirical formula of a compound containing 3.61 g of silicon and 18.2 g of chlorine.
SiCl4
Determine the empirical formula of a compound containing 3.81 g of silicon and 19.2 g of chlorine.
SiCl4
The compound HPO42− is
both a bronsted acid and base
the passage of electricity through an electrolyte solution is caused by the movement of:
both cations and anions
There are two stable isotopes of chlorine: chlorine-35, with a mass of 34.968853 amu; and chlorine-37, with a mass of 36.965903. Given that the average atomic mass of a chlorine atom is 35.45 amu, which of the following statements is true?
chlorine contains more 35/17 Cl than 37/17 Cl.
true or false a mole of NaNO3 contains a mole of oxygen formula weight
false
amu
mass of element
Identify each of the following substances as a strong electrolyte, weak electrolyte, or nonelectrolyte: (e) C12H22O11
nonelectrolyte
identify the following compounds as a weak or strong acid or base: NaOH
strong base
Identify each of the following substances as a strong electrolyte, weak electrolyte, or nonelectrolyte: (b) KCl
strong electrolyte
Identify each of the following substances as a strong electrolyte, weak electrolyte, or nonelectrolyte: (c) HNO3
strong electrolyte
formula weight
the sum of the atomic weights of the atoms in the chemical formula of the substance
identify the following compounds as a weak or strong acid or base: H3PO4
weak acid
identify the following compounds as a weak or strong acid or base: HCOOH
weak acid
Identify the following compounds as a weak or strong acid or base: NH3
weak base
Identify each of the following substances as a strong electrolyte, weak electrolyte, or nonelectrolyte: (a) H2O
weak electrolyte
Identify each of the following substances as a strong electrolyte, weak electrolyte, or nonelectrolyte: (d) CH3COOH
weak electrolyte
