Questions and Answers of General Chemistry

The acidic constituent in vinegar is acetic acid. A 10.0-mL sample of a certain vinegar contains 611 mg of acetic acid. What is this mass of acetic acid expressed in micrograms?
Sodium hydrogen carbonate, known commercially as baking soda, reacts with acidic materials such as vinegar to release carbon dioxide gas. An experiment calls for 0.450 kg of sodium hydrogen
A mineral sample has a mass of 5.94 g and a volume of 0.73 cm3. The mineral is either sphalerite (density = 4.0 g/cm3), cassiterite (density 5 6.99 g/cm3), or cinnabar (density = 8.10 g/cm3). Which
Which of the following are pure substances and which are mixtures? For each, list all of the different phases present.a. A sugar solution with sugar crystals at the bottomb. Ink containing a liquid
A flask contains a 30.0 mL sample of acetone (nail polish remover) that weighs 23.6 grams. What is the density of the acetone?
The reaction of oxygen and hydrogen is used to propel rockets. Liquid oxygen has a boiling point of - 222.7°C. What is this temperature in degrees Fahrenheit?
Salt and ice are stirred together to give a mixture to freeze ice cream. The temperature of the mixture is - 20.0°C. What is this temperature in degrees Fahrenheit?
Convert:a. 51°F to degrees Celsiusb. - 11°F to degrees Celsiusc. - 41°C to degrees Fahrenheitd. 22°C to degrees Fahrenheit
Convert:a. 68°F to degrees Celsiusb. - 23°F to degrees Celsiusc. 26°C to degrees Fahrenheitd. - 81°C to degrees Fahrenheit
A solid circular cylinder of iron with a radius of 1.500 cm has a ruler etched along its length. What is the volume of iron contained between the marks labeled 3.20 cm and 3.50 cm? The volume of a
One sphere has a radius of 4.52 cm; another has a radius of 4.72 cm. What is the difference in volume (in cubic centimeters) between the two spheres? Give the answer to the correct number of
How many significant figures are there in each of the following measurements?a. 57.00 gb. 0.0503 kgc. 6.310 Jd. 0.80090 me. 5.06 × 10-7 cmf. 2.010 s
All of the following processes involve a separation of either a mixture into substances or a compound into elements. For each, decide whether a physical process or a chemical reaction is required.a.
Give the normal state (solid, liquid, or gas) of each of the following.a. Potassium hydrogen tartrate (cream of tartar)b. Tungstenc. Carbon (graphite)d. Mercury
Aluminum metal reacts with bromine, a red-brown liquid with a noxious odor. The reaction is vigorous and produces aluminum bromide, a white crystalline substance. A sample of 27.0 g of aluminum
Zinc metal reacts with yellow crystals of sulfur in a fiery reaction to produce a white powder of zinc sulfide. A chemist determines that 65.4 g of zinc reacts with 32.1 g of sulfur. How many grams
A 15.5 g sample of sodium carbonate is added to a solution of acetic acid weighing 19.7 g. The two substances react, releasing carbon dioxide gas to the atmosphere. After reaction, the contents of
If a molecule is an “ene-one,” what functional groups must it have?
Adenine and guanine are members of a class of molecules known as purines; they have two rings in their structure. Thymine and cytosine, on the other hand, are pyrimidines, and have only one ring in
Draw the condensed structures of the compounds formed from(a) Butanoic acid and methanol,(b) Benzoic acid and 2-propanol,(c) Propanoic acid and dimethylamine. Name the compound in each case.
Write the condensed structural formulas for as many alkenes and alkynes as you can think of that have the molecular formula C6H10.
Give the general formula for any cyclic alkene, that is, a cyclic hydrocarbon with one double bond.
What are the approximate bond angles(a) About carbon in an alkane,(b) About a doubly bonded carbon atom in an alkene,(c) About a triply bonded carbon atom in an alkyne?
What are the characteristic hybrid orbitals employed by(a) Carbon in an alkane,(b) Carbon in a double bond in an alkene,(c) Carbon in the benzene ring,(d) carbon in a triple bond in an alkyne?
The complex [Ru(EDTA)(H2O)]- undergoes substitution reac-tions with several ligands, replacing the water molecule with the ligand. In all cases the ruthenium stays in the +3 oxidation state and the
A Cu electrode is immersed in a solution that is 1.00 M in [Cu(NH3)4]2+ and 1.00 M in NH3. When the cathode is a standard hydrogen electrode, the emf of the cell is found to be +0.08 V. What is the
Oxyhemoglobin, with an O2 bound to iron, is a low-spin Fe(II) complex; deoxyhemoglobin, without the O2 molecule, is a high-spin complex.(a) Assuming that the coordination environment about the metal
Which of the following objects is chiral:(a) A left shoe,(b) A slice of bread,(c) A wood screw,(d) A molecular model of Zn(en)Cl2,(e) A typical golf club?
Sketch the structure of the complex in each of the following compounds and give the full compound name:(a) cis-[Co(NH3)4(H2O)2](NO3)2(b) Na2[Ru(H2O)Cl5](c) trans-NH4[Co(C2O4)2(H2O)2](d)
Based on the molar conductance values listed here for the series of platinum(IV) complexes, write the formula for each complex so as to show which ligands are in the coordination sphere of the metal.
(a) Sketch a diagram that shows the definition of the crystal-field splitting energy (Δ) for an octahedral crystal field.(b)What is the relationship between the magnitude of Δ and the energy of the
Explain why the dxy, dxz, and orbitals lie lower in energy than the dz2 and dx2-y2 orbitals in the presence of an octahedral arrangement of ligands about the central metal ion.
In crystal-field theory, ligands are modeled as if they are point negative charges. What is the basis of this assumption, and how does it relate to the nature of metal–ligand bonds?
If a transition-metal complex has an even number of valence d electrons, does it necessarily mean that the complex is diamagnetic? Explain.
Is it possible for a low-spin octahedral Fe(II) complex to be paramagnetic? Explain.
Indicate the likely coordination number of the metal in each of the following complexes:(a) [Rh(bipy)3](NO3)3(b) Na3[Co(C2O4)2Cl2](c) [Cr(o-phen)3](CH3COO)3(d) Na2[Co(EDTA)Br]
Select the member of group 4A that best fits each description:(a) Forms chains to the greatest extent,(b) Forms the most basic oxide,(c) Is a metalloid that can form 2+ ions.
Write complete balanced half-reactions for(a) Reduction of nitrate ion to NO in acidic solution,(b) Oxidation of HNO2 to NO2 in acidic solution.
Identify the following hydrides as ionic, metallic, or molecular:(a) B2H6,(b) RbH,(c) Th4H1.5.
Identify each of the following elements as a metal, nonmetal, or metalloid:(a) Gallium,(b) Molybdenum,(c) Tellurium,(d) Arsenic,(e) Xenon,(f) Ruthenium.
When two protons fuse in a star, the product is 2H plus a positron (Equation 21.26).Why do you think the more obvious product of the reaction, 2He, is unstable?Equation 21.26 |H + }H → }H + 9e H +
Which are classified as ionizing radiation: X-rays, alpha particles, microwaves from a cell phone, and gamma rays?
Complete and balance the nuclear equations for the following fission or fusion reactions:(a)(b) 구H + H→3He
What is meant by enriched uranium? How is enriched uranium different from natural uranium?
What is the most common fissionable isotope in a commercial nuclear power reactor?
An analytical laboratory balance typically measures mass to the nearest 0.1 mg.What energy change would accompany the loss of 0.1 mg in mass?
Write balanced equations for each of the following nuclear reactions:(a) 23892U(n, γ)23992U,(b) 147N(p, α)116C,(c) 188O(n, β)199F
In 1930 the American physicist Ernest Lawrence designed the first cyclotron in Berkeley, California. In 1937 Lawrence bombarded a molybdenum target with deuterium ions, producing for the first time
Give the symbol for(a) A proton,(b) A beta particle,(c) A positron.
A certain constant-pressure reaction is nonspontaneous at45°C. The entropy change for the reaction is 72 J/K. What can you conclude about the sign and magnitude of ΔH?
The crystalline hydrate Cd(NO3)2 ∙ 4H2O(s) loses water when placed in a large, closed, dry vessel:This process is spontaneous and ΔH is positive. Is this process an exception to Bertholet’s
Fluoridation of drinking water is employed in many places to aid in the prevention of tooth decay. Typically the F- ion concentration is adjusted to about 1 ppb. Some water sup-plies are also "hard";
Fluoridation of drinking water is employed in many places to aid in the prevention of tooth decay. Typically the F- ion concentration is adjusted to about 1 ppb. Some water sup-plies are also "hard";
Fluoridation of drinking water is employed in many places to aid in the prevention of tooth decay. Typically the F— ion concentration is adjusted to about 1 ppb. Some water sup-plies are also
A concentration of 10-100 parts per billion (by mass) of Ag+ is an effective disinfectant in swimming pools. How-ever, if the concentration exceeds this range, the Ag+ can cause adverse health
The osmotic pressure of a saturated solution of strontium sulfate at 25°c is 21 torr. What is the solubility product of this salt at25°?
Excess Ca(OH)2 is shaken with water to produce a saturated solution. The solution is filtered, and a 50.00-mL sample titrated with HCl requires 11.23 mL of 0.0983 M HCl to reach the end point.
What is the pH at 25 °C of water saturated with CO2 at a partial pressure of 1.10 atm? The Henry's law constant for CO2 at 25 °C is 3.1 × 102 mol/L-atm. The CO2 is an acidic oxide, reading with
Aspirin has the structural formulaAt body temperature (37°C), Ka for aspirin equals 3 × 10-5. If two aspirin tablets, each having a mass of 325 mg, are dissolved in a full stomach whose volume is 1
A sample of 7.5 L of NH3 gas at 22°C and 735 torr is bubbled into a 0.50-L solution of 0.40 M HCl. Assuming that all the NH3 dissolves and that the volume of the solution remains 0.50 L, calculate
(a) A 0.1044-g sample of an unknown monoprotic acid requires 22.10 mL of 0.0500 M NaOH to reach the end point. What is the molecular weight of the unknown?(b) As the acid is titrated, the pH of the
(a) Write the net ionic equation for the reaction that occurs when a solution of hydrochloric acid (HCl) is mixed with a solution of sodium formate (NaCHO2).(b) Calculate the equilibrium constant for
The value of Ksp for Cd(OH)2 is 2.5 × 10-14.(a) What is the molar solubility of Cd(OH)2?(b) The solubility of Cd(OH)2 can be increased through formation of the complex ion CdBr42- (Kf = 5 ×
The solubility product for Zn(OH)2 is 3.0 × 10-16. The for-mation constant for the hydroxo complex, Zn(OH)42-, is 4.6 × 1017. What concentration of OH- is required to dissolve 0.015 mol of Zn(OH)2
The value of Ksp for Mg3(AsO4)2 is 2.1 × 10-20. The AsO43- ion is derived from the weak acid H3AsO4 (pKa1, = 2.22; PKa2 = 6.98; pKa3 = 11.50). When asked to calculate the molar solubility of
A buffer of what pH is needed to give a Mg2+ concentration of 3.0 × 10-2 M in equilibrium with solid magnesium oxalate?
The solubility products of PbSO4 and SrSO4 are 6.3 × 107 and 3.2 × 107, respectively. What are the values of [SO42-], [Pb2+], and [Sr2+] in a solution at equilibrium with both substances?
Calculate the ratio of [Ca2+] to [Fe2+] in a lake in which the water is in equilibrium with deposits of both CaCO3 and FeCO3. Assume that the water is slightly basic and that the hydrolysis of the
The solubility-product constant for barium permanganate, Ba(MnO4)2, is 2.5 × 10-10. Assume that solid Ba(MnO4)2 is in equilibrium with a solution of KMnO4.What concentration of KMnO4 is
Calculate the solubility of Mg(OH)2 in 0.50 M NH4Cl.
Use the solubility-product constant for Cr(OH)3 (Ksp = 6.7 × 10-31) and the formation constant for Cr(OH)4 from Table 17.1 to determine the concentration of Cr(OH)4 in a solution that is buffered at
Tooth enamel is composed of hydroxyapatite, whose simplest formula is Ca5(PO4)3OH, and whose corresponding Ksp = 6.8 × 10-27.As discussed in the “Chemistry and Life” box on page 730, fluoride in
The solubility of CaCO3 is pH dependent.a) Calculate the molar solubility of CaCO3 (Ksp = 4.5 × 10-9) neglecting the acid–base character of the carbonate ion.(b) Use the expression for the CO32-
For each pair of compounds, use Ksp values to determine which has the greater molar solubility:(a) CdS or CuS,(b) PbCO3 or BaCrO4,(c) Ni(OH)2 or NiCO3,(d) AgI or Ag2SO4.
A person suffering from anxiety begins breathing rapidly and as a result suffers alkalosis, an increase in blood pH.(a) Using Equation 17.10, explain how rapid breathing can cause the pH of blood to
How many microliters of 1.000 M NaOH solution must be added to 25.00 mL of a 0.1000 M solution of lactic acid [CH3CH(OH)COOH or HC3H5O3] to produce a buffer with pH = 3.75?
Suppose you want to do a physiological experiment that calls for a pH 6.50 buffer. You find that the organism with which you are working is not sensitive to the weak acid H2X or its sodium
What is the pH of a solution made by mixing 0.30 mol NaOH, 0.25 mol Na2HPO4, and 0.20 mol H3PO4 with water and diluting to 1.00 L?
A hypothetical weak acid, HA, was combined with NaOH in the following proportions: 0.20 mol of HA, 0.080 mol of NaOH. The mixture was diluted to a total volume of 1.0 L and the pH measured.(a) If pH
Show that the pH at the halfway point of a titration of a weak acid with a strong base (where the volume of added base is half of that needed to reach the equivalence point) is equal to pKa for the
A sample of 0.1687 g of an unknown monoprotic acid was dissolved in 25.0 mL of water and titrated with 0.1150 M NaOH. The acid required 15.5 mL of base to reach the equivalence point.(a) What is the
A sample of 0.2140 g of an unknown monoprotic acid was dissolved in 25.0 mL of water and titrated with 0.0950 M NaOH. The acid required 27.4 mL of base to reach the equivalence point.(a) What is the
A biochemist needs 750 mL of an acetic acid–sodium acetate buffer with pH 4.50. Solid sodium acetate (CH3COONa) and glacial acetic acid (CH3COOH) are available. Glacial acetic acid is 99% CH3COOH
Two buffers are prepared by adding an equal number of moles of formic acid (HCOOH) and sodium formate (HCOONa) to enough water to make 1.00 L of solution. Buffer A is prepared using 1.00 mol each of
Equal quantities of 0.010 M solutions of an acid HA and a base B are mixed. The pH of the resulting solution is 9.2.(a) Write the equilibrium equation and equilibrium-constant expression for the
The acid–base indicator bromcresol green is a weak acid. The yellow acid and blue base forms of the indicator are present in equal concentrations in a solution when the pH is 4.68.What is the for
Furoic acid (HC5H3O3) has a Ka value of 6.76 × 10-4 at 25 °C. Calculate the pH at 25 °C of(a) A solution formed by adding 25.0 g of furoic acid and 30.0 g of sodium furoate (NaC5H3O3) to enough
Use information from Appendix D to calculate the pH of(a) A solution that is 0.250 M in sodium formate (HCOONa) and 0.100 M in formic acid (HCOOH);(b) A solution that is 0.510 M in pyridine (C5H5N)
What is the name given to the kind of behavior demonstrated by a metal hydroxide in this graph? pH Solubility
Deuterium oxide (D2O, where D is deuterium, the hydrogen-2 isotope) has an ion-product constant, Kw, of 8.0 × 10-16 at 20°C. Calculate [D+] and [OD-] for pure (neutral) D2O at this temperature.
Deuterium oxide (D2O, where D is deuterium, the hydrogen-2 isotope) has an ion-product constant, Kw, of 8.0 × 10-16 at 20°C. Calculate [D+] and [OD-] for pure (neutral) D2O at this temperature.
Suppose that you worked at the U.S. Patent Office and a patent application came across your desk claiming that a newly developed catalyst was much superior to the Haber catalyst for ammonia synthesis
Write the equilibrium-constant expression for the equilibriumThe table that follows shows the relative mole percentages of CO2(g) and CO(g) at a total pressure of 1 atm for several temperatures.
If Kc = 1 for the equilibrium 2A(g) ⇌ B(g), what is the relationship between [A] and [B] at equilibrium?`
At 900 K the following reaction has Kp = 0.345:In an equilibrium mixture the partial pressures of SO2 and O2 are 0.135 atm and 0.455 atm, respectively.What is the equilibrium partial pressure of
Gaseous hydrogen iodide is placed in a closed container at 425°C, where it partially decomposes to hydrogen and idine:2HI(g) ⇌ H2(g) + I2(g).At equilibrium it is found that [HI] = 3.53 × 10-3M,
Consider the equilibrium Na2O(s) + SO2(g) ⇌ Na2SO3(s).(a) Write the equilibrium-constant expression for this reaction in terms of partial pressures.(b) All the compounds in this reaction are
Consider the equilibrium Na2O(s) + SO2(g) ⇌ Na2SO3(s).(a) Write the equilibrium-constant expression for this reaction in terms of partial pressures.(b) All the compounds in this reaction are
Mercury(I) oxide decomposes into elemental mercury and elemental oxygen: .(a)Write the equilibrium-constant expression for this reaction in terms of partial pressures.(b) Suppose you run this
Which of the following reactions lies to the right, favoring the formation of products, and which lies to the left, favoring formation of reactants?(a) (b) 2 NO(g) + O2(g) =2 NO,(g); K, = 5.0 X

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