chem 111
A weak electrolyte exists predominantly as ________ in solution.
molecules
MoO3
molybdenum(VI) oxide
An atom of iron is represented by 5726Fe. How many neutrons are in the nucleus of this atom?
neutrons in 57/26Fe = 31
What is the formula for pentane?
C5H12
An element cannot ________.
be separated into other substances by chemical means
A gas is sold for approximately 0.55 cents per milligram. What is its price in dollars per kilogram?
$5.5 × 10^3/kg
Given the data in the table below, ΔH°rxn for the reaction 2Ag2S (s) + O2 (g) → 2Ag2O (s) + 2S (s) is ________ kJ.
+3.2
How many sulfur dioxide molecules are there in 0.180 mol of sulfur dioxide?
1.08 × 1023
How many sulfur dioxide molecules are there in 1.80 mol of sulfur dioxide?
1.08 × 1024
How many sulfur dioxide molecules are there in 0.180 mol of sulfur dioxide?
1.08 × 10^23
What is the correct formula weight of iron(III) hydroxide?
106.8 amu
Which species has 48 electrons?
118/50 Sn^+2
Aluminum reacts with chlorine gas to form aluminum chloride via the following reaction: 2Al(s)+3Cl2(g)→2AlCl3(s) What is the maximum mass of aluminum chloride that can be formed when reacting 10.0 g of aluminum with 15.0 g of chlorine?
18.8 g
The value of ΔH° for the reaction below is -72 kJ. ________ kJ of heat are released when 5.0 mol of HBr is formed in this reaction. H2 (g) + Br2 (g) → 2HBr (g)
180
How much beverage is left over?
1×104 L
The correct answer (reported to the proper number of significant figures) to the following is ________. 6.3 × 3.25 = ________
20
Calculate the average percentage for the first set of data.
22.51
Calculate the average percentage for the second set of data
22.61
The element X has three naturally occurring isotopes. The masses (amu) and % abundances of the isotopes are given in the table below. The average atomic mass of the element is ________ amu. isotope abund mass 221x 74.22 220.9 220x 12.78 220.0 218x 13.00 218.1
220.4
Of the following, ________ is the largest mass.
284.7 Tg
Precision can be judged by examining the average of the deviations from the average value for that data set. Calculate the average value of the absolute deviations of each measurement from the average for the first set.
2x10^-10
The volume of a regular cylinder is V =πr2h. Using the value 3.1416 for the constant π, the volume (cm3) of a cylinder of radius 2.34 cm and height 19.91 cm expressed to the correct number of significant figures is ________.
342
How many protons are there in one atom of 88Sr?
38
How many milliliters of coconut oil weigh 4.71 grams if the density of coconut oil is 0.925 g/cm3?
5.09 mL
The energy of a photon that has a frequency of 8.21 × 1015 s-1 is ________ J.
5.44 × 10-18
An automobile's luggage compartment has a volume of 1.55 × 105 cm3. What is its volume in ft3?
5.47 ft3
reaction. This can be gleaned from the third postulate in Dalton's series. Magnesium oxide decomposes into magnesium and oxygen. If 16.12 g of magnesium oxide decomposes to form 9.72 g of magnesium, what mass of oxygen gas is also released in the reaction?
6.40g
A slice of apple pie contains 14.0 grams of fat, 2.00 grams of protein, and 52.0 grams of carbohydrate. The respective fuel values for protein, fat, and carbohydrate are 17, 38, and 17 kJ/g, respectively. If cycling typically burns 1000.0 kJ/hour, ________ minutes of cycling are required to completely burn off the slice of pie.
87
Aluminum sulfide reacts with water to form aluminum hydroxide and hydrogen sulfide. Write the balanced chemical equation for this reaction.
Al2S3(s)+6H2O(l)→2Al(OH)3(s)+3H2S(g)
Which reactant is the limiting reactant?
C2H5OH
What is the molecular formula for heptane?
C7H16
If the molar mass is 144 g/mol what is the molecular formula?
C8H16O2
Write a balanced chemical equation for the reaction that occurs when the hydrocarbon styrene, C8H8(l), is combusted in air.
C8H8(l)+10O2(g)→8CO2(g)+4H2O(g)
What products form in this reaction?
CO2,H2O
The element that has a valence configuration of 4s2 is ________.
Ca
Which element does X represent in the following expression: 41/20X?
Ca
Calcium hydride reacts with water to form calcium hydroxide (aqueous) and hydrogen gas Write a balanced chemical equation for the reaction. Express your answer as a balanced chemical equation.
CaH2(s)+2H2O(l)→Ca(OH)2(aq)+2H2(g)
If F is a reactive nonmetal, which other element or elements shown here do you expect to also be a reactive nonmetal?
Cl
Which of the following is a statement of the first law of thermodynamics? q
Energy lost by the system must be gained by the surroundings.
Of the following, ΔH°f is not zero for ________.
F2 (s)
Which of the following are weak electrolytes? HNO3 HF NH3 LiBr
HF, NH3
In the following list, only ________ is not an example of matter.
Heat
For a mixture, indicate whether it is homogeneous or heterogeneous.
Homo - seawater herero - rice pudding
Which statement describes a physical change?
Liquid water evaporates.
Write a balanced chemical equation for the reaction that occurs when Mg(s) reacts with Cl2(g).
Mg(s)+Cl2(g)→MgCl2(s)
Magnesium and sulfur form an ionic compound with the formula ________.
MgS
Which one of the following has the element name and symbol correctly matched?
N, nickel S, silicon ---->>>>> Li, lithium C, copper None of the symbols are correctly matched to the element name.
Which of the following reactions is possible according to Dalton's atomic theory?
N2+O2→2NO
Which of these changes are physical and which are chemical?
Physical - water vapor in the air forms frost. A goldsmith melts gold and pulls into wire. Chemical - plants make sure from Co2 and h2o
What number would you use to convert moles of CH4 to grams of CH4?
The molar mass, 16.0 g/mol.
An experiment requires 46.0 g of ethylene glycol, a liquid whose density is 1.114 g/mL. Rather than weigh the sample on a balance, a chemist chooses to dispense the liquid using a graduated cylinder. What volume of the liquid should he use?
V = 41.3 mL
Atoms of Sg are very unstable, and it is therefore difficult to study this element's properties. Based on the position of Sg in the periodic table, what element should it most closely resemble in its chemical properties?
W
Which set is more precise?
both
Of the following, ________ radiation has the shortest wavelength.
X-RAY
Elements in Group 2A are known as the ________.
alkaline earth metals
What is the systematic name of NH4ClO3?
ammonium chlorate
What is the correct name for the compound NH4ClO4?
ammonium perchlorate
What isotope has 18 protons and 22 neutrons?
argon-40
A sulfur oxide is 50.0% by mass sulfur. This molecular formula could be ________.
either SO2 or S2O4
Cathode rays are ________.
electrons
Precision refers to ________.
how close a measured number is to other measured numbers
Which one of the choices below is not considered a fossil fuel?
hydrogen
Gases and liquids share the property of ________.
indefinite shape
What is the systematic name of PbO?
lead(II) oxide
MnO2
manganese(IV) oxide
How many protons, electrons, and neutrons are in an 266Sg atom?
p, e, n = 106,106,160
Which electron configuration represents a violation of Hund's rule for an atom in its ground state?
up down, up down, up down
Which one of the following is the correct electron configuration for a ground-state nitrogen atom?
up down, up down, up up up
If no magnetic field were applied, would you expect the electron beam to be deflected upward or downward by the electric field?
downward
How many different principal quantum numbers can be found in the ground-state electron configuration of nickel?
4
Nitrogen (N2) and hydrogen (H2) react to form ammonia (NH3). Consider the mixture of N2 and H2 shown in the accompanying diagram. The blue spheres represent N, and the white ones represent H. (Figure 1)
limiting reactant H2
NiO
nickel(II) oxide
The quantity 1.0 mg/cm2 is the same as 1.0 × ________ kg/m2.
10^-2
An atom has a mass number of 27 and 14 neutrons. What is the atomic number of this atom?
13
Given the following reactions N2 (g) + 2O2 (g) → 2NO2 (g) ΔH = 66.4 kJ 2NO (g) + O2 (g) → 2NO2 (g) ΔH = -114.2 kJ the enthalpy of the reaction of the nitrogen to produce nitric oxide N2 (g) + O2 (g) → 2NO (g)
180.6
Now that we have put coefficients of 3 in front of CaSO4 and CaCl2, what coefficient should go in front of AlCl3 to balance both the Cl atoms and the Al atoms? 3CaSO4+?AlCl3→3CaCl2+Al2(SO4)3
2
When the following equation is balanced, the coefficient of H2O is ________. Ca (s) + H2O (l) → Ca(OH)2 (aq) + H2 (g)
2
The specific heat capacity of solid copper metal is 0.385 J/g-K. How many joules of heat are needed to raise the temperature of a 1.15-kg block of copper from 25.0 °C to 77.5 °C?
2.32 × 104 J
Calculate the average value of the absolute deviations of each measurement from the average for the second set.
2x10^-2
Now that we have put a coefficient of 3 in front of CaSO4, what coefficient should go in front of CaCl2 to balance calcium (Ca)? 3CaSO4+AlCl3→?CaCl2+Al2(SO4)3
3
There are ________ unpaired electrons in a ground state nitrogen atom.
3
Write the balanced equation for the reaction that occurs when methanol, CH3OH (l), is burned in air. What is the coefficient of oxygen in the balanced equation?
3
601 kg Express your answer as an integer.
3 sigfigs
An electron cannot have the quantum numbers n = ________, l = ________, ml= ________.
3,2,3
Electromagnetic radiation travels through vacuum at a speed of ________ m/s.
3.00 × 108
2.03 g of C4H10 reacts with 7.28 g of O2 to form 6.16 g of CO2. Using only addition and subtraction, calculate the amount of H2O produced.
3.15 g
The output of a plant is 4335 pounds of ball bearings per week (five days). If each ball bearing weighs 0.0113 g, how many ball bearings does the plant make in a single day? (Indicate the number in proper scientific notation with the appropriate number of significant figures.)
3.48 x 10^7
A metal object has a mass of 1.6 × 106 mg. What is this mass expressed in pounds?
3.5 lb
[Ar]4s23d104p3 is the electron configuration of a(n) ________ atom.
As
What is the empirical formula for valproic acid?
C4H8O
How many grams of aluminum hydroxide are obtained from 16.2 g of aluminum sulfide?
16.8 g
When the following equation is balanced, the coefficients are ________. Al(NO3)3 + Na2S → Al2S3 + NaNO3
2, 3, 1, 6
Which two of the following are isotopes of the same element:31/16X,31/15X,32/16X,?
31/16, 32/16
What are the spectator ions in the reaction between KOH (aq) and HNO3 (aq)?
K+ and NO3-
Which of the following compounds would you expect to be ionic?
KCl
What is the name of the covalent compound N2O5?
dinitrogen pentoxide
What is the probable identity of the substance?
toluene
A neutralization reaction between an acid and a metal hydroxide produces ________.
water and a salt
If you had excess aluminum, how many moles of aluminum chloride could be produced from 15.0 g of chlorine gas, Cl2?
0.141 mol
Bamboo can grow up to 60.0 cm/day. Convert this growth rate into inches per hour. Express your answer to three significant figures and include the appropriate units.
0.984 in/h
When the following equation is balanced, the coefficient of water is ________. N2O5 (g) + H2O (l) → HNO3 (aq)
1
What is the sum of the coefficients in the balanced chemical equation for the combustion of acetone, C3H6O(l), in air?
11
There are ________ mol of carbon atoms in 4 mol of C4H8O2.
16
In which one of the following numbers are none of the zeros significant?
161.00 901 ---->>> 0.006 100.00 0.00050
The compound responsible for the characteristic smell of garlic is allicin, C6H10OS2. The mass of 1.00 mol of allicin, rounded to the nearest integer, is ________ g.
162
The atomic number of fluorine is 9. What is the mass number of a fluorine atom with 8 neutrons? Express your answer as an integer.
17
Write the balanced equation for the reaction that occurs when methanol, CH3OH (l), is burned in air. What is the coefficient of methanol in the balanced equation?
2
0.054 s Express your answer as an integer.
2 sigfigs
Perform the following calculation and choose the answer with the correct significant figures. (164.2 + 40.53)/0.098
2.1 × 10^3
The element X has three naturally occurring isotopes. The masses (amu) and % abundances of the isotopes are given in the table below. The average atomic mass of the element is ________ amu. Isotope abund mass 221x 82.900 220.90 220x 13.200 220.00 218x 3.9000 218.10
220.67
Specify the number of protons, neutrons, and electrons in the neutral atom copper-64.
29,35,29 protons, neutrons, electrons
How many bottles are left over?
2x10^4
0.0105 L Express your answer as an integer.
3 sig figs
Aluminum forms an ion with a charge of ________.
3+
The molarity (M) of an aqueous solution containing 22.5 g of glucose (C6H12O6) in 35.5 mL of solution is ________.
3.52
Calculate the kinetic energy in joules of an 80.0 g bullet traveling at 300.0 m/s.
3.60 × 103 J
Which one of the following is the highest temperature?
302 K 96 °F ----> 38 °C <------ none of the above the freezing point of water
The formula weight of lead nitrate (Pb(NO3)2) is ________ amu.
331.2
Give the nuclear symbol for the isotope of argon for which A=38?
38/18Ar
How many molecules of CO2, H2O, C2H5OH, and O2 will be present if the reaction goes to completion?
4,6,0,1 molecule
What is the percentage of oxygen, by mass, in calcium phosphate?
41.3
6.3050 cm Express your answer as an integer.
5 sigfigs
Sulfur and fluorine react in a combination reaction to produce sulfur hexafluoride: S (s) + 3F2(g) → SF6 (g) The maximum amount of SF6 that can be produced from the reaction of 3.5 g of sulfur with 4.5 g of fluorine is ________ g.
5.8
The atomic number of an atom of 130Xe is ________.
54
Given the following reactions H2O (l) → H2O (g) ΔH = 44.01 kJ 2H2 (g) + O2 (g) → 2H2O (g) ΔH = -483.64 kJ the enthalpy for the decomposition of liquid water into gaseous hydrogen and oxygen 2H2O (l) → 2H2 (g) + O2 (g) is ________ kJ.
571.66
Each p-subshell can accommodate a maximum of ________ electrons.
6
What mass (g) of barium iodide is contained in 313mL of a barium iodide solution that has an iodide ion concentration of 0.110M?
6.73
In a titration of 35.00 mL of 0.737 M H2SO4, ________ mL of a 0.827 M KOH solution is required for neutralization.
62.4
The molecular formula mass of this compound is 240 amu . What are the subscripts in the actual molecular formula? Enter the subscripts for C, H, and O,
8,16,8
The de Broglie wavelength of an electron is 8.7 × 10-11 m. The mass of an electron is 9.1 × 10-31 kg. The velocity of this electron is ________ m/s.
8.4 × 106
A temperature of 300. K is the same as ________ °F.
81
The British thermal unit (Btu) is commonly used in engineering applications. A Btu is defined as the amount of heat required to raise the temperature of 1 lb of water by 1 °F. There are ________ Btu in one Joule. 1 lb = 453.59 g; °C = (5/9)(°F - 32°); specific heat of H2O (l) = 4.184 J/g-K.
9.278 × 10-4 Btu
What number would you use to convert number of molecules of CH4 to moles of CH4?
Avogadro's number, 6.02×1023/1 mol
The spectator ions in the reaction between aqueous perchloric acid and aqueous barium hydroxide are ________.
ClO4- and Ba2+
The law of constant composition applies to ________.
Compounds
Which compound contains the largest amount of anions?
CrF4
Which of the following is an oxidation-reduction reaction?
Cu (s) + 2AgNO3 (aq) → 2Ag (s) + Cu(NO3)2 (aq)
Which one of the following compounds is copper(I) chloride?
CuCl
The proper formula for the hydronium ion is ________.
H3O+
If compound A has an equal number of oxygen and carbon atoms, what can we conclude about the composition of compound B?
It has twice as many oxygen than carbon atoms.
You are given two clear solutions of the same unknown monoprotic acid, but with different concentrations. Which statement is true?
It would take more base solution (per milliliter of the unknown solution) to neutralize the more concentrated solution.
The units of heat capacity are ________.
J/K or J/°C
Which calculation clearly shows a conversion between temperatures in degrees Celsius, °C, and temperature in Kelvins, K?
K = °C + 273.15
Compound Mass N Mass O A 5.6 3.2 B 3.5 8.0 C 1.4 4.0 If you were John Dalton and had never heard of a mole, which of the following would you think were possible sets of formulas for the compounds A, B, and C, respectively?
N2O, N2O4, N2O5
Of the reactions below, which one is a decomposition reaction?
NH4Cl → NH3 + HCl
The formula of a salt is XCl2. The X-ion in this salt has 26 electrons. The metal X is ________.
Ni
When aqueous solutions of ________ are mixed, a precipitate forms.
NiBr2 and AgNO3
The atomic weight of copper, Cu, is listed as 63.546. Which of the following statements are untrue:
Not all neutral atoms of copper have the same number of electrons. The dominant isotopes of Cu must be 63Cu and 64Cu.
When a compound containing C, H, and O is completely combusted in air, what reactant besides the hydrocarbon is involved in the reaction?
O2 (g)
________ and ________ reside in the atomic nucleus.
Protons, neutrons
Which of the following is a molecular compound?
SF4
Of the following, ΔH°f is not zero for ________.
Sc (g)
Cr2O3
chromium(III) oxide
The energy of a photon of light is ________ proportional to its frequency and ________ proportional to its wavelength.
directly, inversely
Physical properties can be classified as either intensive properties or extensive properties. An intensive property is independent of the amount of the sample. An extensive property varies with the amount of the sample.
intensive - matte grey begins to melt at " " has density of 23834 Extensive - has volume of 3.28 Ml Has mass of 44.89 g
In the symbol below, x is ________. x6C
mass number
Potassium is a ________ and chlorine is a ________.
metal, nonmetal
For which one of the following reactions is the value of ΔH°rxn equal to ΔH°f for the product?
none of the above
Classify each of the following as a pure substance or a mixture.
pure substance - magnesium, crushed ice. Mixture - rice pudding, seawater
The valence shell of the element X contains 2 electrons in a 5s subshell. Below that shell, element X has a partially filled 4d subshell. What type of element is X?
transition metal
There are two different compounds of sulfur and fluorine. In SF6, the mass of fluorine per gram of sulfur is 3.55 g F/g S. In the other compound, SFX, the mass of fluorine per gram of sulfur is 1.18 g F/g S. What is the value of X for the second compound?
x = 2
What is the calculated density of the substance?
ρ = 0.86 g/mL
Aqueous solutions of a compound did not form precipitates with Cl-, Br-, I-, SO42-, CO32-, PO43-, OH-, or S2-. This highly water-soluble compound produced the foul-smelling gas H2S when the solution was acidified. This compound is ________.
(NH4)2S
Rutherford's α-scattering experiment. When α particles pass through a gold foil, most pass through undeflected but some are scattered, a few at very large angles. According to the plum-pudding model of the atom, the particles should experience only very minor deflections. The nuclear model of the atom explains why a few α particles are deflected at large angles. For clarity, the nuclear atom is shown here as a colored sphere, but most of the space around the nucleus is empty except for the tiny electrons moving around.
+2
Assuming that the compounds are ionic, what charge is associated with the metallic element in each case? Express your answers as signed integers separated by commas. For example: +1,+2,+3.
+2,+4,+3,+6
Given the data in the table below, ΔH°rxn for the reaction Ca(OH)2 + 2H3AsO4 → Ca(H2AsO4)2 + 2H2O is ________ kJ.
-130.4
Given the data in the table below, ΔH°rxn for the reaction Ag2O (s) + H2S (g) → Ag2S (s) + H2O (l) is ________ kJ.
-267
The change in the internal energy of a system that absorbs 2,500 J of heat and that does 7,655 J of work on the surroundings is ________ J.
-5,155
How many moles of magnesium oxide are produced by the reaction of 3.82 g of magnesium nitride with 7.73 g of water?
.114
How many caps are left over?
0
"Absolute zero" refers to ________.
0 kelvin
How many moles of magnesium oxide are produced by the reaction of 3.82 g of magnesium nitride with 7.73 g of water? Mg3N2 + 3H2O → 2NH3 + 3MgO
0.114
Aluminum reacts with chlorine gas to form aluminum chloride via the following reaction: 2Al(s)+3Cl2(g)→2AlCl3(s) You are given 10.0 g of aluminum and 15.0 g of chlorine gas.
0.371 mol
The molarity of a solution prepared by diluting 43.72 mL of 5.005 M aqueous K2Cr2O7 to 500. mL is ________.
0.438
The freezing point of water at 1 atm pressure is ________.
0c
When the following equation is balanced, the coefficient of H3PO4 is ________. H3PO4 (aq) + NaOH (aq) → Na3PO4 (aq) + H2O (l)
1
A tenfold dilution of a sample solution can be obtained by taking ________.
1 part sample and 9 parts solvent
400 g
1 sig fig
What are the subscripts in the empirical formula of this compound?Enter the subscripts for C, H, and O,
1,2,1
Fluorine forms an ion with a charge of ________.
1-
A bottling plant has 1.26349×105 bottles with a capacity of 355 mL, 1.08565×105 caps, and 4.8750×104 L of beverage. How many bottles can be filled and capped?
1.08565×105 bottles
Based on the first and fourth sketches (Figure 4) , what is the density of the block?
1.12 gcm3
Based on the first and third sketches (Figure 3) , what is the density of the block? Assume that the block is 40.0% submerged.
1.16 g/cm^3
If a soft-drink bottle whose volume is 1.30 L is completely filled with water and then frozen to -10 ∘C, what volume does the ice occupy?
1.41 l
What is the maximum amount in grams of SO3 that can be produced by the reaction of 1.0 g of S with 1.0 g of O2 via the equation below? S (s) + O2(g) → SO3 (g) (not balanced)
1.7
The average fuel value of sugars is 17 kJ/g. A 2.0 L pitcher of sweetened Kool-Aid® contains 400 g of sugar. What is the fuel value (in kJ) of a 500 mL serving of Kool-Aid®? (Assume that the sugar is the only fuel source.)
1.7 × 103 kJ
The density of a 167.4 g sample of magnesium having a volume of 96.32 mL is ________ g/cm3.
1.738
What are the respective concentrations (M) of Cu2+ and Cl- afforded by dissolving 0.921mol CuCl2 in water and diluting to 485mL?
1.90 and 3.80
The lung capacity of the blue whale is 4900 L . Convert this volume into gallons.
1300 gal
Which pair of atoms constitutes a pair of isotopes of the same element?
14/6 X 12/6
What is the maximum number of moles H2 that can be produced by the reaction of 3.00 mol of Ni with 4.50 mol of HCl according to the equation: Ni + 2HCl → NiCl2 + H2
2.25 mol
Round the following number to four significant figures and express the result in standard exponential notation: 229.613
2.296 × 10^2
The energy of a photon that has a wavelength of 8.33 × 10-6 m is ________ J.
2.39 × 10-20
A cubic piece of metal measures 3.00 cm on each edge. If the metal is nickel, whose density is 8.90 g/cm3, what is the mass of the cube?
240 g
What volume (mL) of a concentrated solution of sodium hydroxide (6.00 M) must be diluted to 200.0 mL to make a 0.880 M solution of sodium hydroxide?
29.3
The temperature of a 23 g sample of gold increases from 22.3°C to 32.2°C. If the specific heat of gold is 0.129 J/g-K, how many joules of heat are absorbed?
29.4 J
Notice that "SO4" appears in two different places in this chemical equation. SO 2−4 is a polyatomic ion called "sulfate." What number should be placed in front of CaSO4 to give the same total number of sulfate ions on each side of the equation? ?CaSO4+AlCl3→CaCl2+Al2(SO4)3
3
At what speed (m/s) must a 3.0-mg object be moving in order to have a de Broglie wavelength of 5.4 × 10-29 m?
4.1 m/s
Electromagnetic radiation with a wavelength of 640 nm appears as orange light to the human eye. The frequency of this light is ________ s-1.
4.688 × 10^14
The wavelength of light emitted from a traffic light having a frequency of 7.33×1014 Hz is ________ nm.
409
The Statue of Liberty is 151 ft tall. Calculate its height in meters. Express your answer to three significant figures and include the appropriate units.
46.0 m
7.0500×10 − 3m3. Express your answer as an integer.
5 sig figs
Which number has four significant figures?
5,000,625 --->>>> 25.00 1.1 × 103 0.0001
How many oxygen atoms are contained in 2.74 g of Al2(SO4)3?
5.79 × 10^22
A bumblebee flies with a ground speed of 15.3 m/s . Calculate its speed in km/h. Express your answer to three significant figures and include the appropriate units.
55.1 km/h
Which of the following stoichiometric factors would be used to convert from moles of NH3 to moles of H2O for the reaction: 4NH3 + 5O2 → 4NO + 6H2O
6 mol H2O/4 mol NH3
How many nitrogen atoms are in 10.2 g of copper(II) nitrate?
6.56 × 1022 atoms
Given the following reactions 2NO → N2 + O2 ΔH = -180 kJ 2NO + O2 → 2NO2 ΔH = -112 kJ the enthalpy of the reaction of nitrogen with oxygen to produce nitrogen dioxide N2 + 2O2 → 2NO2 is ________ kJ.
68
The largest principal quantum number in the ground state electron configuration of francium is ________.
7
The ion O2− has _____ protons and _____ electrons.
8, 10
Write a balanced chemical equation for the reaction that occurs when barium carbonate decomposes into barium oxide and carbon dioxide gas when heated.
BaCO3(s)→BaO(s)+CO2(g)
The accompanying sketches suggest four observations made on a small block of plastic material. When analyzing Figure 4, it is helpful to keep in mind that the apparent mass of an object in fluid is equal to its mass in air, minus the mass of the fluid displaced mapparent=mair−mdisplaced fluid
Based on the experiments shown in the first two sketches, (Figure 1) and (Figure 2) , which of the following are valid conclusions? mass is 50g, insoluble in ethanol, density of block greater than .7896 liquid level of beaker is now greater.
Consider the mixture of ethanol, C2H5OH, and O2 shown in the accompanying diagram. Write a balanced equation for the combustion reaction that occurs between ethanol and oxygen.
C2H5OH+3O2→2CO2+3H2O
Write a balanced chemical equation for the reaction that occurs when dimethylether, CH3OCH3(g), is combusted in air.
C2H6O(g)+3O2(g)→2CO2(g)+3H2O(g)
Which of the following is soluble in water at 25∘C?
Fe(NO3)2
A compound contains 38.7% K, 13.9% N, and 47.4% O by mass. What is the empirical formula of the compound?
KNO3
the balanced reaction between aqueous potassium hydroxide and aqueous acetic acid is ________.
KOH (aq) + HC2H3O2 (aq) → H2O (l) + KC2H3O2 (aq)
Combining aqueous solutions of BaI2 and Na2SO4 affords a precipitate of BaSO4. Which ions are spectator ions in the reaction?
Na+ and I-
What is the identity of the element whose isotopes you have selected?
S
Millikan's oil-drop experiment to measure the charge of the electron. Small drops of oil are allowed to fall between electrically charged plates. The drops pick up extra electrons as a result of irradiation by X-rays and so became negatively charged. Millikan measured how varying the voltage between the plates affected the rate of fall. From these data he calculated the negative charge on the drops. Because the charge on any drop was always some integral multiple of 1.602×10−19C, Millikan deduced this value to be the charge of a single electron. Would the masses of the oil drops be changed significantly by any electrons that accumulate on them?
The masses of the oil drops cannot be changed significantly by any electrons that accumulate on them.
What is the molecular formula for octane?
c8h18
Which component limits the production?
caps
What is the name of the covalent compound CCl4?
carbon tetrachloride
Tell which set is the more accurate based on the average.
first
Compound A contains 1.333 g of oxygen per gram of carbon, whereas compound B contains 2.666 g of oxygen per gram of carbon. What chemical law do these data illustrate?
law of multiple proportions
How many grams of calcium hydride are needed to form 4.650 g of hydrogen gas?
m = 48.94 g
A common English set of units for expressing velocity is miles/hour. The SI unit for velocity is ________.
m/s
What is the systematic name of Mg(NO3)2?
magnesium nitrate
You are given a sample resembling silver. Which of the following properties could be used to help determine whether the sample is really silver?
melting and density point
Can the ice be contained within the bottle?
no
Could the empirical formula determined from chemical analysis be used to tell the difference between acetylene, C2H2, and benzene, C6H6?
no
A 0.100 M solution of ________ will contain the highest concentration of potassium ions.
potassium phosphate
All of the orbitals in a given electron shell have the same value as the ________ quantum number.
principal
Which subatomic particle(s) are found in the nucleus of the atom?
protons, neutrons
The formula weight of a substance is ________.
the sum of the atomic weights of each atom in its chemical formula
When a hydrocarbon burns in air, a component produced is ________.
water
