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Question
Convert 0.490 ng to milligrams and express the answer in scientific notation using the correct number of significant figures.
A.4.90 10-5 mg
B.4.90 10-7 mg
C.4.9 10-mg
D.0.490 10-8 mg
E.0.490 10-7 mg
Answer
This answer is hidden. It contains 2 characters.
Related questions
Q:
Hydrogen peroxide decomposes into water and oxygen in a first-order process.
H2O2(aq) H2O() + 1/2 O2(g)
At 20.0 C, the half-life for the reaction is 3.92 104 seconds. If the initial concentration of hydrogen peroxide is 0.52 M, what is the concentration after 7.00 days?
A.1.2 10-5 M
B.0.034 M
C.0.074 M
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E.0.52 M
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B.x axis = ln[time], y axis = [A]
C.x axis = ln[time], y axis = [A]
D.x axis = time, y axis = 1/[A]
E.x axis = 1/time, y axis = 1/[A]
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________ are colloidal dispersions of one liquid in another liquid.
Q:
Aqueous colloidal solutions can be classified as ________ (water-fearing), or hydrophilic (water-loving).
Q:
A(n) ____ is a colloidal dispersion of a solid in a liquid.
A.gel
B.emulsion
C.aerosol
D.foam
E.sol
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At 25 C, what is the osmotic pressure of a homogeneous solution consisting of 21.0 g urea (CON2H4) diluted with water to 2.50 L? (R = 0.08206 Latm/molK)
A.0.205 atm
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Q:
Which of the following statements concerning osmosis is/are CORRECT?
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2/ Solvents move from regions of low solute concentration to regions of higher solute concentration.
3/ Osmotic pressure is a colligative property.
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E.1, 2, and 3
Q:
What is the boiling point of a solution containing 0.852 g naphthalene(C10H8, molar mass = 128.2 g/mol) dissolved in 14.0 g benzene? The boiling point of pure benzene is 80.10 C and the boiling point elevation constant, Kbp, is 2.53 C/m.
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B.80.25 C
C.81.30 C
D.82.50 C
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Q:
Assuming ideal behavior, which of the following aqueous solutions should have the highest boiling point?
A.1.00 m LiBr
B.0.75 m K2SO4
C.0.50 m Ca(NO3)2
D.0.75 m NaCl
E.1.25 m C6H12O6
Q:
The Henry's law constant for O2 in water at 25 C is 1.3 10-3 mol/kgbar. What partial pressure of O2 (in atm) is necessary to achieve an equilibrium concentration of 2.9 10-3 mol/kg O2? (1 atm = 0.9869 bar)A.0.44 atmB.0.45 atmC.2.1 atmD.2.3 atmE.3.8 atm
Q:
Which of the following statements concerning solubility is/are CORRECT?
1/ Ionic compounds composed of Group 1A metal ions and halide ions, such as NaCl, are insoluble in nonpolar solvents.
2/ The solubility of the halogens (Cl2, Br2, and I2) in polar solvents is greater than their solubility in nonpolar solvents.
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Q:
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Q:
If the molality of a NaBr(aq) solution is 2.50 m, what is the weight percent of NaBr? The molar mass of NaBr is 102.9 g/mol.
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B.25.0%
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Q:
What is the definition of molality?
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B.grams of solute per kg of solution
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Q:
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Q:
Which of the following statements is/are CORRECT? If an ionic compound with the formula MX forms a face-centered cubic unit cell with the anions (Xn-) at the lattice points, the cations (Mn+) may occupy1/ one fourth of the tetrahedral holes in each unit cell.2/ all of the octahedral holes in each unit cell.3/ the center of each face in each unit cell.A.1 onlyB.2 onlyC.3 onlyD.1 and 2E.1, 2, and 3
Q:
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C.6
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Q:
What is the distance, in atomic radii, along any edge of a body-centered unit cell?
A.
B.2 r
C.4 r
D.
E.r
Q:
If a metal crystallizes in a primitive cubic lattice, each metal atom has ____ "nearest neighbors."
A.3
B.4
C.6
D.8
E.12
Q:
If a metal crystallizes in a face-centered cubic lattice, each metal atom has ____ "nearest neighbors."
A.3
B.4
C.6
D.8
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Q:
Arrange the three common unit cells in order from least dense to most dense packing.
A.face-centered cubic < body-centered cubic < primitive cubic
B.primitive cubic < body-centered cubic < face-centered cubic
C.primitive cubic < face-centered cubic < body-centered cubic
D.body-centered cubic < primitive cubic < face-centered cubic
E.body-centered cubic < face-centered cubic < primitive cubic
Q:
Which equation represents the number of atoms in a body-centered cubic unit cell?
A.
B.
C.
D.
E.
Q:
The solubility product equilibrium constant, Ksp, of silver bromide is 5.4 10-13 at 298 K.
AgBr(s) Ag+(aq) + Br-(aq)
What is DrG? (R = 8.314 J/Kmol)
A.-3.0 101 kJ/mol
B.-5.87 kJ/mol
C.5.87 kJ/mol
D.3.0 101 kJ/mol
E.7.0 101 kJ/mol
Q:
What is the equilibrium constant for reaction below at 25 C? (R = 8.314 J/Kmol)2 NO(g) + O2(g) 2 NO2(g)given DfG [NO(g)] = +86.6 kJ/mol and DfG [NO2(g)] = +51.2 kJ/mol.A.3.9 10-13B.1.0C.2.6 1012D.1.6 106E.3.8 1028
Q:
All of the following relationships are true EXCEPT
A..
B..
C..
D..
E..
Q:
Calculate DrG for the combustion of benzene at 325 K.2 C6H6() + 15 O2(g) 12 CO2(g) + 6 H2O()Species DfH (kJ/mol) S (J/Kmol)C6H6() 49.0 173.3O2(g) 0 205.1CO2(g) -393.5 213.7H2O() -285.8 67.0A.-6386 kJ/mol-rxnB.-6078 kJ/mol-rxnC.-7251 kJ/mol-rxnD.-8611 kJ/mol-rxnE.+1431 kJ/mol-rxn
Q:
If a chemical reaction is exothermic, but not spontaneous, which of the following must be true?
A.DrG > 0, DrS > 0 and DrH > 0
B.DrG < 0, DrS > 0 and DrH > 0
C.DrG > 0, DrS < 0 and DrH > 0
D.DrG < 0, DrS < 0 and DrH < 0
E.DrG > 0, DrS < 0 and DrH < 0