1-\Naturally occurring copper exists in two isotopic forms: 63Cu and65Cu. The atomic mass of copper is 63.55 amu. What is the approximate natural abundance of 63Cu?
Select one:
a.
63%
b.
90%
c.
70%
d.
30%
e.
50%
1-\The molar mass of the compound formed by potassium and sulfur is _____.
Select one:
a.
110.3 g/mol
b.
135.3 g/mol
c.
103.2 g/mol
d.
71.2 g/mol
e.
149.4 g/mol
How many oxygen atoms are there in one formula unit of Ca3(PO4)2?
Select one:
a.
none of these
b.
2
c.
4
d.
6
e.
8
What is the molar mass of ethanol (C2H5OH)?
Select one:
a.
34.06 g/mol
b.
46.07 g/mol
c.
105.03 g/mol
d.
45.06 g/mol
e.
30.03 g/mol
How many oxygen atoms are there in 3 formula units of Al(NO3)3?
Select one:
a.
15
b.
9
c.
30
d.
27
e.
14
The molar mass of an insecticide, dibromoethane, is 187.9 g/mol. Its molecular formula is C2H4Br2. What percent by mass of carbon does dibromoethane contain?
Select one:
a.
2.14%
b.
85.05%
c.
6.39%
d.
12.78%
e.
0.536%
What is the molar mass of cryolite (Na3AlF6)?
Select one:
a.
185.3 g/mol
b.
104.2 g/mol
c.
210.0 g/mol
d.
209.9 g/mol
e.
68.97 g/mol
Each molecule of lycopene contains 40 atoms of carbon (plus other atoms). The mass percent of carbon in lycopene is 84.49%. What is the molar mass of lycopene?
Select one:
a.
1137.2 g/mol
b.
568.6 g/mol
c.
480.4 g/mol
d.
405.9 g/mol
e.
473.4 g/mol
Calculate the molar mass of magnesium sulfite.
Select one:
a.
288.83 g/mol
b.
120.38 g/mol
c.
104.38 g/mol
d.
128.69 g/mol
e.
88.38 g/mol
How many atoms of hydrogen are present in 6.43 g of ammonia?
Select one:
a.
2.27 × 1023
b.
9.41 × 1019
c.
1.16 × 1025
d.
6.82 × 1023
e.
1.28 × 1024
A given sample of a xenon fluoride compound contains molecules of a single type XeFn, where n is some whole number. Given that 8.86 × 1020 molecules of XeFn weigh 0.361 g, calculate n.
Select one:
a.
3
b.
2
c.
1
d.
6
e.
4
What would be the g Al / mole S ratio for the product of a reaction between aluminum and sulfur?
Select one:
a.
53.96 g Al / mol S
b.
17.99 g Al / mol S
c.
26.98 g Al / mol S
d.
40.47 g Al / mol S
e.
80.94 g Al / mol S
How many grams of potassium are in 15.0 g of K2CrO7?
Select one:
a.
4.84 g
b.
2.42 g
c.
30.0 g
d.
78.2 g
e.
0.767 g
How many moles of hydrogen sulfide are contained in a 39.3-g sample of this gas?
Select one:
a.
19.5 mol
b.
2.31 mol
c.
0.867 mol
d.
1.15 mol
e.
73.4 mol
Nitric acid, HNO3, contains what percent hydrogen by mass?
Select one:
a.
2.22%
b.
3.25%
c.
20.0%
d.
1.60%
e.
25.4%
The mineral mimetite has the formula Pb5(AsO4)3Cl. What mass percent of oxygen does it contain?
Select one:
a.
12.90 %
b.
38.70 %
c.
50.32 %
d.
1.08 %
e.
16.34 %
Which compound contains the highest percent by mass of hydrogen?
Select one:
a.
H2SO4
b.
HF
c.
H2S
d.
H2O
e.
HCl
A hydrocarbon (a compound consisting solely of carbon and hydrogen) is found to be 85.6% carbon by mass. What is the empirical formula for this compound?
Select one:
a.
C3H
b.
CH4
c.
CH
d.
C2H
e.
CH2
Adipic acid contains 49.32% C, 43.84% O, and 6.85% H by mass. What is the empirical formula?
Select one:
a.
C3HO3
b.
C3H3O4
c.
C2H5O4
d.
C2HO3
e.
C3H5O2
The empirical formula of a group of compounds is CHCl. Lindane, a powerful insecticide, is a member of this group. The molar mass of lindane is 290.8 g/mol. How many atoms of carbon does a molecule of lindane contain?
Select one:
a.
3
b.
8
c.
4
d.
6
e.
2
The empirical formula of styrene is CH; its molar mass is 104.1 g/mol. What is the molecular formula of styrene?
Select one:
a.
C8H8
b.
C6H6
c.
C10H12
d.
C2H4
e.
none of these
A reaction occurs between sodium carbonate and hydrochloric acid producing sodium chloride, carbon dioxide, and water. The correct set of coefficients, respectively, for the balanced reaction is:
Select one:
a.
8 6 5 10 5
b.
3 6 6 3 4
c.
none of these
d.
1 2 2 1 1
e.
5 10 10 5 5
Which of the following equations correctly describes the combustion of CH4 and O2 to produce water (H2O) and carbon dioxide (CO2)?
Select one:
a.
CH4 + O2 → CO2 + H2O
b.
CH4 + 2O2 → CO2 + 2H2O
c.
2CH4 + 3O2 → 2CO2 + 2H2O
d.
CH4 + O2 → CO2 + 2H2O
e.
CH4 + 3O2 → 2CO2 + H2O
Give (in order) the correct coefficients to balance the
following reaction:
H2SnCl6 + H2S → SnS2 +
HCl
Select one:
a.
6, 2, 1, 1
b.
1, 1, 1, 6
c.
1, 2, 1, 6
d.
1, 2, 2, 2
e.
2, 4, 2, 6
How many of the following are true concerning balanced chemical equations?
I. The number of molecules is conserved.
II. The coefficients for the reactants tell you how much of each reactant you are given.
III. Atoms are neither created nor destroyed.
IV. The coefficients indicate the mass ratios of the substances used.
V. The sum of the coefficients on the reactant side equals the sum of the coefficients on the product side.
Select one:
a.
3
b.
1
c.
2
d.
4
e.
5
In: Chemistry
What is the pH at the equivalence point in the titration of a 23.2 mL sample of a 0.376 M aqueous acetic acid solution with a 0.432 M aqueous barium hydroxide solution? pH =
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In the reaction:
Fe^3+ + SCN^− ⇌ [Fe(NCS)]2+
The initial concentration of Fe^3+ was 0.109 and the initial concentration of SCN^− was 0.105. After equilibrium was established, the concentration of the complex was 0.09. What is the equilibrium constant?
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please answer questions 3&4
thanks
Q• Identify components of glycoconjugate structures and classify them based on open and closed forms, conformations and epimeric classes ( CC2)
Q2• Draw mechanisms related to the interconversion of anomeric forms of sugars (CC2)
Q3• Explain the complexity of glycoconjugates and how carbohydrate structures contribute to biological function ( CC2 )
Q4• Compare carbohydrate polymers to protein polymers in terms of structure, stability and biological function. (CC2)
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What are some similarities between transition metal elements and representational metals? (besides both are oxidized by nonmetals)
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This is a two part solution. Please include step by step solution that way I can study from this. Thank you.
Equation (24.2): 3I^-(aq) + H2O2(aq) + 2H3O^+(aq) ---> I3^-(aq) + 4H2O(l)
Equation (24.11): 2 S2O3^2-(aq) + I3^-(aq) ---> 3 I^-(aq) + S4O6^2-(aq)
Part 1:
Add equations 24.2 and 24.11 together.What happens to I-1 and I3-1?
What should happen to their concentrations while S2O3-2 is present?
Inspect equations 24.2 and 24.11 again.
What will happen to the concentration of I3-1 when S2O3-2 is gone?
Part B:
When would the solution turn blue if S2O3-2 was never added to the solution?
When would the solution turn blue if starch was never added to the solution?
Explain your answers.
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need summary on aspects of covalent bonds, violations of the Octet rules and molecular shapes.
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Using a 0.20 M phosphate buffer with a pH of 6.0, you add 0.70 mL of 0.52 M HCl to 58 mL of the buffer. What is the new pH of the solution?
Using a 0.30 M phosphate buffer with a pH of 7.1, you add 0.75 mL of 0.48 M NaOH to 45 mL of the buffer. What is the new pH of the solution?
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Why are carboxylic acids, ketones and esters suitable compounds for analysis by gas chromatography-mass spectrometry (GCMS)
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Hemoglobin and Myoglobin, HOW is oxygen binding regulated? what other mechanisms control oxygen binding in oxygenated vs deoxygenated tissues ( lung v. exercising muscles)?
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The Ksp of Al(OH)3 is 1.0 x 10-33. What is the solubility of Al(OH)3 in 0.0010 M Al(NO3)3? Give your answer using scientific notation and to 2 significant figures (i.e., one decimal place).
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Explain what would happen if the hexane was added to the top of the column immediately after adding the sample. This is for isolation of chlorophyll and carotenoid pigments from spinach
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Calculate the initcial I^- concentration in a solution containing 3.0 mL of 0.20 M KI, 5.0 mL of 0.15 M (NH4)2S2O8, 5.0 mL of 0.25 M (NH4)SO4, 6.0 mL of 0.10 M KNO3, and 1.0 mL of 0.012 M Na2S2O3.
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What is the molarity of a sodium hydroxide solution if 25.0 ml of this solution reacts exactly with 22.30 ml of 0.253 M sulfuric acid?
Thanks!
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Consider the insoluble compound copper(II) hydroxide , Cu(OH)2 . The copper(II) ion also forms a complex with ammonia . Write a balanced net ionic equation to show why the solubility of Cu(OH)2 (s) increases in the presence of ammonia and calculate the equilibrium constant for this reaction. For Cu(NH3)42+ , Kf = 6.8×1012 . Use the pull-down boxes to specify states such as (aq) or (s). + + K =
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