You have the following solutions at your disposal to prepare a buffer solution with a pH greater than 7.0:
(1) 50.0 mL of 0.35 M NH3 Kb = 1.8×10-5 (2) 55.0 mL of 0.35 M NaOH
(3) 50.0 mL of 0.35 M HCl (4) 16.5 mL of 0.35 M NaCl NaOH
(5) 16.5 mL of 0.35 M HNO3 (6) 16.5 mL of 0.35 M KOH
(a) Assuming that you are going to mix the entire quantity of the listed solutions to prepare the buffer, which two solutions would you use?
In: Chemistry
Given the provided enthalpies of formation, calculate ΔH for the reaction shown.
2 H2 (g) + O2 (g) → 2 H2O (g) ΔH = -483.6 kJ
3 O2 (g) → 2 O3 (g) ΔH = +285.4 kJ
6 H2 (g) + 2 O3 (g) → 6 H2O (g) ΔH = ?
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When 25.00 mL of unknown were passed through a Jones reductor, molybdate ion (MoO42-) was converted into Mo3+. The filtrate required 16.43 mL of 0.01033 M KMnO4 to reach the purple end point.
MnO4- + Mo3+ → Mn2+ + MoO22+
A blank required 0.01 mL. Balance the reaction. (Use the lowest possible coefficients. Omit states-of-matter.)
Find the molarity of molybdate in the unknown.
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A beaker with 125 mL of an acetic acid buffer with a pH of 5.000 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.100 M. A student adds 7.00 mL of a 0.360 M HCl solution to the beaker. How much will the pH change? The pKa of acetic acid is 4.740.
In: Chemistry
iron nail and copper (II) sulfate the compound contains Fe2+
molecular equation
ionic equation
net ionic equation
spectator ions
In: Chemistry
3Mg +2AlCl3 -------> 2Al +3MgCl2
a)calculate the mass of aluminium chloride that will react with 40g
of magnesium.
b) calculate the mass of each product formed from the reaction of 40g of mg
2)when propane gas C3H8 is burned with oxygen 50g of water is collected.what mass of propane was burned?
3)metallic iron can be produced by reacting iron(iii) oxide with carbon as shown below.when 100g of iron(iii)oxide is reacted, 45g of iron metal is obtained.what is the percent yield of the reaction?
In: Chemistry
current event or recent research related to atoms,atomic structure or chemical bonds.
In: Chemistry
1. A soil has the following cations reported as cmolc per kg of soil Ca = 6; Mg = 4; K = 3; Na = 2; Al3+ = 10.
a. Calculate the CEC of the soil (cmolc per kg) ( 1 point)
b. Calculate the base saturation (2 points)
c. How much CaCO3 needs to be added to this soil to raise the base saturation to 80%? (3 points)
d. How much CaO needs to be added to this soil to raise the base saturation to 80%? (4 points)
In: Chemistry
A mixture of methane (CH4) and ethane (C2H6) is stored in a container at 294 mm Hg. The gases are burned in air to form CO2 and H2O. If the pressure of CO2 is 346 mm Hg measured at the same temperature and volume as the original mixture, calculate the mole fraction of the gases.
Mole fraction of methane: _____________
Mole fraction of ethane: _________________
In: Chemistry
Write a balanced net ionic equation for the reaction of manganese(II) hydroxide, Mn(OH)2, with hydrochloric acid.
|
Mn(OH)2(s) + 2H+(aq) ---> Mn2+(aq) + 2H2O(l) |
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Mn(OH)2(s) + 2H+(aq) ---> MnH2(s) + 2OH−(aq) |
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(OH)3(aq) + 3H+(aq) ---> 3H2O(l) |
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3OH−(aq) + 3H+(aq) ---> 3H2O(l) |
||
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Mn2+(aq) + 2Cl−(aq) ---> MnCl2(aq) |
In: Chemistry
Question:1
You dissolve 312 mg of a compound
(AwBxCyDz) in water
producing 14.31 mL of solution and use the photometer and standard
solutions to find that the concentration of the A is 1.24 x
10-2 M. The molar mass of A is 114.52 g/mol.
Moles of A in the solution sample:________________________________
Mass of A in the solution sample: _________________________________
Mass % of A in the compound: _______________________________
Moles of A in 100 grams of the compound:
________________________________
Question:2
The compound, AwBxCy, like all
compounds has an oxidation number of 0 (zero). The oxidation number
of A is +1, the oxidation number of B is +2, and the oxidation
number of C is –1. If there are two moles of A for every 3 moles of
C in one mole of the compound, what is the empirical formula of the
compound?
Question:3
Given the compound,
KwAlx(SO4)y(H2O)z.
100.00 grams of the compound contains 8.24 grams of potassium and
5.69 grams of aluminum. What is the formula of the compound?
In: Chemistry
1. Retention time (tR) is a measure of how long a compound is retained on a stationaryphase in column in column chromatography. In TLC, Rf was a measure of how long thecompound was retained on the stationary phase. What is the relationship between tR and Rf?
2. What would be the order of elution if one separated the pigments of spinach on columnchromatography?
3. What if any would you have to change in terms of the mobile phase if you wanted toactually perform the column chromatography in order to separate the pigments of spinachcompare to the one used for the TLC Experiment? Explain.
4. Why is it important to keep the solvent level above the stationary phase? What wouldhappen if one lets the solvent get much lower than the alumina stationary phase?
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Discuss the relationship between a gas chromatogram and mass spectrometry data. How do they correspond to identify the compounds present?
In: Chemistry
N, N'-Dimethylformamide (DMF) is a commonly-used polar solvent. Its normal boiling point is 426K and is has ΔH°vap = 47.6 kJ/mol. Suppose a laboratory vacuum system is able to maintain a flask at total pressure of 5.0 Torr. Estimate the temperature at which DMF will boil in this flask.
Please show all work.
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