In: Chemistry
A) How many grams of solid sodium
fluoride should be added to 1.00
L of a 0.218 M hydrofluoric acid
solution to prepare a buffer with a pH of 3.847
?
grams sodium fluoride
= g.
B)How many grams of solid sodium
hypochlorite should be added to
0.500 L of a 0.297 M
hypochlorous acid solution to prepare a buffer
with a pH of6.803 ?
grams sodium hypochlorite
= g.
C)How many grams of solid ammonium
chloride should be added to 1.50
L of a 0.152 M ammonia solution
to prepare a buffer with a pH of 8.330
?
grams ammonium chloride
= g.
In: Chemistry
How do you calculate the concentration in ppm from a gas chromatograph? The chromatograph is from a BTEX mixture and shows a peak for each component of the mixture. Bromobenzene was used as an internal standard. How can you calculate the concentration of each component using the ratios of peak area? Is there a specific equation for this?
Thank you!
In: Chemistry
A scientist dilutes 40.0 mL of a pH 5.85 solution of HCl to 1.00 L. What is the pH of the diluted solution (Kw = 1.0 × 10⁻¹⁴)?
In: Chemistry
|
[H3O^+(aq)] |
Drops of Stock Solutions |
Reaction Time |
|||
|
Test Tube |
KMnO4 |
H2O |
H3O^+/H2SO4 |
C2O4H2 |
|
|
C-1 |
15 |
25 |
5 |
5 |
14mins 3 sec |
|
C-2 |
15 |
15 |
15 |
5 |
8mins 10sec |
|
C-3 |
15 |
5 |
25 |
5 |
3mins 8 sec |
a) What are the molecules and ions doing in solution – are they static or moving around?
b) Can ions or molecules that are isolated from one another react? What must happen for them to react?
c) Why should the permanganate disappear faster if the concentration of H3O+(aq) is higher?
d) Devise a general, qualitative, statement about the effect that an increase in the concentration of a reactant has on the rate of a reaction, and an explanation of that effect.
In: Chemistry
Chromium forms cubic crystals whose unit cell has an edge length
of 288.5 pm. The density of the metal is 7.20 g/cm3. The atomic
weight of Cr is 51.996 amu.
a) Calculate the number of atoms in a unit cell, assuming all atoms
are at lattice points.
b) What type of cubic lattice does chromium have?
c) Calculate the radius of the Cr atom.
d) Calculate the empty volume of the cell.
Since I have the edge length, I'm pretty sure I cube that for
volume and convert that to cm. Because I also have the density, I
can use my calculated volume to find the mass. I also know the
equation for this problem involves Avogado's number (6.022x10^-23)
I just don't know how to find the answers to these questions, only
an idea how to begin solving.
Can anyone help? Unfortunately there is no answer key so I can't
even check if I'm right!
In: Chemistry
A solution is made by mixing exactly 500.0 mL of 0.167 M NaOH with exactly 500.0 mL of 0.100 M CH3COOH. Calculate the equilibrium concentrations of H3O+, CH3COOH, CH3COO-, OH-, and Na+.
[H3O+] = M
[CH3COOH] = M
[CH3COO-] = M
[OH-] = M
[Na+] = M
In: Chemistry
In the chemiluminesence reaction, a diene is generated on the luminol molecule. Why does the reaction not progress from that point forward as a Diels-Alder reaction with molecular oxygen acting as the dienophile? How does ground state molecular oxygen exist and does this affect the possibility of a Diels-Alder mechanism with O2?
In: Chemistry
The complex ion Cu(NH3)42 is formed in a solution made of 0.0400 M Cu(NO3)2 and 0.500 M NH3. What are the concentrations of Cu2 , NH3, and Cu(NH3)42 at equilibrium? The formation constant*, Kf, of Cu(NH3)42 is 1.70 × 1013.
In: Chemistry
|
Drops of Stock Solutions |
Temp. (K) |
Reaction Time |
||||
|
Test Tube |
KMnO4 |
H2O |
H3O^+/H2SO4 |
C2O4H2 |
||
|
E-1 |
15 |
15 |
15 |
5 |
278 K |
3 min 1 sec |
|
E-2 |
15 |
15 |
15 |
5 |
300 K |
6 min 13 sec |
a. What effect does the temperature of the solutions have on the rate of the reaction?
b. How does heating the reaction mixture affect the energy of the species in solution? What effect would cooling the reaction mixture have on the energy of the species in solution?
c. Write a general, qualitative, statement about how the rate of a reaction depends on the temperature at which the reaction is carried out.
In: Chemistry
A solution containing 10.00 mL of 0.0500 M metal ion buffered to pH = 10.00 was titrated with 0.0400 M EDTA. Calculate the fraction (αY4-) of free EDTA in the form Y4−. Keep 2 significant figures.
In: Chemistry
A rigid container has water of 2 kg at 120 C with a quality of 25%. The container is heated to the temperature of 140 Celsius, calculate the new quality?
In: Chemistry
HClO is a weak acid (Ka = 4.0 × 10–8) and so the salt NaClO acts as a weak base. What is the pH of a solution that is 0.017 M in NaClO at 25 °C
In: Chemistry
1.For the reaction,
PCl5(g) <-----> PCl3(g) + Cl2(g) Kp = 24.6 at 500 K
calculate the equilibrium partial pressures of the reactants and
products if the initial pressures are PPCl5 =
0.610 atm, PPCl3 = 0.400 atm and
PCl2 = 0.000 atm.
PPCl5 = PPCl3 = PCl2 =
2.
H2O(g) + Cl2O(g) <-----> 2HClO(g) Kc = 0.14 at 298.15 K
calculate the equilibrium concentrations of the reactants and
products if the initial concentrations are [H2O(g)] =
0.00482 mol L-1, [Cl2O(g)] = 0.00482 mol
L-1 and [HClO(g)] = 0.000 mol L-1.
[H2O(g)] = [ClO2(g)] = [HClO(g)] =
3.A flask that initially contained pure NO2 was
heated to 1000 K, a temperature at which the value of Kp
for the decomposition of NO2 is 128.8.
2NO2(g) <-----> 2NO(g) + O2(g)
Given that the partial pressure of O2 at equilibrium
equals 0.168 atm calculate the partial pressures of NO2
and NO at equilibrium.
PNO = PNO2 =
4.The equilibrium constant Kp for the
reaction,
2 SO3(g) <-------> 2 SO2(g) + O2(g)
is 8.440 at 789 °C. If a vessel at this temperature initially
contains pure SO3 and if the partial pressure of
SO3 at equilibrium is 0.050 atm, what is the partial
pressure of O2 in the flask at equilibrium?
What was the initial pressure of SO3 in the flask?
In: Chemistry
Calculate the percent dissociation of HF (Ka= 3.5x10^-4) in
(a) 0.050 M HF
(b) 0.50 M HF
In: Chemistry