Question

Tooth enamel is Ca_{5}(PO_{4})_{3}(OH).
Calculate the percent composition of the elements present. please
show work

Answer #1

Tooth enamel consists mainly of the mineral calcium
hydroxyapatite,
Ca10(PO4)6(OH)2. Trace
elements in teeth of archeological specimens provide
anthropologists with clues about diet and diseases of ancient
people. Students at Hamline University used atomic absorption
spectroscopy to measure strontium in enamel from extracted wisdom
teeth. Solution were prepared with a constant total volume of 10.0
mL containing 0.750 mg of dissolved tooth enamel plus variable
concentrations of added Sr standard:
Added Sr, ppb
Absorbance- reagent blank
0
0.100
2.00
0.155...

please show work -
For the reaction: H2SO4(aq) +
Al(OH)3 ↔ H2O + Al(OH)(SO4) ;
calculate the equivalent weight of Al(OH)3.
A.26
B.39
C.78

The formal composition of an aqueous solution is 0.12 M K2HPO4 +
0.08 KH2PO4. The pKa's for triprotic phosphoric acid are 2.12,
7.21, and 12.32. Show the three equilibriums in solution and
calculate the pH of the solution. Find concentrations of K+, H3PO4,
H2PO4^-, HPO4^2-, PO4^3-, H+, and OH^- in the mixture.

PLEASE SHOW WORK
4. Calculate the [H+], pH and percent dissociation of a solution
that is 0.50 M in HOCl and 0.60 M in NaOCl.
5. Calculate the [H+], pH and percent dissociation of a solution
that is 1.0 M in aniline (C6H5NH2) and 1.2 M in C6H5NH3Cl.
6. A solution contains 0.60 mol of NH4Cl and 0.30 mol of NH3 in
1.5 L. What is the pH if 0.070 mol of HCl is added to this
buffer?

Calculate the pH and the concentrations of all species present
(H3O+, OH?, HIO3, and IO?3) in 0.0530M HIO3. Ka for HIO3is
1.7

LIMITING REAGENT PROBLEM: Show your work! PLEASE MAKE SURE IT IS
CLEAR HOW THE MOLES OF Ba3(PO4)2 and NaNO3 are found and be
descriptive with the entire process.
Consider the reaction and complete the following table:
2 Na3PO4 + 3 Ba(NO3)2 ----> Ba3(PO4)2 + 6
NaNO3
Initial Mass
100.0grams
100.0grams
-----------------
-----------
Change in Mass…. Amount used
or formed
Final mass
Molar Masses: Na3PO4 = 164 grams/mole Ba(NO3)2 = 261 grams/mole
Ba3(PO4)2 = 602 grams/mole NaNO3 = 85 grams/mole
b)...

Please show all your work!
Exp
Composition
Total Vol
pH
1
A few mL of 0.10M NH3 (unchanged)
n/a
11.13
2
2.5mL 0.1M NH3 & 7.5mL H2O
10 ml
10.82
3
2.5mL 0.1M NH4Cl & 7.5mL H2O
10 ml
6.01
4
2.5mL 0.1M NH3 & 2.5mL 0.1M NH4Cl
& 5mL H2O
10 ml
9.26
5
Take 1mL Solution #4 and add 9mL of water
10 ml
9.26
Calculate the concentrations for solution 4 and solution 5
Sol
Conc. NH3 (M)...

The answor of a is 95.5 and the answor of b is 2.75 please show
work
11.0 (20 pts) A unidirectional fiber-epoxy resin composite
contains a 89 % fiber volume with epoxy resin for the remaining
volumne fraction. Determine the (a) % composition of fiber by
weight and (b) the average density of the composite. The fiber and
resin densities are 2.95 and 1.21 g/cm^3, respectively. Fiber comp
(wt%) = _____95.5___ ? = ____2.75____
The answor of a is 95.5...

Calculate Independent t-test and effect size (please show
work)
Treatment
Control
3
4
5
6
4
3
4
5

The dissociation constant for salicylic acid,
C6H4 (OH)COOH, is 1.0 x 10-3.
Calculate the percent dissociation of a 0.10 M salicylic acid
solution. (Ignore water dissociation).

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