1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Ksenya-84 [330]
3 years ago
12

The forensic technician at a crime scene has just prepared a luminol stock solution by adding 18.0 g of luminol to H2O creating

a solution with a total volume of 75.0 mL. What is the molarity of the stock solution of luminol?Before investigating the scene, the technician must dilute the luminol solution to a concentration of 5.00×10^-2 M. The diluted solution is then placed in a spray bottle for application on the desired surfaces.How many moles of luminol are present in 2.00 L of the diluted spray?What volume of the stock solution (Part A) would contain the number of moles present in the diluted solution (Part B)?
Chemistry
1 answer:
Bond [772]3 years ago
6 0

Answer:

Part A. 1.355 mol/L

Part B. 0.100 mol

Part C. 74.0 mL

Explanation:

Part A.

The molar mass of luminol is 177.16 g/mol, so the number of moles at 18.0 g is:

n = mass/molar mass

n = 18.0/177.16

n = 0.1016 mol

The molarity is the number of moles divided by the volume (0.075 L)

C = 0.1016/0.075

C = 1.355 mol/L

Part B.

The number of moles is the molarity multiplied by the volume, so:

n = 5.00x10⁻² mol/L * 2.00 L

n = 0.100 mol

Part C.

To prepare a solution by dilution, we can use the equation

C1V1 = C2V2

Where C1 is the concentration of the initial (stock) solution, V1 is its volume necessary, C2 is the concentration of the diluted solution, and V2 is its volume.

Thus, C1 = 1.355 M, C2 = 0.05 M, V2 = 2.00 L

1.355V1 = 0.05*2

V1 = 0.074 L

V1 = 74.0 mL

You might be interested in
the empirical formula for a compound used as a green paint pigment is C2H3As3Cu2O8. The molar mass of its molecular formula was
melisa1 [442]

Answer:

Molecular formula = C₄H₆As₆Cu₄O₁₆

Explanation:

Given data:

Empirical formula = C₂H₃As₃Cu₂O₈

Molar mass of compound = 1013 g/mol

Molecular formula = ?

Solution:

Molecular formula = n (empirical formula)

n = molar mass of compound / empirical formula mass

Empirical formula mass  of C₂H₃As₃Cu₂O₈ is 506.897 g/mol

by putting values.

n = 1013 / 506.897

n = 2

Molecular formula = n (empirical formula)

Molecular formula = 2 (C₂H₃As₃Cu₂O₈)

Molecular formula = C₄H₆As₆Cu₄O₁₆

3 0
3 years ago
What is the total ionic equation for cuso4+2naoh>>cu(oh)2+na2so4
iVinArrow [24]

Answer:

CuSO4 + 2 NaOH = Cu(OH)2 + Na2SO4

3 0
3 years ago
The maximum allowable concentration of pb2+ ions in drinking water is 0.05 ppm (i.e., 0.05 g of pb2+ in 1 million grams of water
trasher [3.6K]
PbSO₄ partially dissociates in water. the balanced equation is;
                    
                       PbSO₄(s) ⇄  Pb²⁺(aq) + SO₄²⁻(aq)
Initial                                     -                -
Change             -X               +X           +X
Equilibrium                           X              X

Ksp           =    [Pb²⁺(aq)] [SO₄²⁻(aq)]
1.6 x 10⁻⁸  =    X * X
1.6 x 10⁻⁸  =    X²
          X    =   1.3 x 10⁻⁴ M
      
Hence the Pb²⁺ concentration in underground water is 1.3 x 10⁻⁴ M. 
[Pb²⁺]  = 1.3 x 10⁻⁴ M.
           = 1.3 x 10⁻⁴ mol / L x 207 g / mol 
           = 26.91 ppm

8 0
3 years ago
Calculate the mass of H2OH2O produced by metabolism of 2.4 kgkg of fat, assuming the fat consists entirely of tristearin (C57H11
otez555 [7]

Answer:

2,669.58 grams of water will be produced by metabolism of 2.4 kilogram of fat.

Explanation:

2C_{57}H_{110}O_6+163O_2\rightarrow 114CO_2+110H_2O

Mass of fat = 2.4 kg = 2.4 × 1000 g = 2400 g

1 kg = 1000 g

Molar mass of fat = M

M = 57 × 12 g/mol + 110 × 1 g/mol+ 6 × 16 g/mol = 890 g/mol[/tex]

Moles of fat = \frac{2400 g}{890 g/mol}=2.6966 mol

According to reaction , 2 moles of fat gives 110 moles of water. Then 2.6966 moles of fat will give  ;

\frac{110}{2}\times 2.6966 mol=148.31 mol of water

Mass of 148.31 moles of water ;

148.31 mol × 18 g/mol = 2,669.58 g

2,669.58 grams of water will be produced by metabolism of 2.4 kilogram of fat.

8 0
3 years ago
Non motile in an sentences
allsm [11]

Answer:

Motile bacteria have flagella, while nonmotile bacteria do not.

Explanation:

4 0
3 years ago
Other questions:
  • As a person ages his or her levels of cardiorespiratory fitness tend to
    9·2 answers
  • What are resources?​
    14·1 answer
  • Force F with arrow = (9.0 N)i hat − (9.0 N)k acts on a pebble with position vector r with arrow = (0.90 m)j − (1.2 m)k relative
    5·1 answer
  • If the last carbon atom of an unsaturated fatty acid is bonded to two hydrogen atoms and one carbon atom, what type of bond must
    12·2 answers
  • A sample of iron (III) chloride has a mass of 26.29g. How many moles would this be?
    8·1 answer
  • Define acidic salt with example​
    14·2 answers
  • The area in which an object experiences a noncontact force is called a field. Examples of fields include electrical fields, magn
    12·1 answer
  • What are the characteristics of binding energy
    5·2 answers
  • When the sun runs out of hydrogen in its core, it will become larger and more luminous because:.
    10·2 answers
  • Why does radiation decrease over time?
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!