There are 8.6 x 1025 atoms in a block of Tin (Sn). How many moles is the block of Tin?

2.A calibration curve requires the preparation of a set of known concentrations of CV, which are usually prepared by dieting a s

Aleks04 [339]

Answer:

In order to prepare 10 mL, 5 μM; 2 mL of the 25 μM stock solution will be taken and diluted with water up to 10 mL mark.

In order to prepare 10 mL, 10 μM; 4 mL of the 25 μM stock solution will be taken and diluted up to 10 mL mark.

In order to prepare 10 mL, 15 μM; 6 mL of the 25 μM stock solution will be taken and diluted up to 10 mL mark.

In order to prepare 10 mL, 20 μM; 8 mL of the 25 μM stock solution will be taken and diluted up to 10 mL mark.

Explanation:

Using the dilution equation:

no of moles before dilution = no of moles after dilution.

Molarity x volume (initial)= Molarity x volume (final).

In order to prepare 10 mL, 5 μM from 25 μM solution,

Final molarity = 5 μM, final volume = 10 mL, initial molarity = 25 μM, initial volume = ?

25 x initial volume = 5 x 10

Initial volume = 50/25

= 2 mL

2 mL of the 25 μM stock solution will be taken and diluted up to 10 mL mark.

In order to prepare 10 mL, 10 μM from 25 μM stock,

25 x initial volume = 10 x 10

Initial volume = 100/25 = 4 mL

4 mL of the 25 μM stock solution will be taken and diluted up to 10 mL mark.

In order to prepare 10 mL, 15 μM from 25 μM stock,

25 x initial volume = 15 x 10

initial volume = 150/25 = 6 mL

6 mL of the 25 μM stock solution will be taken and diluted up to 10 mL mark.

In order to prepare 10 mL, 20 μM from 25 μM stock,

25 x initial volume = 20 x 10

initial volume = 200/25 = 8 mL

8 mL of the 25 μM stock solution will be taken and diluted up to 10 mL mark.

6 0

3 years ago

During the daytime, wind blows off of the __________________ because that material takes ___________ time to get warm, creating

Butoxors [25]

Answer: sea, more

I hope this helps

5 0

2 years ago

What distinguishes a substance from a mixture?

wariber [46]

A mixture consists of numerous substances, whereas a substance does not consist of mixtures, but rather of compounds. Mixtures can be separated physically, while substances cannot.

4 0

3 years ago

Which pair of compounds represents one Arrhenius acid and one Arrhenius base?

erica [24]

Answer: C. HNO3 and NaOH

Explanation:

Arrhenius acid produces hydogen ion (H+) when dissolved in water. An example of Arrhenius acid is HNO3.

Arrhenius base produces hydroxyl ion (OH-) when dissolved water. An example of Arrhenius base is NaOH.

4 0

3 years ago

Use the reaction and bond information to answer the question. H2 CO2 → CH2O2 Reactant bond energies: H–H is 432 kJ/mol, C=O is 7

Anna11 [10]

The energy absorbed by the system before the reaction start has been 752 kJ/mol.

The bond energy has been defined as the energy possessed by the bond that has been converted into the heat energy and utilized in the reaction.

The energy has been conserved in a chemical reaction. Thus, the energy absorbed by the reactant in the reaction has been the difference in the energy of the reactant and product.

<h3>Computation for the energy absorbed</h3><h3 />

The given reaction has been:

$\rm H_2\;+\;CO_2\;\rightarrow\;CH_2O_2$

The bond energy of the reactant has been:

H-H bond energy = 432 kJ/mol

2 C=O bond energy= 799 kJ/mol

The total energy of the reactant has been 432 kJ/mol + 799 kJ/mol

The total energy of the reactant has been 1231 kJ/mol

The bond energy of the product has been:

C-O bonds = 358 kJ/mol

C=O bonds = 745 kJ/mol

1 C-H bond = 413 kJ/mol

1 O-H bond = 467 kJ/mol

The total energy of the product has been 358 + 745 + 413 + 467 kJ/mol

The total energy of the product has been 1,983 kJ/mol

According to the law of conservation of energy:

$\text{Product energy=Reactant energy + energy absorbed}$

Substituting the values for energy absorbed:

$\text{1,983 kJ/mol=1231\;kJ/mol+ energy absorbed}\\\rm Energy\;absorbed=1983-1231\;kJ/mol\\Energy\;absorbed=752\;kJ/mol$

The energy absorbed by the system before the reaction start has been 752 kJ/mol.

Learn more about bond energy, here:

brainly.com/question/866298

7 0

2 years ago