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Viefleur [7K]
3 years ago
6

What is an example of a qualitative observation?

Chemistry
1 answer:
Lunna [17]3 years ago
7 0

Answer:

20 cats.

Explanation:

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Makes up the core of the other planets<br> stars with an M and ends with E
Sonbull [250]

Answer:

its iron not m or e

Explanation:

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Some atoms are chemically stable and will not bond with atoms of other
tigry1 [53]

Answer:

The stability of atoms depends on whether or not their outer-most shell is filled with electrons. If the outer shell is filled, the atom is stable. Atoms with unfilled outer shells are unstable, and will usually form chemical bonds with other atoms to achieve stability.

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The ksp of pbi2 is 1.4 x 10-8. what is the molar solubility of lead(ii iodide in a solution of 0.400 m sodium iodide?
tino4ka555 [31]
The solubility product of a substance us calculated by the product of the concentration of the dissociated ions in the solution raise to the stoichiometric coefficient of the ions. Therefore, we need the dissociation reaction. For this, it will have the reaction:

PbI2 = Pb^2+ + 2I-

We solve as follows:

Ksp = [Pb2+][I-]^2 = <span>1.4 x 10-8
</span><span>1.4 x 10-8 = x(2x)^2
</span><span>1.4 x 10-8 = 4x^3
x = 1.5x10^-3 M

The molar solubility would be </span>1.5x10^-3 M.
8 0
2 years ago
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; <em> 2 mL of the 25 μM stock solution will be taken and diluted with water up to 10 mL mark.</em>

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

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

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

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

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

<em />

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

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

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

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

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

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

6 0
3 years ago
2. Extract the relevant information from the question: NaOH V = 30 mL , M = 0.10 M HCl V = 25.0 mL, M = ?
Andrei [34K]

Answer:

0.12M

Explanation:

A balanced equation for the reaction will go a great deal in obtaining our desired result. So, let us write a balanced equation for the reaction

HCl + NaOH —> NaCl + H2O

From the above equation,

nA (mole of the acid) = 1

nB (mole of the base) = 1

Data obtained from the question include:

Vb (volume of the base) = 30mL

Mb (Molarity of the base) = 0.1M

Va (volume of the acid) = 25mL

Ma (Molarity of the acid) =?

The molarity of the acid can be obtained as follow:

MaVa/MbVb = nA/nB

Ma x 25/ 0.1 x 30 = 1

Cross multiply to express in linear form

Ma x 25 = 0.1 x 30

Divide both side by 25

Ma = (0.1 x 30) / 25

Ma = 0.12M

The molarity of the acid is 0.12M

5 0
3 years ago
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