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2 years ago

Instrumental methods need only a microscopic sample to return an accurate result. Why is this so?

1 answer:

3 0

Instrumental methods of analysis rely on machines.The visualization of single molecules, single biological cells, biological tissues and nanomaterials is very important and attractive approach in analytical science.
There are several different types of instrumental analysis. Some are suitable for detecting and identifying elements, while others are better suited to compounds. In general, instrumental methods of analysis are:
-Fast
-Accurate (they reliably identify elements and compounds)
-Sensitive (they can detect very small amounts of a substance in a small amount of sample)

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Which balanced redox reaction is occurring in the voltaic cell represented by the notation of A l ( s ) | A l 3 ( a q ) | | P b

frez [133]

The question is missing. Here is the complete question.

Which balanced redox reaction is ocurring in the voltaic cell represented by the notation of $Al_{(s)}|Al^{3+}_{(aq)}||Pb^{2+}_{(aq)}|Pb_{(s)}$ ?

(a) $Al_{(s)}+Pb^{2+}_{(aq)} ->Al^{3+}_{(aq)}+Pb_{(s)}$

(b) $2Al^{3+}_{(aq)}+3Pb_{(s)} -> 2Al_{(s)}+3Pb^{2+}_{(aq)}$

(d) $2Al_{(s)}+3Pb^{2+}_{(aq)} -> 2Al^{3+}_{(aq)}+3Pb_{(s)}$

Answer: (d) $2Al_{(s)}+3Pb^{2+}_{(aq)} -> 2Al^{3+}_{(aq)}+3Pb_{(s)}$

Explanation: Redox Reaction is an oxidation-reduction reaction that happens in the reagents. In this type of reaction, reagent changes its oxidation state: when it loses an electron, oxidation state increases, so it is oxidized; when receives an electron, oxidation state decreases, then it is reduced.

Redox reactions can be represented in shorthand form called cell notation, formed by: left side of the salt bridge (||), which is always the anode, i.e., its half-equation is as an oxidation and right side, which is always the cathode, i.e., its half-equation is always a reduction.

For the cell notation: $Al_{(s)}|Al^{3+}_{(aq)}||Pb^{2+}_{(aq)}|Pb_{(s)}$

Aluminum's half-equation is oxidation:

$Al_{(s)} -> Al^{3+}_{(aq)}+3e^{-}$

For Lead, half-equation is reduction:

$Pb^{2+}_{(aq)}+2e^{-} -> Pb_{(s)}$

Multiply first half-equation for 2 and second half-equation by 3:

$2Al_{(s)} -> 2Al^{3+}_{(aq)}+6e^{-}$

$3Pb^{2+}_{(aq)}+6e^{-} -> 3Pb_{(s)}$

Adding them:

$2Al_{(s)}+3Pb^{2+}_{(aq)} -> 2Al^{3+}_{(aq)}+3Pb_{(s)}$

The balanced redox reaction with cell notation $Al_{(s)}|Al^{3+}_{(aq)}||Pb^{2+}_{(aq)}|Pb_{(s)}$ is

$2Al_{(s)}+3Pb^{2+}_{(aq)} -> 2Al^{3+}_{(aq)}+3Pb_{(s)}$

6 0

2 years ago

If charges flow very slowly through a metal, why does it not require several hours for a light to come on when you throw a switc

Harlamova29_29 [7]

The charges themselves may not move fast, but the force upon them does. The electric field set up by the battery or generator propagates through the wires at the speed of light.

Thank you for posting your question here at brainly. I hope the answer will help you. Feel free to ask more questions.

6 0

2 years ago

Identify the type of solid from the description. Select from the following choices: metallic solid, network solid, molecular sol

scZoUnD [109]

First of all, there are five types of solid materials:

Metallic solids which are solids composed of metal atoms that are held together by metallic bonds.

Network solid is a chemical compound in which the atoms are bonded by covalent bonds in a continuous network extending throughout the material.

Molecular solid is a solid consisting of discrete molecules.

Ionic solid is a chemical compound composed of ions held together by electrostatic forces termed ionic bonding.

Amorphous solid is non-crystalline solid that lacks the long-range order that is characteristic of a crystal.

Now, after the defined all the types of solid materials in the equation lets to solve it.

A. the answer is the network solids, because covalent bonds are relatively strong, covalent are typically characterized by hardness, strength, and high melting points.

B. the answer is the metallic solids, due to that heat conduction occurs when a substance is heated and the particles will gain more energy vibrating more. These molecules then bump into nearby particles and transfer some of their energy to them and in metals this process have a higher probability than in the case of other solids due to the nature of the chemical bonds. It also has a range of hardness due to the strength of metallic bonds which varies dramatically.

C. the answer is the ionic solid; due to positive and negative ions which are bonded to form a crystalline solid held together by charge attractions.

4 0

2 years ago

How many grams of nano3 would you add to 500g of h2o in order to prepare a solution that is 0.500 molal in nano3?

VARVARA [1.3K]

When the concentration is expressed in molality, it is expressed in moles of solute per kilogram of solvent. Since we are given the mass of the solvent, which is water, we can compute for the moles of solute NaNO3.

0.5 m = x mol NaNO3/0.5 kg water
x = 0.25 mol NaNO3

Since the molar mass of NaNO3 is 85 g/mol, the mass is

0.25 mol * 85 g/mol = 21.25 grams NaNO3 needed

4 0

2 years ago

. Divide 94.20 g by 3.167 22 mL.

jeka94

94.20 g/3.16722 mL = 29.74 g/mL

The ratio of mass to volume is equal to the substance's density. Thus, 29.74 g/mL is the density of whatever substance it may be. Density does not change for incompressible matter like solid and some liquids. Although, it may be temperature dependent.

7 0

1 year ago

Read 2 more answers