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Doss [256]
3 years ago
15

Hardness of metals can be decreased by: (a) adding interstitial alloying elements (b) making glassy metals through extremely hig

h cooling rates (c) annealing using slow cooling from high temperatures (d) cold-working or deforming at low temperatures
Chemistry
1 answer:
n200080 [17]3 years ago
4 0

Answer:

Option c is correct

Explanation:

The interstitial alloy elements occupy the free spaces in the metal structure and improve the symmetry of the crystalline network, for this reason this type of elements increases the hardness of the metal.

Vitreous metals are called that because they are formed by high cooling rates and form amorphous structures such as glass, such structures contain packaging of atoms of different sizes, which decreases the free spaces in the metal structure and this increases their hardness.

In option d, the work at low temperatures causes the vibrations of the atoms to decrease and compact, this makes many metals brittle but in general increases their hardness.

Option c is correct because in annealing the metal is heated to the austenization temperature, that is, the temperature at which a structural change occurs, which destroys its crystalline network and then slowly cools to maintain this structure change and by causing this disorder, the spaces between the atoms increase and the hardness of the metal decreases.

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In Lab 10 you make a stock solution of salicylic acid, and then four dilutions. The stock solution is made by diluting 5.00 ml o
Zigmanuir [339]

Answer:

Stock  solution =  1.25 *10^-3 M

Dilution 1 = 5*10^-4 M

Dilution 2= 3.75 * 10^-4 M

Dilution 3 = 2.5 *10^-4 M

Dilution 4 = 1.25 *10^-4 M

Explanation:

<u>Step 1:</u> Data given

The stock solution is made by diluting 5.00 ml of 1.250 x 10-2 M salicylic acid in 50.00 mL of solution.

<u>Step 2</u>: Calculate the concentration of the stock solution:

M1*V1 = M2*V2

⇒ with M1 = the initial concentration = 1.250 *10^-2 M

⇒ with V1 = 5 mL = 5*10^-3 L

⇒ with M2 = TO BE DETERMINED

⇒ with V2 = 50 mL = 50 *10^-3 L

M2 = (M1*V1)/V2

M2 = (1.250 *10^-2 * 5*10^-3 L) / 50 *10^-3

M2 = 0.00125 M = 1.25 *10^-3 M

<u>Step 3:</u> Calculate dilution 1

M2 = (M1*V1)/V2

M2 = (1.25*10^-3 * 10 *10^-3)/(25*10^-3L)

M2 = 0.0005 M = 5*10^-4 M

<u>Step 4</u>: Calculate dilution 2

M2 = (M1*V1)/V2

M2 = (1.25*10^-3 * 10 * 7.5*10^-3)/(25*10^-3)

M2 = 0.000375 M = 3.75 * 10^-4 M

<u>Step 5:</u> Calculate dilution 3

M2 = (M1*V1)/V2

M2 = (1.25*10^-3 * 5*10^-3) /(25*10^-3)

M2 = 0.00025 M = 2.5 *10^-4 M

<u>Step 6</u>: Calculate dilution 4

M2 = (M1*V1)/V2

M2 = (1.25*10^-3 * 2.5*10^-3)/(25*10^-3)

M2 = 0.000125 M = 1.25 *10^-4 M

5 0
4 years ago
What do atoms form when they bond chemically?
V125BC [204]
They form molecules which can be in solution form if diluted in water, but some do form solutions on exposure to the atmosphere i.e they are deliquescent like pellets of sodium hydroxide
7 0
3 years ago
Three 6−l flasks, fixed with pressure gauges and small valves, each contain 6 g of gas at 276 k. flask a contains ch4, flask b c
Margaret [11]

First, please check the missing part in your question in the attachment.

a) So first, the Rank of pressure:

according to this formula PV = nRT and when n = m/Mw

PV = m/Mw * R*T

when we have the same mass m and the same V volume so P will proportional with the mole weight M as when the M is smaller the pressure will be greater 

when Mw of H2(A) = 2 g / Mw of He (B) = 4 g and Mw of CH4(C) = 16 g

∴ Pressure :

 (A) > (B) > (c)

B) The rank of average molecular kinetic energy:

when K = 3/2 KB T

when K is the average kinetic energy per molecule of gas 

and KB is Boltzmann's constant

and T is the temperature (K)

So from this equation, we can know that K only depends on T value, and when we have the T constant here for A, B, and C So the rank of K will be like the following:

∴ A = B = C

C) the rank of diffusion rate after the valve is opened:

according to this formula:

R2/R1 = √M1/M2

from this equation, we can see that diffusion is proportional to the reciprocal of the molecular mass M so,

when Mw H2 (A) = 2 g & Mw He(B) = 4 g & CH4 (C) = 16 g

∴ the rank of diffusion:

A > B > C

D) The rank of the Total kinetic energy of the molecules:

when we have the Mw different so it will make the no.of molecules differs as when the Mw is low the no.of molecules will be hight, and when the average molecular kinetic energy equals. so the total kinetic energy will depend on no. of molecules 

∵ Mw A < Mw B < Mw C 

∴no .of molecules of A > B >C

∴ the rank of total kinetic energy is:

A > B > C

e) the rank of density:

when ρ = m/ v 

and m is the mass & v is the volume and we have both is the same for A, B, and C

so the density also will be the same, ∴ the rank of the density is:

A = B = C

F) the rank of the collision frequency:

as the no.of molecules increase the collision frequency increase and depend also on the velocity and it's here the same.

∴ Collision frequency will only depend on the no.of molecules

we have no.of molecules of A > B > C as Mw A < B < C 

∴the rank of the collision frequency is:

A > B > C 

6 0
3 years ago
Which material is very strong and tough but shows very little elongation as it absorbs energy?
natita [175]
Kevlar would be the answer!! enjoy the rest of your day broskies!!!
7 0
3 years ago
An Arrhenius acid increases the concentration of hydrogen ions when dissolved in solution. True False
shusha [124]

Answer:

True

Explanation:

The arrhenius theory describes an acid as a substance that produces excess hydrogen ions when it interacts with water. Therefore, they increase the concentration of hydrogen ions in solutions.

An arrhenius base interacts with water to yield excess hydroxide ions in aqeous solutions.

4 0
3 years ago
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