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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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2.4 g of a solid is added to 91 g of water. What is the mass % concentration of the solution?
vladimir2022 [97]

Answer:

2.64%

Explanation:

mass percent = (grams of solute / grams of solution) x 100

mass percent = (2.4 / 91) × 100

mass percent = 2.64% to 3sf

8 0
1 year ago
Which of the following is an example of a physical change? A) grinding coffee beans B) baking a cake C) converting water to hydr
lara [203]

Answer: A) grinding coffee beans

Explanation:

A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these reactions.

A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these reactions.

1. Grinding coffee : Only change in size takes place, thus a physical change

2. Baking a cake: the chemical reaction occurs by combination of flour with oxygen , thus a chemical change.

3.:converting water to hydrogen and oxygen: The decomposition iof water takes place, thus is a chemical change

4.Burning of coal: the chemical reaction occurs by combination of carbon with oxygen , thus a chemical change.

5 0
2 years ago
In part 1 of lab 2 you will make and standardize a solution of naoh(aq). suppose in the lab you measure the solid naoh and disso
Nostrana [21]
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3 0
3 years ago
Read 2 more answers
Identify each of the following mixtures as either homogeneous or heterogeneous and as a solution, a suspension, or a colloid.
MrRissso [65]
<h2>Answers to the rest of the assignment:</h2>

**Check for proof photos at the bottom.**

__________________________________________________________

Identify each of the following mixtures as either homogeneous or heterogeneous and as a solution, a suspension, or a colloid.  

Cranberry juice at the store

A. homogeneous

C. solution

Smoke  

B. heterogeneous  

D. colloid

__________________________________________________________

Identify each of the following mixtures as either homogeneous or heterogeneous and as a solution, a suspension, or a colloid.  

Blood

B. heterogeneous  

E. suspension

Salad dressing

B. heterogeneous  

E. suspension

__________________________________________________________

Shown here is a person shaving.  Under magnification, the shaving foam might look like the image above the shaver. What type of mixture does the foam demonstrate? Give your reasoning.

Foam is a colloid. Colloids includes gas dispersed in a liquid and it also includes gas dispersed in a solid

On the next slide, you can select any answers you want, or you can select nothing. There's no wrong answer.  

__________________________________________________________

A student squeezes several oranges to make a glass of orange juice. The juice contains pieces of orange pulp mixed with the juice. Explain why this drink can be considered a combination of a suspension and a solution.

The juice contains sugars, plant pigments, and other chemicals dissolved in water. This is a solution. The pieces of orange pulp will rise to the top or settle to the bottom of the juice if it is allowed to sit. The pieces of pulp mixed with the juice form a suspension

On the right side, you can also select any answers or none at all. There is no wrong answer.

__________________________________________________________

<h2>Explanation:</h2>

There are two main types of mixtures, homogeneous mixtures and heterogeneous mixtures. The components of a homogeneous mixture are evenly distributed throughout the mixture. The properties of a mixture are the same everywhere. The components of a heterogeneous mixture are not evenly distributed. Different regions of this mixture have different   properties.

Particles in a homogeneous mixture do not settle down or separate when left alone. Particles in a heterogeneous mixture eventually separate or settle when left alone.

  • Colloids are a type of heterogeneous mixture that do not naturally settle out quickly, and can be separated with different methods.
  • A suspension is another type of heterogeneous mixtures in which the components of the mixture will quickly settle out or can be filtered or separated.

Here are photos of Edge just incase.

6 0
3 years ago
When a hydrogen atom makes the transition from the second excited state to the ground state (at -13.6 eV) the energy of the phot
viktelen [127]

Answer : The energy of the photon emitted is, -12.1 eV

Explanation :

First we have to calculate the 'n^{th}' orbit of hydrogen atom.

Formula used :

E_n=-13.6\times \frac{Z^2}{n^2}ev

where,

E_n = energy of n^{th} orbit

n = number of orbit

Z = atomic number  of hydrogen atom = 1

Energy of n = 1 in an hydrogen atom:

E_1=-13.6\times \frac{1^2}{1^2}eV=-13.6eV

Energy of n = 2 in an hydrogen atom:

E_3=-13.6\times \frac{1^2}{3^2}eV=-1.51eV

Energy change transition from n = 1 to n = 3 occurs.

Let energy change be E.

E=E_-E_3=(-13.6eV)-(-1.51eV)=-12.1eV

The negative sign indicates that energy of the photon emitted.

Thus, the energy of the photon emitted is, -12.1 eV

3 0
3 years ago
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