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VashaNatasha [74]
3 years ago
11

What is the definition of periodic trend

Chemistry
1 answer:
Black_prince [1.1K]3 years ago
4 0

Answer:

That periodic trends are specific patterns that are present in the periodic table that illustrate different aspects of a certain element, including its size and its electronic properties.

Explanation:

You might be interested in
How many moles of neon (Ne) gas have a volume of 4.5L and a pressure of 2.1 atm at 302 K
Montano1993 [528]

Answer:

0.3811 mol.

Explanation:

  • To calculate the no. of moles of a gas, we can use the general law of ideal gas: <em>PV = nRT</em>.

where, P is the pressure of the gas in atm.

V is the volume of the gas in L.

n is the no. of moles of the gas in mol.

R is the general gas constant,

T is the temperature of the gas in K.

∵ P = 2.1 atm, V = 4.5 L, T = 302 K, R = 0.0821 L.atm/mol.K.

<em>∴ n = PV/RT </em>= (2.1 atm)(4.5 L)/(0.0821 L.atm/mol.K)(302.0 K) = <em>0.3811 mol.</em>

7 0
3 years ago
What kind of substance should be handled in a fumed chamber?
svet-max [94.6K]

Answer:

D. flammable​

Explanation:

Hope this helps :)

4 0
3 years ago
Read 2 more answers
Which of these is the most accurate description of the job of an art conservationist?
stiv31 [10]

Answer:

Cultural conservation is concerned with how cultural material is preserved as it moves from the past, through the present and into the future. This material may be books in libraries, documents in archives, objects or artwork in museums, or items owned by a community, a family or an individual.

It is the conservator’s job to help ensure the material’s protection and safe passage into the future for as long as is possible.

Art conservation is a complex and highly interdisciplinary task, requiring a knowledge base that may include methods of manufacture, the mechanisms of damage and the cultural significance of an object. Art conservators use history to understand why and when an artwork was made and science to understand how it was made and what has happened to it over time.

When the history of a painting is unclear, conservators will turn to art history to contextualise the work and to science to investigate the evidence of the date and method of manufacture.

Thorough examination and documentation is always the first step in conservation. This involves assessing the original structure and materials of the object, the extent of deterioration, damage and loss, and to ascertain previous restorations or other interventions.

Restoration and preventative conservation

Walters Art Museum

The terms “conservation” and “restoration” are often used interchangeably, but they represent very different activities.

Restoration seeks to modify the appearance of an object to reduce the visual impact of deterioration or damage and to restore visual continuity. Although conservation may involve restoration, more usually it’s engaged with preventing damage and deterioration.

Preventive conservation brings knowledge of the mechanisms of deterioration to provide the best options for the long-term care of cultural material. Take the example of a newspaper page turning yellow and brittle in the hot summer sun – knowing how the cellulose in the paper ages, that this process involves the creation of acid and that this acid contributes to the discolouration and deterioration of paper, means that appropriate steps can be taken to mitigate this process.

Preventative conservation is a predictive and holistic activity, often involving whole collections.

The operational aspects of air conditioning in museums are often the concern of conservators. Chemical and physical reactions involved in deterioration increase with higher temperatures and with cyclic changes in humidity. As a result, materials may crack or become brittle.

On one hand it makes sense to have continuous and stable air-conditioning; on the other hand, air-conditioning is energy-intensive and expensive to run. Understanding the issues, weighing the risks and advising on the best options for the collection is the job of the conservator.

Craftsmanship and ethics

Conservation also requires exceptional craftsmanship and art-making skills such as those employed in the original creation of the artwork; being able to replicate the paint layers, carve a section of an object to replace a lost part, or cast a sheet of handmade paper to use as a fill for a large hole are some examples of these kinds of skills.

There are also conservation-specific skills. The torn edges of a painting’s canvas support may need to be rewoven thread by thread. A hole may require a patch which will then require a complex fill of the ground layer (the layer of gesso applied to the canvas to provide a smooth painting surface), paint and varnish that replicates the surrounding painting.

Elizabeth Buie

In some cases the painting’s conservator will simple “tone” areas, adjusting the degree of lightness or darkness, so that the viewer can still read the extent of damage in the image. In other cases the conservator will make the image as complete as possible by “inpainting”, reconstructing lost or deteriorated parts, so that the loss is virtually invisible.

Art conservation became a profession in Australia in 1973 and concerned at how best to support and develop programs for cultural materials conservation, the Australian Institute for the Conservation of Cultural Material (AICCM).

Under the AICCM’s Code of Ethics and Code of Practice, any intervention by a conservator on an object has to be reversible – in practice, that means using materials and techniques that can be removed easily in the future.

That’s one reason why an oil painting is never inpainted with oil paint. Oil paint cross-links with age until it forms a hard, plastic surface. In a few short decades a restoration done in oil paint will only be able to be removed with solvents that are strong enough to also remove the original paint.

This concept of reversibility is aligned to the concept of minimal intervention; and both require good documentation, usually a condition and treatment report accompanied by good images.

Explanation:

4 0
3 years ago
Which of the following statements best describes the relationships between carrying captivity in population size
Ierofanga [76]

The correct answer is letter a, whereas, carrying capacity in captivity increases population size. It is because the carrying captivity is the one responsible for having a maximum population size in which will help in sustaining the necessities that the species need in the environment in which makes it responsible for the population size to increase depending on its capacity. The correct answer is letter a.

4 0
4 years ago
Be sure to answer all parts. The percent by mass of bicarbonate (HCO3−) in a certain Alka-Seltzer product is 32.5 percent. Calcu
pochemuha

Answer : The volume of CO_2 will be, 514.11 ml

Explanation :

The balanced chemical reaction will be,

HCO_3^-+HCl\rightarrow Cl^-+H_2O+CO_2

First we have to calculate the  mass of HCO_3^- in tablet.

\text{Mass of }HCO_3^-\text{ in tablet}=32.5\% \times 3.79g=\frac{32.5}{100}\times 3.79g=1.23175g

Now we have to calculate the moles of HCO_3^-.

Molar mass of HCO_3^- = 1 + 12 + 3(16) = 61 g/mole

\text{Moles of }HCO_3^-=\frac{\text{Mass of }HCO_3^-}{\text{Molar mass of }HCO_3^-}=\frac{1.23175g}{61g/mole}=0.0202moles

Now we have to calculate the moles of CO_2.

From the balanced chemical reaction, we conclude that

As, 1 mole of HCO_3^- react to give 1 mole of CO_2

So, 0.0202 mole of HCO_3^- react to give 0.0202 mole of CO_2

The moles of CO_2 = 0.0202 mole

Now we have to calculate the volume of CO_2 by using ideal gas equation.

PV=nRT

where,

P = pressure of gas = 1.00 atm

V = volume of gas = ?

T = temperature of gas = 37^oC=273+37=310K

n = number of moles of gas = 0.0202 mole

R = gas constant = 0.0821 L.atm/mole.K

Now put all the given values in the ideal gas equation, we get :

(1.00atm)\times V=0.0202 mole\times (0.0821L.atm/mole.K)\times (310K)

V=0.51411L=514.11ml

Therefore, the volume of CO_2 will be, 514.11 ml

6 0
3 years ago
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