helium has a molecular weight of 4.003. what is the weight of 2 cubic meters of helium at 1 atmosphere and 20°c?

The average atomic mass of the element is 25.75 amu.

m(²⁵X) = 25.0 amu; the average atomic mass of isotope-25

m(²⁸X) = 28.0 amu; the average atomic mass of isotope-28

ω(²⁵X) = 75.0% ÷ 100%

ω(²⁵X) = 0.750; fractional abudance of isotope-25

ω(²⁸X) = 25.0% ÷ 100%

ω(²⁸X) = 0.250; fractional abudance of isotope-28

m(X) = m(²⁵X) × ω(²⁵X) + m(²⁸X) × ω(²⁸X).

m(X) = 25.0 amu × 0.750 + 28.0 amu × 0.250

m(X) = 25.75 amu; average atomic mass of an element

The unified atomic mass unit (amu) is a standard unit of atom.

Isotopes are chemical elements with same atomic number, but different atomic mass (different number of neutrons).

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Answer:

Explanation:

Copper mining is usually performed using open-pit mining, in which a series of stepped benches are dug deeper and deeper into the earth over time. To remove the ore, boring machinery is used to drill holes into the hard rock, and explosives are inserted into the drill holes to blast and break the rock.

A strong acid like hcl dissociates completely in an aqueous solution

A Brnsted-Lowry acid or Lewis acid is a molecule or ion that has the ability to donate a proton or establish a covalent bond with an electron pair. Proton donors, also known as Brnsted-Lowry acids, are the first class of acids.

LSD, sometimes known as acid, is the chemical name for lysergic acid diethylamide. Given that it's a potent psychedelic, you run the risk of seeing things and reality differently if you use it. Tripping is the term used to describe the LSD experience. Acidic substances fall below 7.0, while alkaline or basic substances rise above 7.0.

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Physical, chemical, pure substance, and mixture are all categories of properties of matter.

What is Matter?

Therefore, physical, chemical, pure substances, and mixtures are the main categories of matter.

Hence, all the given options are correct.

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DNA is made up of genes that carry hereditary information

The molecule inside cells that contains the genetic information responsible for the development and function of an organism and DNA molecules allow this information to be passed from one generation to the next generation and a molecule that contains the biological instructions that make each species unique

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Answer: here is the answer, I tried. lol, remember to re-write it!

The first stage is where it rains into grass, water, anything. Then it goes into the air and into more clouds, and produce more rainfall, which is evaporation. After that, it goes into precipitation, where it can cause hair, mist, rain, or snow. Then condensation, where water collects droplets when there is humid air, into the clouds. Then runoff, where the water is transported to a new location to produce rainfall.

If this symbol is seen on a chemicals bottle, it means that it is an oxidizing chemical.

In a chemical laboratory there is usually a special cabinet for the storage of chemicals. The chemicals that are stored are often chemicals that are used to carry out one kind of experiment or the other in the laboratory.

However, symbols are used to symbolize the peculiarity of each particular chemical. Now we can see the symbol as shown in the image attached. If this symbol is seen on a chemicals bottle, it means that it is an oxidizing chemical.

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The apparatus used are dewer vessel 1000ml capacity complete with cover, electric stirrer 300rpm, base with stand, and W = zinc, X = aluminium, Y = magnesium, Z = iron and metals reactivity is chart listing metals in order of decreasing reactivity

Here given data is Four different powdered metals W,X,Y, Z react with Dilute sulfuric acid

When W=zinc, X=aluminium, Y=magnesium, Z=iron this four metals are reactive with Dilute sulfuric acid then give ZnSO₄, Al₂(SO)₃,  MgSO₄, FeSO₄ and magnesium is very active metal and gold and platinum are not react with Dilute sulfuric acid and apparatus used are dewer vessel 1000ml capacity complete with cover, electric stirrer 300rpm, base with stand

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The first wave appear after 320 seconds and after the arrival of P wave

We can use the formula TD = d × t / 100 km

TD = d × t / 100 km

= ( 4000 km × 8 s ) / 100 km

= 32000 km /s / 100 km

= 320 seconds

The first s-wave will arrived in 320 seconds after the arrival of the first p-wave

The earliest waves to reach a seismograph are known as P waves, or primary waves. The fastest seismic waves, known as P waves, can pass through solid, liquid, or gas. On the medium they travel through, they leave a trail of compressions and rarefactions

The second waves to arrive during an earthquake are called S waves, or secondary waves. They can only pass through solids and are substantially slower than P waves

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Sugar has 12 elements of carbon, 22 elements of hydrogen, and 11 elements of oxygen.

Salt has 1 element of sodium, and 1 chlorine

Baking soda has 1 sodium, 1 hydrogen, 1 carbon and 3 oxygen

A chemical element is a substance that cannot be further broken down by any chemical reaction.

Each element has its own specified number of proton in their nuclei.

An element’s atoms must all have the same number of protons but they can have different numbers of neutrons and hence different masses.

Examples of elements include:

Some elements are more abundant that others in the universe. At 75 percent, hydrogen is the most abundant element in the universe, followed by helium at 23 percent, then oxygen at 1 percent.

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A rock will scratch with a fingernail but not a copper penny then according to Mohs hardness scale, the student will determine that the rock is more harder than fingernail and copper penny.

Mohs hardness scale can be defined as a qualitative ordinal scale ranges from one to ten characterizing the scratch resistance of various minerals through the ability of harder material to the softer material.

Hardness can be defined as the measure of the material resistance to localized permanent deformation. Permanent deformation is also known as plastic deformation.

Thus,  rock will scratch with a fingernail but not a copper penny then according to Mohs hardness scale, the student will determine that the rock is more harder than fingernail and copper penny.

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Answer:

I think in period 2

Explanation:

Mallory should look to find another element that has similar properties to those of Fluorine in Group 17 and is denoted as option D.

This is defined as the arrangement of elements based on their atomic number in a tabular form. It consists of 18 vertical columns which are referred to as groups and seven horizontal rows called period.

Group 17 contains halogens such as fluorine, iodine etc and they have similar properties which is therefore the reason why it should be looked at for another element in this type of scenario.

This is also the most appropriate choice is option D.

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Answer:

Explanation: A children's liquid medicine contains 100 mg of the active ingredient in 5 mL . If a child should receive 150 mg of the active ingredient, how many milliliters

A research chemist is trying to create a new plastic to be used as a food container that is more durable and lighter than glass, and so cheaper to transport which is an example of research chemistry that benefits the environment.

This is referred to as the physical surrounding or conditions in which an organism lives and contains living and non-living components which have various forms of influence on human life.

Plastic is a substance which is hard to decompose and takes many years and also has the tendency to release harmful chemicals into the environment. The creation of one which more durable and easier to transport means there will be less plastic wastes.

This will therefore reduce various forms of pollution and benefit the environment at large and is therefore the reason why it was chosen ad the correct choice.

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.53 micrometers

take away the zeros and decimal it

If a hydrolysis reaction forms a carboxylic acid from an ester and water, the other product will be an alcohol.

Hydrolysis breaks down compounds by adding a water molecule.

Hydrolysis is a reaction that breaks down the chemical bonds between molecules via the addition of a water molecule.

Hydrolysis of an ester gives an alcohol and a carboxylic acid:

R-COOR + H₂O ⇄ R-COOH + R-OH

R-COOR is general molecular formula of an ester.

H₂O is water.

R-COOH is general molecular formula of a carboxylic acid.

R-OH is general molecular formula of an alcohol.

An ester is a compound in which at least one hydroxyl group is replaced by an alkoxy group.

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Answer:

[tex]b[/tex]

[tex]temperature[/tex]

The element that requires the least amount of energy to remove the outer-most electron from a gaseous atom in the groud state is Sodium (Na). That is option 3.

A group state of an atom is defined as the level of energy attained by an atom in which all its electrons are in the lowest possible energy levels.

From the periodic table, the elements are arranged in groups and periods according to their atomic mass number.

From the atoms listed, sodium is element that requires the least amount of energy to remove the outer-most electron from a gaseous atom in the groud state.

This is so because of the following reasons:

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Complete question

Which Element Requires The Least Amount Of Energy To Remove The Most Loosely Held Electron From A Gaseous Atom In The Ground State?

(1) bromine

(2) calcium

(3) sodium

(4) Silver

The correct option is B.

Resting potential is the state of a neuron when it is not firing a neural impulse.

Resting potential is considered as the imbalance of electrical charge which existed between electrically excitable neurons or nerve cells in the interior and in their surroundings.

The resting membrane potential of a particular cell defines as the difference in electrical potential across the plasma membrane as when the cell exists in a non-excited state. The electrical potential difference that takes place across a cell membrane traditionally is expressed inside the cell by its value which is relative to the extracellular environment

When the condition of not sending a signal by a neuron takes place, it is considered to be at the "rest" stage. When a neuron exists at rest position, the inside region of a neuron is negative with respect to the outside.

The potential is recorded whenever a living cell is impaled with a microelectrode and is termed as the resting potential and it varies from one cell to another cell. Here it is valued to be -60 mV, but the value can range between -80 mV and -40 mV which depends on the particular type of nerve cell existed.

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Here independent variable is Time spent on studying.

In this case group of students can change their duration of time which they spent on studying. it could be 1 hour a night, 4 hour a night or anything therefore time spent on studying is independent variable.

Time they spent on studying will directly affect their final exam grade at the end of the 6 weeks therefore final exam grade is dependent variable.

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200ml of 0.1M tris-H with 732ml water and 68ml of 0.1M NaOH

The Food and Drug Administration has approved THAM, a rarely used buffer, for the treatment of metabolic acidosis related to cardiac bypass surgery and metabolic acidosis related to cardiac arrest.

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the question you are looking for is

Tris-hydroxymethyl aminomethane (TRIS) is widely used for the preparation of buffers in biochemical research. Shown here is the structure of TRIS in its protonated form: Its acid dissociation constant, pKa, is 8.32 x10-9 M. You have available at your lab bench a 0.1 M solution of TRIS in its protonated form, 0.1 Msolutions of HCl and NaOH, and ample distilled water. Describe the preparation of a 1 L solution of 0.02 M TRIS buffer, pH 7.8.

a. The smell of burnt food travels through the houses- Because the particles are really heated up and have a lot of kinetic energy, which causes them to move quickly, the stench of burnt food permeates the entire house.

b. When two solids are placed on top of each other, they do not mix-  Because they have clear boundaries and a definite shape, two solids stacked on top of one another do not mix.

c. Pumping up your bike tires gives a smooth ride- Because the tire's air pressure is what maintains it in place. Even though the tires appear to be firm when you push on them with your palm, they actually have a lot of give as the vehicle's weight shifts and it bounces around the road.

d. Smokers can cause lung damage in other people- The heart and blood arteries are impacted by secondhand smoke, which raises the risk of suffering a heart attack. The risk of developing and passing away from heart disease rises when people are exposed to secondhand smoke.

e. Heating gas in a closed container will increase its pressure- When gases in containers are heated, the average speed of their molecules increases. They consequently strike the container walls more frequently, more forcefully, and with greater force. Therefore, when the gas's temperature rises, it is under more pressure.

f. Poisonous gasses from a factory chimney can affect a large area- manufacturing chimney smoke, and power plant emissions all contribute to air pollution. Acids are created when poisonous gases, like sulfur dioxide, combine with rain and mist. A large area of plants are killed when acid rain occurs.

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Answer:

D

Explanation:

molecules have potential energy and kinetic energy.

Tempreture is defined as the average kinetic energy and internal energy is PE+KE. Pptential energy in particles or molecules is just there position relative to one another. A gas which has seperated particles will have a greater potential energy than a solid/liquid.

Answer:

4.5 written in scientific notation is 4.5×100 4.5 × 10 0 .

The only exponent number that will produce 1 as the value of the number is 0.

Explanation:

The the numbers of all the lab rules that would directly apply to this situation are discussed below.

A microscope is a laboratory equipment that is made up of lens which helps to magnify an object under investigation for study and observations.

A prepared slide is a slide that has undergone different staining procedures and is ready to be view under the microscope.

To make an efficient use of a microscope, the following laboratory rules needs to be followed:

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Making new compounds for high-speed tires is best done by the physical chemist

Chemical compounds are made up of atoms of different elements, joined together by chemical bonds and a chemical synthesis usually involves the breaking of existing bonds and the formation of new ones and physical chemists aim to develop a fundamental understanding at the molecular and atomic level of how materials behave and how chemical reactions occur, knowledge that is relevant in nearly every area of chemistry

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Answer:

the graph shows that the filtrated solution was acidic but when we add nh3 (base) ,acid base reaction take place and in this reaction salt and water are form by this oh-ion concentration keep on increasing and change ph from 4 to 10

Option A displays the accurate dimensional analysis for converting 14,612 mL to daL.

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