magnesium trace element which of the following is a trace element, required only in small amounts by most living things?

Wilhelm Roentgen discovered that a cathode-ray beam striking a glass surface produced a new type of radiation that he named X-rays.

Roentgen was experimenting with cathode rays in a vacuum tube when he noticed that a fluorescent screen in his lab started to glow even though it was not in the direct path of the cathode rays. He determined that a new type of radiation was being emitted from the tube, which he later discovered had the ability to pass through solid objects like human tissue.

Roentgen's discovery of X-rays revolutionized the field of medicine and led to the development of medical imaging techniques like X-ray machines, CT scans, and MRI scans.

The discovery of X-rays had far-reaching implications beyond just medicine. It laid the foundation for a new field of science known as radiology and enabled scientists to study the internal structures of objects without destroying them. X-rays also helped in the development of radiotherapy and cancer treatment by providing a non-invasive method for locating tumors within the body. Today, X-rays are still widely used in the medical field and other industries for various purposes.

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Answer:

nucleus

Explanation:

Answer:

The nucleus

Explanation:

The nucleus can be thought of as the brains of a cell.

-CancerQuest

Answer:

See explanation

Explanation:

1) With the advent of the quantum theory came the idea that the path of a moving electron can not be exactly determined. We can only talk about the probability of finding the electron within a given region in space.

2) Using the De Broglie's relation;

λ = h/mv

Where;

λ = wavelength

h = Plank's constant

m = mass

v = velocity

λ = 6.6 * 10^-34/2.05 x 10^7 * 7.85 x 10^3

λ = 4.1 * 10^-25 m

The new freezing point of the solution is 1.09 °C.

Based on the given information, the freezing point of pure water is 0.0 °C, and the freezing point changes by 1.09 °C. To find the new freezing point of the solution, we need to add the change in freezing point to the freezing point of pure water.

0.0 °C + 1.09 °C = 1.09 °C

Therefore, the new freezing point of the solution is 1.09 °C.

When performing calculations with significant figures, it's important to consider the rule for addition and subtraction. According to this rule, the result should be rounded to the least number of decimal places among the values being added or subtracted. In this case, both the freezing point of pure water (0.0 °C) and the change in freezing point (1.09 °C) have one decimal place. Thus, the final answer is also rounded to one decimal place, resulting in a new freezing point of 1.1 °C.

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Explanation:

(P1V1)/T1=(P2V2)/T2

(15X5)/297=(p2x2.5)/473

p2=47.78cmHg

To calculate the pH of an unbuffered 0.010 M acetic acid solution, we first need to find the concentration of H+ ions using the Ka expression: Ka = [H+][A-]/[HA]. The Ka of acetic acid is 1.8 x 10^-5. In this case, the initial concentration of acetic acid ([HA]) is 0.010 M, and we assume the change in H+ and A- concentrations is 'x.' The equation becomes:

1.8 x 10^-5 = (x)(x)/(0.010 - x)

Solving for 'x' gives the concentration of H+ ions, and then we can find the pH using the formula pH = -log10[H+].

For the buffered acetic acid solution with 0.004 M H+ added, the pH won't change significantly due to the buffer capacity. The pH will remain close to the pKa of the acetic acid, which is -log10(1.8 x 10^-5).

For the unbuffered acetic acid solution with 0.004 M H+ added, we need to account for the additional H+ ions in the pH calculation, so the [H+] will be the sum of the ions from the acetic acid dissociation and the added H+ ions.

For the buffered acetic acid solution with 0.004 M OH- added, the pH will also remain close to the pKa of acetic acid due to the buffer capacity. The buffer system will neutralize the added OH- ions, preventing significant changes in the pH.

In summary, buffered solutions maintain a stable pH when small amounts of acids or bases are added, whereas unbuffered solutions experience significant pH changes.

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Answer:

to collect liquid ethanol and leave ethene as a gas because ethanol has hydrogen bonds    

Explanation:

The chemist would be lesser than the temperature of the mixture as to collect the liquid ethanol and then leave ethene as a gas since the ethanol is a bond that should be hydrogen. Also -OH that available in the ethanol would be responsible for the hydrogen bonds also it is the main and significant molecular forice

So as per the given situation the above represent the answer

Answer:

to collect liquid ethanol and leave ethene as a gas because ethanol has hydrogen bonds    

Explanation:

Strong base  dissociates 90% into metal ions and hydroxide ions in solution.

According to the Arrhenius concept, base is defined as a substance which yields hydroxyl ions on dissociation.These ions react with the hydrogen ions of acids to produce salt in an acid-base reaction.

Bases have a pH higher than seven as they yield hydroxyl ions on dissociation.They are soapy in touch and have a bitter taste.According to the Lowry-Bronsted concept, base is defined as a substance which accepts protons .Base react violently with acids to produce salts .Aqueous solutions of bases can be used to conduct electricity .They can also be used as indicators in acid-base titrations.

They are used in the manufacture of soaps,paper, bleaching powder.Calcium hydroxide ,a base is used to clean sulfur dioxide gas while magnesium hydroxide can be used as an antacid to cure acidity.

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"To insure proper operation of an oxygen cylinder regulator, make sure no oil residue is present" is true because oil residue can compromise the functioning of an oxygen cylinder regulator.

Explanation: It is true that to ensure proper operation of an oxygen cylinder regulator, it is important to make sure that no oil residue is present. Oxygen cylinders contain highly concentrated oxygen that can react violently with oil or grease, leading to combustion or explosions. Oil residue can contaminate the regulator and pose a significant safety risk.

Therefore, it is crucial to keep oxygen cylinders and their regulators free from any oil or grease to maintain safe and proper functioning.

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Answer:

Aluminium Can not rust (Can't rust also meaning Corrode)

Because it's surface is protected by aluminium Oxide which stops the metal below from coming in contact with the air (which contains Oxygen) Unlike rust, which can flake off the surface of iron and steel objects, the layer of aluminium oxide does not flake off.

Corrode

destroy or damage (metal, stone, or other materials) slowly by chemical action.

Answer:

The correct option is A Hydrogen

Explanation:

The correct option is A Hydrogen

Iron on reaction with hydrochloric acid, replaces the hydrogen from the acid and forms ferrous chloride. Hydrogen gas is evolved during the reaction in the form of bubbles.

Fe (s) + 2HCl (aq) → FeCl2 (aq) +H2 (g)

Answer:

180

Explanation:

proton = 80

electron = 80

neutron = 100

Note:- the atomic number of an element is the number of protons/electrons in the atomic shell

(protons = electrons)

Mass number = number of protons/electrons + number of neutrons

MN= NP+ NN

MN = 80 + 100

MN= 180

I HOPE THIS HELPS

Molecules in a mixture can attract each other due to their shared physical properties, such as mass, charge, and polarity.

When ethanol is present in a mixture, it interacts with other molecules due to its polar nature. This means that it will form hydrogen bonds with molecules that have hydrogen-bonding groups, such as oxygen, nitrogen, and fluorine.

The picture below illustrates the interactions between the components of the mixture and the solvent, ethanol.

A chemical mixture is a combination of two or more different chemical substances that are not chemically bonded together. A mixture is different from a chemical compound in that the substances in a mixture are not chemically combined, and can be separated easily.

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Answer:

Explanation:

3

Significant figures are the number of digits that add to the correctness of a value, frequently a measurement. The following numbers are three significant digits 876000, 1.20 x 10⁵, and 8.77 x 10⁻⁴.

The number of significant single digits (0 to 9 inclusive) in the coefficient of expression in the scientific notation is referred to as "significant figures" (SF). The expression's number of significant figures reveals the engineer's or scientist's level of assurance or precision when expressing a quantity.

When a number is rounded off, its value is maintained but is brought closer to the next number, simplifying the number. The crucial figures are preserved when numbers are rounded off.

The following numbers are rounded off:

1. 876000

2. 1.20 x 10⁵

3. 8.77 x 10⁻⁴

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Answer:

540.47g approximately

Explanation:

No. of moles in Na₂CO₃ = 5.4 moles

Mole ratio of Na₂CO₃ : CaCO₃ = 1:1

No. of moles in CaCO₃ = 5.4 moles

Mass of CaCO₃ = 5.4 × 100.0869

= 540.46926g

Endothermic reactions are those in which heat is absorbed from the surroundings.

They are reactions in which heat is absorbed from the surrounding, making the reaction vessels become colder.

It is unlike exothermic reactions in which heat is released into the surrounding, making the reaction vessel to be warmer.

For endothermic reactions, the enthalpy change is always positive because heat is absorbed. It is however negative for exothermic reactions because heat is evolved.

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Answer:

B. 6CO2 + 12H2O + energy =  C6H12O6 + 6O2 + 6H2O

Explanation:

D- A molecule

Explanation:

(Apex)

Answer:

Explanation:

The reactivity of fluorine can be explained from molecular orbital theory with the calculation of the bond order.

The molecular orbital theory is assigned to explain the movement of the electrons in the bonding and anti-bonding orbitals.

The number of atom in the bonding and anti-bonding atomic orbits results in the elucidation of the bond order for the element.

The bond order and reactivity are inversely proportional to each other. The higher bond order depicts the presence of stronger bonds between the molecules and lower reactivity.

The bond order of fluorine atom is elucidated from the molecular orbital theory. The bond order of fluorine atom is 1, that explains the high reactivity of fluorine.

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The given question is incomplete. The complete question is:

A gas has a volume of 590 ml at  a temperature  of \(0^0C\).What volume will the gas occupy at \(30.0^0C\). Which gas law is this?

Answer: 655 ml , Charle's Law

Explanation:

To calculate the final volume of the system, we use the equation given by Charles' Law. This law states that volume of the gas is directly proportional to the temperature of the gas at constant pressure.

Mathematically,

\(\frac{V_1}{T_1}=\frac{V_2}{T_2}\)

where,

\(V_1\text{ and }T_1\) are the initial volume and temperature of the gas.

\(V_2\text{ and }T_2\) are the final volume and temperature of the gas.

We are given:

\(V_1=590ml\\T_1=0^oC=(0+273)K=273K\\V_2=?\\T_2=30.0^0C=(30+273)K=303K\)

Putting values in above equation, we get:

\(\frac{590}{273}=\frac{V_2}{303}\\\\V_2=655ml\)

Thus the volume at \(30.0^0C\) is 655 ml

the answer would be iron. divide mass by volume to get density.

Answer:

B. Iron

Explanation:

Correct

Answer:

The answer is

Explanation:

The acceleration of an object given it's mass and it's net force can be found by using the formula

\(acceleration = \frac{force}{mass} \\ \)

From the question

force = 60 N

mass = 12 kg

So we have

\(acceleration = \frac{60}{12} \\ \)

We have the final answer as

Hope this helps you

Answer:

Electronegativity is the measure of the ability of an atom to attract electrons to itself. So, higher electronegativity helps atoms take more control over shared electrons creating partial negative regions and partial positive regions which result in dipoles that cause polarity.

Explanation:

(pls mark me brainliest)

Answer:Electronegativity is the measure of the ability of an atom to attract electrons to itself. ... So, higher electronegativity helps atoms take more control over shared electrons creating partial negative regions and partial positive regions which result in dipoles that cause polarity.

Explanation:hope this helps and if im wrong im sorry :)

When a water molecule is split, part of it is which used to make fuels is : a.) the electrons and protons from the hydrogen.

The water molecules break down into hydrogen and oxygen at the atomic level during thermolysis. For instance, around 3% of all H2O dissociates into different combinations of hydrogen and oxygen atoms at 2200 °C, primarily into H, H2, O, O2, and OH.

Water splitting is the chemical reaction where water is broken down into oxygen and hydrogen: 2 H2O → 2 H2 + O2

Efficient and economical water splitting could be a technological breakthrough that could underpin hydrogen economy, based on green hydrogen. A version of water splitting occurs in photosynthesis also but hydrogen is not produced.

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he specific heat of a 26 grams sample of metal at 82.25 degrees is 0.971 J/g°C.

Given that

Initial temperature of liquid water = 24.0°C

Final temperature of water = 28.34°C

Final temperature of metal = 28.34°C

Mass of water = 75.0 grams

Mass of metal = 26.0 grams

Specific heat capacity of water = 4.18 J/g°C

To find the specific heat of the metal:

Mathematically, heat capacity or quantity of heat is given by the formula;

Where:

Q represents the quantity of heat.

m represents the mass of an object.

c represents the specific heat capacity.

∅ represents the change in temperature.

Heat lost by water = Heat gained by metal.

75 ( 4.18) ( 28.34 - 24) = 26c (82.25 - 28.34)

313.5 ( 4.34) = 26 ( 53.91) c

1360.59 = 1401.66 c

c = 1360.59 / 1401.66

Specific heat of metal, c = 0.971 J/g°C.

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Answer:

The answer is 80!

Explanation:

A prism is a three dimensional solid object in which the two ends are identical. It is the combination of the flat faces, identical bases and equal cross sections. The volume of the prism is 819 cm³.

A prism is a polyhedron with two parallel congruent faces called the bases that are polygons. The volume of a three dimensional solid is the amount of space it occupies. The volume is measured in cubic units. The volume can be denoted in m³, cm³, ft³, etc.

The volume of a prism is the area of the base times the height. The equation used to calculate the volume is:

Volume = Base area × Height

Here the rectangle has 9cm length and 7cm width. Then the area is:

Area = 9 × 7 = 63 cm²

The height of prism = 13 cm

Then the volume is:

V = 63 × 13 = 819 cm³

Thus the volume of the prism is 819 cm³.

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Your question is incomplete most probably your full question was

What is volume of the rectangular prism with length 9cm, width 7cm and height  13 cm?

Answer:

Anything that has less density than water will float on water.

Explanation:

Come on! It's basic knowledge!

The size of volumetric flask that would be useful in diluting 100 ml of a 3.0 M solution of sucrose to make a 0.60M solution is 500mL.

The volume of a solution can be calculated by using the following expression;

C1V1 = C2V2

Where;

3 × 100 = V2 × 0.60

300 = 0.6V2

V2 = 300 ÷ 0.6

V2 = 500mL

Therefore, the size of volumetric flask that would be useful in diluting 100 ml of a 3.0 M solution of sucrose to make a 0.60M solution is 500mL.

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Explanation:

Magnets actually do both attract and repealto each other. Magnets repeal similar poles where as attract opposite poles.