Answer:
Technetium. It is only found in the stars.
Explanation:
Sorry, but thats all I could find for tou
The are many elements which are not present in human body. But almost all the discovered elements are there in the universe. But the one which is not present in earth and air is technetium
What is an technetium ?Technetium is the first synthesized element by man in 1937. Technetium has no stable isotopes and it is not found in earth. But it is present in stars. However, rare earth elements such as promethium , francium etc. can be prepared or observed from uranium ores.
There are many elements especially some actinides and lanthanides which are not present in earth naturally existence on starts and other planets.
Human body is made of various elements including carbon, oxygen, nitrogen, various metals like iron, zinc etc. Various enzymes contains different elements but the number of elements which are in the surroundings of human and not inside is larger.
Therefore, all the discovered elements are found in the universe and some them are not present in earth.
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Give one example of how environmental factor could influence the way a gene is expressed.
Answer:
The presence of drugs or chemicals in an organisms environment can also influence gene expression in the orgains.
(iii) Give two reasons why the electrolyte contains cryolite
Answer:
The mixture of cryolite and aluminum oxide has a lower melting point than pure aluminum oxide. This means a lower amount of energy is required to establish effective conditions for electrolysis and thus makes it more cost effective.
Explanation:
rank the crystal lattice structures in order of decreasing efficiency of space in the structure.
Rank the crystal lattice structures in order of decreasing efficiency of space in the structure.
1. Simple cubic
2. Body centered cubic
3. Face centered cubic
4. Hexegonal close packed
Tom pushes on a 50-kilogram box with a force of 25 newtons. Assuming the surface on which the box moves is frictionless, at what rate does the box accelerate?
Assuming the surface on which the box moves is frictionless, the rate at which the box accelerate is equal to 0.5 [tex]m/s^2[/tex].
Given the following data:
Mass of box = 50 kilogramForce = 25 newtons.To determine the rate at which the box accelerate, assuming the surface on which the box moves is frictionless:
Mathematically, Newton's Second Law of Motion is given by the formula;
[tex]Force = mass \times acceleration[/tex]
Making acceleration the subject of formula, we have:
[tex]Acceleration =\frac{Force}{mass}[/tex]
Substituting the given parameters into the formula, we have;
[tex]Acceleration = \frac{25}{50}[/tex]
Acceleration = 0.5 [tex]m/s^2[/tex]
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Oxygen is produced by the reaction of sodium peroxide, Na2O2 , and water.
2 Na2O2 (s) + 2 H2O(l) ---> O2(g) + 4 NaOH(aq)
Calculate the mass of Na2O2 in grams needed to form 5.20 g of oxygen.
Answer: 23.53g
Explanation:
5.2/(2x16) = 0.1625 mol
0.1625 x 2 = 0.325 mol
0.325 x (23 x 2 + 16 x 2) = 78 x 0.325 = 23.53g
2. How many MOLES of cobalt(III) sulfate are present in 4.25 grams of this compound?
moles.
Answer:
1 grams Cobalt(II) Sulfate = 0.006451787725861 mole using the molecular weight calculator and the molar mass of CoSO4.
Explanation:
An atom which has 9 protons, 8 neutrons, and 9 electrons will have an atomic mass of how many amu?
a. 6
b. 8
C. 9
d. 17
Answer:
D
Explanation:
Protons and Neutrons both have a mass of about 1 amu so you add them but electrons have a mass of 0 amu so they are left out.
Read the following chemical equations.
Reaction 1: 2KI + H2O2 2KOH + 12
Reaction 2: Cl2 + H2 → 2HCI
Which of the following statements is true for both the chemical equations?
A. I is oxidized in reaction 1 and Cl2 is oxidized in reaction 2.
B. I is reduced in reaction 1 and Cl2 is reduced in reaction 2.
C. I is oxidized in reaction 1 and Cl2 is reduced in reaction 2.
D. I is reduced in reaction 1 and Cl2 is oxidized in reaction 2.
This problem is providing two reduction-oxidation (redox) reactions in which the oxidized and reduced species can be identified by firstly setting the oxidation number of each element:
Reaction 1: 2K⁺I⁻ + H₂⁺O₂⁻ ⇒2K⁺O⁻²H⁺ + I₂⁰
Reaction 2: Cl₂⁰ + H₂⁰ ⇒ 2H⁺CI⁻
Next, we can see that iodine is being oxidized and oxygen reduced in reaction #1 and chlorine is being reduced and hydrogen oxidized in reaction #2 because the oxidized species increase the oxidation number whereas the reduced ones decrease it.
In such a way, the correct choice is C.
Learn more:
(Redox reactions) https://brainly.com/question/13978139What do you already know about gases?
Answer:
gasese molecules are always in free state
Pls help if you only know the correct answer! Thanks!!
Answer:
1. H=2, O=1
2. H=4, O=2
3. C=1, O=1
4.
a. reactants C=1, O=2
b. products C=1, O=2
5.
a. reactants H=4, O=2
b. products H=4, O=2
6
a. reactants C=1, O=1, H=4
b. products C=1, O=1, H=4
Determine the mass of O(2-) ions in 3 mol of alumina (Al2O3). Molar mass of O = 16)
Considering the rule of three and molar mass of O, the mass of O²⁻ ions in 3 mol of alumina Al₂O₃ is 96 grams.
By multiplying the number of moles by the subscripts next to each atom, you get the amount of each element present in the compound. IIf the same atom appears more than once in the compound, you must add its amounts.
So, in 1 mole of Al₂O₃, you have 2 ions of O²⁻.
Then you can apply the following rule of three: if 1 mole of the compound contains 2 ions of O²⁻, 3 moles of the compound contains how many ions of O²⁻?
[tex]amount of ions of O^{2-} =\frac{3 moles of Al_{2} O_{3} x2 ions of O^{2-}}{1mole of Al_{2} O_{3} }[/tex]
amount of ions of O²⁻= 6 ions
Being the molar mass of O 16 g/mole, this is the amount of mass that a substance contains in one mole, then the mass of O²⁻ can be calculated as:
6 x 16 g/mole= 96 grams
Finally, the mass of O²⁻ ions in 3 mol of alumina Al₂O₃ is 96 grams.
Learn more about molar mass:
https://brainly.com/question/3588290?referrer=searchResultshttps://brainly.com/question/25873251?referrer=searchResults7. Which white blood cells help to get rid of good cells that have been infected by a pathogen? *
(2 Points)
A. T cells
B. B cells
Answer:
B cells and T cells. The B cells produce antibodies that are used to attack invading bacteria, viruses, and toxins. The T cells destroy the body's own cells that have themselves been taken over by viruses or become cancerous.
Explanation:
How many sig figs are in 6.0395? Please no links-
Answer:
5 significant figures
Explanation:
The zeros as considered when they are in between or after numbers greater than zero.
Ex1: 0.005 = 1 significant figure
Ex2: 0.0050 = 2 significant figure
Ex3: 0.05500= 4 significant figure
Ex4: 5.00 = 1 significant figure
Calculate the density of sulfur dioxide gas (SO2) at 147°C and 29.9 kPa.
The density of the gas is obtained as 0.55 g/L.
We can find the density of the gas using the relation;
PM = dRT
P = pressure of the gas
M = molar mass of the gas
d = density of the gas
R = gas constant
T = temperature
Now;
P = 29.9 kPa
R = 8.314 L·kPa mol·K.
T = 147°C + 273 = 420 K
d = ?
M = 64 g/mol
Substituting values;
d = PM/RT
d = 29.9 kPa × 64 g/mol/ 8.314 L·kPa mol-1K-1 420 K
d = 1913.6/3491.88
d = 0.55 g/L
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why is it dangerous to wear contact lenses in the lab
Answer:
It is strongly recommended that students do NOT wear contacts lenses in the laboratory. Chemical vapors may penetrate the contact lens material and cause the lens to adhere to one's eye, which could be detrimental to the eye. Goggles are not vapor tight and do not completely eliminate this absorption.
2 WHAT ARE THE THREE THINGS NECESSARY TO MAINTAIN A FIRE?
Answer:
Oxygen, heat, and fuel
Explanation:
Oxygen, heat, and fuel are frequently referred to as the "fire triangle." Add in the fourth element, the chemical reaction, and you actually have a fire "tetrahedron." The important thing to remember is: take any of these four things away, and you will not have a fire or the fire will be extinguished.
Which statement best defines kinetic energy? A. kinetic energy is highest at the highest point of structure or model.
B. kinetic energy is stored in a battery.
C. kinetic energy is energy that is stored up. D. kinetic energy is the energy of motion. help me pls!!
Answer:
The answer is D. Kinetic energy is the energy of motion.
Pls mark brainliest. Hope this helped. :D
Select from the unit conversion factor options below to determine the mass in grams of 1.204 × 1024 atoms of carbon.
1 mol C/ 6.02 x 1023 atoms C, 6.02 x 1023 atoms C / 1 mol C
12 g C / 1 mol, 1 mol / 12 g C
a
12040 g
b
24 g
c
204 g
d
1.99 g
Answer:
option a is the answer
Explanation:
bye bye
How many moles of AgCl can form from 6.5 moles of Ag and abundant HCl in the equation: 2Ag + 2HCl -> 2AgCl + H2
6.5 moles of AgCl can be formed from 6.5 moles of Ag.
STOICHIOMETRY:
According to this question, silver reacts with hydrochloric acid to form silver chloride and hydrogen gas as follows:
2Ag + 2HCl → 2AgCl + H2
Based on this balanced equation, 2 moles of silver (Ag) produces 2 moles of silver chloride (AgCl).
This means that 6.5 moles of Ag will produce (6.5 × 2)/2 = 6.5 moles of AgCl.
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How did President Wilson anger civil rights advocates?
Answer:
He put segregationists in charge of federal agencies...
Explanation:
...
Answer:
He placed segregationists in charge of federal agencies.
Explanation:
Which of these is found in the energy levels of an atom?
Answer:
Electrons
Explanation:
Because the nucleas is In the middle and the Electrons surround it
20. A way to describe a chemical reaction
a. Equations
c. Molecules
b. Metals
d. Elements
NO LINKS!!!
Help . . .
Where is the magnetic field strongest?
A. closest to the wire
B. Farthest from the wire
Answer:
In general, the magnetic field is strongest close to the wire and weaker farther away. In fact, the magnetic field weakens as 1/r1/r where rr is the distance from the wire. This can change a bit depending on the length and shape of the wire. Far enough away, the magnetic field decays as 1/r21/r2 .
Answer:
Closest to the wire
Explanation:
In general, the magnetic field is strongest close to the wire and weaker farther away. In fact, the magnetic field weakens as where is the distance from the wire. This can change a bit depending on the length and shape of the wire.
Pls answer rn due tmr pls pls fast
Answer:
From bottom to top, Troposphere, Stratosphere, Mesosphere, Thermosphere, & at the top, Exosphere.
Explanation:
Which objects refract light? (Select all that apply.)
the human eye
contact lenses
a magnifying glass
concave mirrors
Match each type of reaction to its amount of potential energy. (PLEASE HELP )
please help fast thank yuo
Answer:
what is your question tell may i can help you
Answer:
decrease as we go down a group I know ionisation energy increases from left to right across the periodic table
Describe how this instrument works.
(legit this is 100pts so uhh help)
Operation
Answer:
This is a reflector telescope and in which it captures different wavelengths of light and it hits one mirror, bounces back and hits another and then is shown through the eyepiece. It captures all of the visible spectrum and some areas above and below it. These telescopes are better for seeing big picture and not the fine details in planets surfaces.
Hope this helps!
Explanation:
Answer:
This is a reflector telescope and in which it captures different wavelengths of light and it hits one mirror, bounces back and hits another and then is shown through the eyepiece. It captures all of the visible spectrum and some areas above and below it. These telescopes are better for seeing big picture and not the fine details in planets surfaces.
Hope this helps!
Explanation:
what do solid and gas-particle have in common? (not liquid )
Answer:
Solid, liquid, and gas are common states of matter. Because each particle is attached to several others, individual particles cannot move from one location to another, and the solid is rigid. A has a fixed volume but does not have a fixed shape. Liquids take on the shape of the container they are in.
Explanation:
sorry, this is what i think
A student is trying to classify an unidentified, solid gray material as a metal or a nonmetal. Which question will best help the student classify the material?.
The question that will best help the student to classify the material is; "is the material malleable or ductile?"
Generally, materials can be classified as metals or non metals. There are properties that are particular to metals and there are properties that are particular to nonmetals and these properties can be used to identify each one of the materials.
The question that will best help the student to classify the material is; "is the material malleable or ductile?" These metallic properties.
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Missing parts;
A student is trying to classify an unidentified, solid gray material as a metal or a nonmetal. Which question will best help the student classify the material? A. Is the material malleable or ductile? B. Does the material feel hard to the touch? C. Will the material float in water? D. Does the material feel rough or smooth?