The transfer of heat energy that does not require matter of any type is radiation
Energy that emanates from a source and moves through space at the speed of light is referred to as radiation. This energy has wave-like qualities and is accompanied by an electric field and a magnetic field. Radiation may also be referred to as electromagnetic waves. electromagnetic waves or particles are emitted as energy.
Radon gas, cosmic rays from space, x-rays used in medicine, and radiation emitted by radioactive isotopes are examples of common sources of radiation. Radiation is the process of transferring thermal energy without the need for any kind of materials.
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2. Cr
3. Mg
4. Pb
Answer : The correct option is, (2) Cr (Chromium)
Explanation :
The reactivity series of metal are arranged of the reactivity from the highest to the lowest. Reactivity series is used to determine the products of the single displacement reactions. In the single displacement reaction, the most reactive metal displaces the least reactive metal.
From the given reactivity series we conclude that there are two metal (Mg and Cr) are more reactive metal than the Ni and there are two metal (Pb and Cr) are less reactive metal than the Zn. So, the Cr (Chromium) is the metal which is more active than Ni and less active than Zn.
Hence, the correct option is, (2) Cr
b) phosphorus
c) aluminum
d) boron
Answer:
33.21% is the right answer.
Explanation:
0.04720 L * 0.02240 mol / L = 1.0573*10-3
mol Fe+2 = 1.0573* 10-3 mol = 5.2864*10-3
mass of Fe= 5.2864 * 10-3 = 0.29522g
% of Fe in sample = 0.29522 g Fe / 0.8890 g of sample * 100 = 33.21%
The number of moles of MnO4– added to the solution is 0.00106 mol. The moles of Fe2+ in the sample is 0.00530 mol. The grams of iron in the sample is 0.296 g and the percentage of iron in the sample is 33.33%.
The titration reaction between Fe2+ and MnO4– in acid solution is as follows: 5Fe2+ + MnO4– + 8H+ → 5Fe3+ + Mn2+ + 4H2O. Firstly, we can calculate the number of moles of MnO4– added to the solution using the formula volume X molarity. That is 0.0472 L X 0.02240 M = 0.00106 mol MnO4–. According to the balanced redox reaction, one mole of MnO4– reacts with five moles of Fe2+. Therefore, the moles of Fe2+ in the sample is 0.00106 mol MnO4– X 5 = 0.00530 mol Fe2+.
Next, we calculate the grams of iron in the sample. The molarmass of iron is approximately 55.85 g/mol, thus the grams of iron in the sample are 0.00530 mol Fe2+ X 55.85 g/mol = 0.296 g Fe2+. Finally, we find the percentage of iron in the sample by mass = (mass of iron in the sample / total mass of the sample) X 100%. Therefore, the percentage is (0.296 g / 0.8890 g) X 100% = 33.33%.
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(2) C, N, Ne, Ar (4) Na, Zn, As, Sb
(1) Be, Si, Cl, Kr is the list of elements that includes a metal, a metalloid, a nonmetal, and a noble gas.
Shiny, malleable, ductile, and good at transferring heat and electricity are the characteristics of a metal. Metal beryllium (Be) is one.A substance with characteristics of both metals and nonmetals is referred to as a metalloid or semi-metal. Metalloid silicon is known as Si.
An element without metallic characteristics is referred to as a nonmetal. At ambient temperature, nonmetals are frequently gases or brittle solids. A nonmetal is chlorine (Cl).An element in group 18 of the periodic table that is inert and has a difficult time forming chemical compounds is referred to as a noble gas. A noble gas is krypton (Kr).
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(1) Energy is emitted.
(2) Energy is absorbed.
(3) The number of electrons decreases.
(4) The number of electrons increases.
Answer: The correct option is (1).
Explanation:
Whenever an atom in an excited state returns back to its ground state the energy is emitted out in the form of the radiation and the value of energy emitted can be determined by using the expression:
Where E = Energy of the radiation in joules
h = Planck's constant =
= Wavelength of the radiation in meters.
a. True
b. False