Answer:
See explanation
Explanation:
Electrons transition between energy levels in an atom due to gain or loss of energy. An electron may gain energy and move from its ground state to one of the accessible excited states. The electron quickly returns to ground state, emitting the energy previously absorbed as a photon of light. The wavelength of light emitted is measured using powerful spectrometers.
Atoms can be excited thermally or by irradiation with light of appropriate frequency.
Answer:
The concentration of the Cu²⁺ solution in the 10,0 mL volumetric flask is 5,425×10⁻³ M Cu²⁺
Explanation:
The first dilution from a 2,17M Cu²⁺ solution gives:
2,17 M Cu²⁺ ×
= <em>0,0217 M Cu²⁺solution</em>
<em />
The second dilution gives as concentration:
0,0217 M Cu²⁺ ×
= 5,425×10⁻³ M Cu²⁺ solution
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Answer:
The atomic mass (mₐ or m) is the mass of an atom. Although the SI unit of mass is the kilogram (symbol: kg), atomic mass is often expressed in the non-SI unit atomic mass unit (AMU) or unified mass (u) or dalton (symbol: Da), where 1 AMU or 1 u or 1 Da is defined as 1⁄12 of the mass of a single carbon-12 atom, at rest. The protons and neutrons of the nucleus account for nearly all of the total mass of atoms, with the electrons and nuclear binding energy making minor contributions.
Answer: a.polluted runoff into nearby ponds
Explanation:
A pure substance is a substance which cannot be separated physically or chemically. It is the same wherever found on earth. For example, pure gold is a pure substance. It will be the same whether it is found where you live or on another country. A mixture can be either homogeneous or heterogeneous. A homogeneous mixture is a mixture that looks the same throughout but is made of more than one element. An example of this would be salt and water mixture. A heterogeneous mixture is a mixture in which you can easily identify the different parts which make it up. An example of this would be pizza. Both these mixtures can be broken into different parts either physically or chemically.
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