Answer:
the anwser isn't in the choices
Explanation:
H=MC(change of temp.)
M=mass of water=250g
C=specific heat of water = 4.186 j/g
change in temperature is 121-40= 81
H= 250x4.186x81=84766.5J
Answer:
\left \{ {{y=206} \atop {x=82}}Pb \right.
Explanation:
isotopes are various forms of same elements with different atomic number but different mass number.
Radioactivity is the emission of rays or particles from an atom to produce a new nuclei. There are various forms of radioactive emissions which are
- Alpha particle emission \left \{ {{y=4} \atop {x=2}}He \right.
- Beta particle emission \left \{ {{y=0} \atop {x=-1}}e \right.
- gamma radiation \left \{ {{y=0} \atop {x=0}}γ \right.
in the problem the product formed after radiation was Pb-206. isotopes of lead include Pb-204, Pb-206, Pb-207, Pb-208. they all have atomic number 82. which means the radiation cannot be ∝ or β since both radiations will alter the atomic number of the parent nucleus.
Only gamma radiation with \left \{ {{y=0} \atop {x=0}}γ \right. will produce a Pb-206 of atomic number 82 and mass number 206 , since gamma ray have 0 mass and has 0 atomic number.equation is shown below
\left \{ {{y=206} \atop {x=82}}Pb\right ⇒ \left \{ {{y=206} \atop {x=82}}Pb\right + \left \{ {{y=0} \atop {x=0}}γ\right.
Thus the atomic symbol is \left \{ {{y=206} \atop {x=82}}Pb\right
The loss or gain of electrons
Explanation:
The loss or gain of electrons determines if an atom will become a cation or anion.
A cation is a positively charge ion
An anion is a negatively charged ion.
In an atom, we have sub-atomic particles:
Protons are the positively charged particles
Electrons are negatively charged
Neutrons carry no charges
Only electrons can be lost or gained in chemical processes that forms cations and anions.
When a neutral atom gains electron, it has more electrons than protons. This makes it negatively charged and we call it an anion.
When a neutral atom loses an electron, the number of protons is more. We call it a cation.
Learn more:
Cations brainly.com/question/4670413
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This is Bohrs model for potassium
Answer: Option (c) is the correct answer.
Explanation:
Wood is a mixture of different substances. Primarily it consists of cellulose, lignin, water etc.
When we heat wood then all these substance oxidize into the atmosphere even before they could melt.
Whereas iron, sodium chloride and ethanol all are the substances which can melt at any temperature.
Thus, we can conclude that out of the given options, wood, a mixture of different substances is a material that does not melt at any temperature.
