Answer:
²³⁰₉₀Th
Explanation:
X → ²²⁶₈₈Ra + ⁴₂He
The given equation shows the alpha emission. When He particle emit the original atom convert into the atom having mass number less than 4 and atomic number less than 2 as compared to parent atom the starting atom. It means the parent atom is ²³⁰₉₀Th.
Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. Which is also called helium nuclei. When atom undergoes the alpha emission the original atom convert into the atom having mass number less than 4 and atomic number less than 2 as compared to parent atom the starting atom.
Alpha radiations can travel in a short distance.
These radiations can not penetrate into the skin or clothes.
These radiations can be harmful for the human if these are inhaled.
These radiations can be stopped by a piece of paper.
₉₂U²³⁸ → ₉₀Th²³⁴ + ₂He⁴ + energy
Forming a hypothesis
Explanation:
The step in an investigation which involves the prediction of results is the stage of forming of a hypothesis.
- A hypothesis is a stage in scientific investigation that follows shortly after asking a simple scientific question.
- Hypothesis is simply a scientific guess that is logical in nature.
- It presents a problem in a manner in which the problem is stated, the cause and the likely outcome can be predicted.
- After a hypothesis formulation, the experiment is conducted and results of findings weighed against the predictions of the statement.
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Hypothesis brainly.com/question/3418951
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The piece of unknown metal is in thermal equilibrium with water such that Q of metal is equal to Q of the water. We write this equality as follows:
-Qm = Qw
Mass of metal (Cm)(ΔT) = Mass of water (Cw) (ΔT)
where C is the specific heat capacities of the materials.
We calculate as follows:
-(Mass of metal (Cm)(ΔT)) = Mass of water (Cw) (ΔT)
-68.6 (Cm)(52.1 - 100) = 42 (4.184) (52.1 - 20)
Cm = 1.717 -----> OPTION C<span>
</span>
Molar mass Na2SO4 = <span>142.04 g/mol
142.04 g -------------- 6.02x10</span>²³ atoms
?? g ------------------ 7.4x10²³ atoms
142.04 x ( 7.4x10²³) / 6.02x10²³
=> 174.60 g