Answer:
Associative Evidence
Explanation:
According to the authors, the most effective means of developing associative evidence are instrumental chemistry, microscopy, photomacrography, other optical methods, and morphology. It is used to provide the link between and evidence and individual involved in a crime.
Answer:
The chlorine gas and potassium bromide solution react to form liquid bromine and potassium chloride solution.
Explanation:
Chemical equation:
Cl₂(g) + KBr (aq) → KCl (aq) + Br₂(l)
Balanced chemical equation:
Cl₂(g) + 2KBr (aq) → 2KCl (aq) + Br₂(l)
This equation showed that the chlorine gas and potassium bromide solution react to form liquid bromine and potassium chloride solution.
Chlorine is more reactive than bromine it displace the bromine from potassium and form potassium chloride solution.
The given equation is balanced and completely hold the law of conservation of mass.
According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.
Explanation:
This law was given by french chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.
1-It has to be 3 Fe and not Fe3.
2-The oxygens aren't balanced
Balanced equation:
3Fe+4H2O---->Fe3O4+4H2
Electrons in an atom can be classified as core electrons and valence electrons. Valence electrons are those electrons which are present in valence shell and participates in bond formation. While, Core electrons are all remaining electrons which are not present in valence shell, hence not take part in bonding.
Atomic number of Selenium (Se) is 34 hence it has 34 electrons with following electronic configuration;
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁴
From electronic configuration it is found that the valence shell is 4, and the number of electrons present in valence shell are 6. So,
Core Electrons = Total Electrons - Valence Electrons
Core Electrons = 34 - 6
Core Electrons = 28
Result:
There are 28 core electrons in Selenium.
