A B C these are the answers hopes this help <3
A. how the Moon's appearance changes
Explanation:
Descriptive investigation use very careful observations and measurements to develop findings.
Most geologists, meteorologists and astronomers use descriptive investigation to develop their findings.
- Since most of their subject matter is inaccessible.
- Descriptive investigation is used for indirectly making inquiries
- It involves the development of an inquiry without formulating any hypothesis.
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Answer:
C(graphite) → C(diamond), ΔH = - 0.45 kcal
CH4 + 2O2 → CO2 + 2H2O + 212,800 cal
Explanation:
C(graphite) → C(diamond), ΔH = - 0.45 kcal
CH4 + 2O2 → CO2 + 2H2O + 212,800 cal
These reactions are exothermic reaction because heat is evolved.
The energy changes occur during the bonds formation and bonds breaking.
There are two types of reaction endothermic and exothermic reaction.
Endothermic reactions:
The type of reactions in which energy is absorbed are called endothermic reactions.
In this type of reaction energy needed to break the bond are higher than the energy released during bond formation.
For example:
C + H₂O → CO + H₂
ΔH = +131 kj/mol
it can be written as,
C + H₂O + 131 kj/mol → CO + H₂
Exothermic reaction:
The type of reactions in which energy is released are called exothermic reactions.
In this type of reaction energy needed to break the bonds are less than the energy released during the bond formation.
For example:
Chemical equation:
C + O₂ → CO₂
ΔH = -393 Kj/mol
it can be written as,
C + O₂ → CO₂ + 393 Kj/mol
Answer: [Kr] 5s1 4d10 silver
[Xe] 6s2 4f14 5d7 Iridium
[Ar] 4s2 3d10 4p4 selenium
[Kr] 5s1 4d4 niobium
[Xe] 6s1 4f14 5d10 gold
[Kr] 5s2 4d10 5p4 tellurium
Explanation:
Selenium and tellurium will have the same properties because they both belong to group 16 in the periodic table.
Silver and gold will have the same properties because they both belong the group 11 in the periodic table.
Elements having the same outermost shell configuration show similar properties since chemical reactions occur by loss or gain of electrons. This loss or gain is determined by the number of electrons occupying the outermost shell. Elements in the same group have the same outermost shell electron configuration and similar properties.