Answer:
Physical Change
Explanation:
The bush is changing shapes, not changing what it is.
The sideways and downward movement of the edge of a plate of the earths crust into the mantle beneath another plate
The variable X is the effective nuclear charge, and it remains constant down a group.
Discussion:
The effective nuclear charge is referred to as the actual amount of positive (nuclear) charge experienced by an electron in a polyelectronic atom.
The effective nuclear charge experienced by an electron is otherwise called the core charge.
It is mathematically evaluated as the difference in the atomic number and the core electrons. and since elements in the same group have equal number of Valence electrons, the effective nuclear charge is constant down the group.
Read more on effective nuclear charge:
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Answer:
There are 10.0 moles of beryllium oxide in a 250 grams sample of the compound.
Explanation:
We can calculate the number of moles (η) of BeO as follows:
Where:
m: is the mass = 250 g
M: is the molar mass = 25.0116 g/mol
Hence, the number of moles is:
Therefore, there are 10.0 moles of beryllium oxide in a 250 grams sample of the compound.
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Answer:
The mole is the SI unit for amount of a substance.
Explanation:
Just like the dozen and the gross, it is a name that stands for a number. There are therefore 6.02 × 10 23 water molecules in a mole of water molecules.
