The much of the sample that would remain unchanged after 140 seconds is 2.813 g
Explanation
Half life is time taken for the quantity to reduce to half its original value.
if the half life for Scandium is 35 sec, then the number of half life in 140 seconds
=140 sec/ 35 s = 4 half life
Therefore 45 g after first half life = 45 x1/2 =22.5 g
22.5 g after second half life = 22.5 x 1/2 =11.25 g
11.25 g after third half life = 11.25 x 1/2 = 5.625 g
5.625 after fourth half life = 5.625 x 1/2 = 2.813
therefore 2.813 g of Scandium 47 remains unchanged.
Answer:
See explanation
Explanation:
The molecular mass is the sum of the relative atomic masses of all the atoms in the molecule.
The relative atomic mass of reactants and products are calculated as follows;
Benzoic acid is C7H6O2 hence the molar mass of benzoic acid is ;
7(12) + 6(1) + 2(16) = 84 + 6 + 32 = 122.0 g/mol
Methyl benzoate is C8H8O2
8(12) + 8(1) + 2(16) = 96 + 8 + 32 = 136.0 g/mol
Answer:
ionic
Explanation:
Ionic bonds exist between Ca and F ions in CaF₂. Ionic bonds are interatomic bonds formed by the transfer of electrons from one atom to the other.
The donor atom here is Ca and it has two valence electrons. Fluorine is the receiving atom with 7 electrons in its outermost shell.
Ca would give one each of its two outermost electrons to the fluorine atoms to complete their octet. Ca ion would now resemble Argon and the flourine atoms would look more like Neon atoms.
This is an ionic bond
