Answer:
This element is Rubidium (Rb) and has an average atomic mass of 85.468 u
Explanation:
The average mass of an element is calculated by taking the average of the atomic masses of its stable isotopes.
The enitre atomic mass = 100 % or 1
⇒ this consists of X-85 with 72.17 % abundance with atomic massof 84.9118 g/mol
72.17 % = 0.7217
⇒ this consists of X-87 with 27.83 % abundance with atomic mass of 86.9092 g/mol
27.83 % = 0.2783
To calculate the mass of this isotope we use the following:
0.7271 * 84.9118 + 0.2783 * 86.9092 =85.468 g/mol
This element is Rubidium(Rb) and has an average atomic mass of 85.468 u
Answer:
A saturated solution can become supersaturated when it is cooled. The solubility of solid solutes in liquid solvents increases as the solvent is warmed up. For example, you can dissolve more sugar in warm water as opposed to cold water.
Answer: 1.3% many crosslinks as isoprene units,
Explanation:
Given:
mass pf natural rubber= 200.0g
mass of sulphur = 4.8g
molar mass of sulphur =32g/mol
molar mass of isoprene = C5H8=( 12x5) +(1x8)= 68g/mol
Solution: we first find no of moles present in each using
no of moles = 
Isoprene: 200.0g x [1mole / 68g] = 2.94moles.
Sulfur: 4.8g x [1mole / 32g] x [1 mole crosslinks / 4 moles S] = 0.0375 moles crosslinks.
to find % crosslinked units, we have
0.0375 / 2.94 = 1.3% as many crosslinks as isoprene units,
According to the equation, the ratio of the reactant Cu and product CuO is 2:2, thus 1:1. Therefore to produce 2.44 mol CuO, 2.44 mol Cu is required. The molecular weight of Cu is 64. So the mass of Cu that is required to produce 2.44mol CuO is 2.44mol * 64 g/mol = 156.16 g.
