Answer:
Mass of Rb-87 is 86.913 amu.
Explanation:
Given data:
Average mass of rubidium = 85.4678 amu
Mass of Rb-85 = 84.9117
Ratio of 85Rb/87Rb in natural rubidium = 2.591
Mass of Rb = ?
Solution:
The ration of both isotope is 2.591 to 1. Which means that for 2.591 atoms of Rb-85 there is one Rb-87.
For 100% naturally occurring Rb = 2.591 + 1 = 3.591
% abundance of Rb-85 = 2.591/ 3.591 = 0.722
% abundance of Rb-87 = 1 - 0.722= 0.278
84.9117 × 0.722 + X × 0.278 = 85.4678
61.306 + X × 0.278 = 85.4678
X × 0.278 = 85.4678 - 61.306
X × 0.278 = 24.1618
X = 24.1618 / 0.278
X = 86.913 amu
As another example, consider the downward force<span> of gravity that the Earth exerts on </span>you<span> (also </span>called<span> weight). In turn, </span>you<span> exert an exactly equal upward </span>force<span> on the Earth. Together, those </span>two forces<span> form an action-reaction </span>force pair<span>.</span>
Answer:
True
Explanation:
To begin with,
Hydrogen bonds are attractions that contain a force caused by the difference in charge. This is due to the positive hydrogen ions as well as slightly negative ions. Therefore, hydrogen bonds make water molecules 'sticky.' To add, the attractions between hydrogen bonds are weaker than ionic and covalent bonds but strong enough to cause them to 'stick together'
Hope this helps.
First you would multiply 5,3, and 2 to get a volume of 30. Density is mass over volume so you would then divide 129 by 30. You would get 4.3. The answer would be 4.3 g/cm^3
