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
Answer:
CLEANER
Explanation:
Independent variable is the variable in an experiment that is changed or manipulated by the experimenter in order to bring about a measurable response.
In this question, Marie notices that the current cleaner she is using on her shower is not cutting through the hard water build-up that has accumulated. She decides to purchase 3 other cleaners to see if one of them will do a better job of cutting through the stains. The CLEANERS being changed in this experiment is the INDEPENDENT VARIABLE.
Thermal, electrical, chemical, nuclear, and electromagnetic energy. (just gave you more than two just incase)
A good first step is writing the amount in terms of ml.
19.2 gallons = 72.68 L = 72680 ml
that would mean it weighs 0.749*720680g = 54437.32ml = 54.437 L
hope that helps :)
7 count the dots in the middle for you answer and if not it’s 3