Answer:
Explanation:
Our 
sample yielded 1g of 
and 16g of 
, but our unknown sample yielded 2 times as much for the same amount of .
What does this mean? that the H:O proportion for the unknown sample is twice the H:O proportion for the sample.
What is the H:O proportion for the sample? As we can see from its formula, it's 1:1, therefore the proportion for the unknown formula must be 2:1.
That means, two H atoms for every O atom. We could write that as: 
and you should recognize that formula, for it is one of the most common compounds on earth, Water.
Answer:
71 Ga has a naturally abundance of 36%
Explanation:
Step 1: Given data
Gallium has 2 naturally occurring isotopes: this means the abundance of the 2 isotopes together is 100 %. The atomic weight of Ga is 69.72 amu. This is the average of all the isotopes.
Since the average mass of 69.72 is closer to the mass of 69 Ga, this means 69 Ga will be more present than 71 Ga
Percentage 69 Ga> Percentage 71 Ga
<u>Step 2:</u> Calculate the abundance %
⇒Percentage of 71 Ga = X %
⇒Percentage of 69 Ga = 100 % - X %
The mass balance equation will be:
100*69.72 = x * 71 + (100 - x)*69
6972 = 71x + 6900 -69x
72 = 2x
x = 36 %
71 Ga has a naturally abundance of 36%
69 Ga has a naturally abundance of 64%
The formula for water is H2O so there would have to be two Hyrdogens and one oxygen. Therefore it would be 4g of Hydrogen and 16g of Oxygen leaving you with 20g.
The answer is D.
Hope this helps :) ~
