I think you forgot to give the choices along with your question. I am answering the question based on my research and knowledge. "Helium effuses 0.71 times faster than hydrogen" is the statement that <span>holds true when the molar mass of hydrogen is 2.0 grams and that of helium is 4.0 grams. I hope the answer has helped you.</span>
Whitecap waves are caused by the wind, while swells are caused by surface gravity.
We need to first come up with a balanced equation:
→ 
We know that the molar ratio of hydrogen to oxygen to water now is 4:1:2.
Converting the amount of grams given to moles is as follows:
Hydrogen: 
Oxygen: 
We know now that the limiting reactant is oxygen. We can then know that the number of moles of water are produced are double the number of moles of oxygen used due to the ratio that we established at the beginning - 4:1:2.
So we now can use 6.25 moles of water as the amount produced.
Then we convert moles of water to grams:

Now we know that there are 112.59g of water produced when we start with 50g of hydrogen and 50g of water.
PV=nRT will give you the answer I think. I haven’t worked with a certain unit in that problem
Answer:
36.09% is the mass percent composition of calcium in calcium chloride
Explanation:
Mass percent is defined as one hundred times the ratio between the mass of a compound (In this case, Calcium), and the total mass of the sample:
<em>Mass Percent = Mass compound / Total mass of the sample × 100</em>
<em />
Computing the values of the problem:
Mass Percent = 0.690g / 1.912g * 100
Mass percent =
<h3>36.09% is the mass percent composition of calcium in calcium chloride</h3>