Hello!
The partial pressure of helium to keep the partial pressure of oxygen at 0,21 atm in a scuba-diver tank is
8,09 atmTo solve this question, we can use the
Dalton's Law, which states that the total pressure in a container with a mixture of gases is the sum of the partial pressures o each individual gas. For the case of this mixture the Dalton's Law is as follows:

In this equation, we need to clear for PHe, knowing that the PO₂ should be 0,21 atm, to find the required pressure of Helium:

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The origin is what makes it change
Answer:
Because it contains only two elements.
Explanation:
A binary compound is a compound made up of only two elements. Barium chloride contains:
1. Barium.
2. Chlorine.
Since Barium chloride contains only two elements, it is therefore a binary compound.
Answer:
B.
Explanation:
The complementary strand always has the opposite base that connects for example; the opposite of A is T.