Hydrogen and oxygen are different elements ...
but when two or more elements combine... it is known as a compound.. hence hydrogen and oxygen together form a compound
I think the correct answer would be the first option. As the hiker reaches the top of the mountain, the plastic bag would, most likely, expand. Before starting, the plastic bag would have a certain amount of gas particles inside. As the you hike, the pressure would decrease causing for the gas molecules to reestablish equilibrium thus pushing the bag outwards. In other words, expanding the bag. Also, base from the ideal gas equation, PV = nRT, at constant temperature and number of moles, pressure and volume are inversely related. Thus, as the pressure decreases, the volume of the system would increase accordingly.
Answer: Each ion is surrounded by water molecules
Explanation: The ions are surround by the water molecules which act as a barrier around the ions and prevent the recombination of ions. The ions are said to be hydrated.
Answer:

Explanation:
Helo,
In this case, the pressure must be computed as follows:

Which is using the density of mercury (13.6 g/mL) and its height, thus, we obtain (using the proper units):

Best regards.
Answer:
it says the answer is variation