Answer:
the volume occupied by 3.0 g of the gas is 16.8 L.
Explanation:
Given;
initial reacting mass of the helium gas, m₁ = 4.0 g
volume occupied by the helium gas, V = 22.4 L
pressure of the gas, P = 1 .0 atm
temperature of the gas, T = 0⁰C = 273 K
atomic mass of helium gas, M = 4.0 g/mol
initial number of moles of the gas is calculated as follows;

The number of moles of the gas when the reacting mass is 3.0 g;
m₂ = 3.0 g

The volume of the gas at 0.75 mol is determined using ideal gas law;
PV = nRT

Therefore, the volume occupied by 3.0 g of the gas is 16.8 L.
Explanation:
“The isomers butane and methyl propane have the same molecular formula and different properties”, this is because structural isomers usually have different properties to their parent.
The medium provides an opposing force to slow down the wave.
Answer:
Because only a few bacterias can "fix" the atmosphere nitrogen.
Explanation:
The nitrogen at the atmosphere is in the form of N₂ and represents 78% of the atmosphere composition. The element is part of the constitution of nucleic acids and proteins, so the living beings needed them.
However, the animals and the plants can't catch the N₂. Some bacterias that live in mutualism with plants have this ability, and they "fix" the atmosphere nitrogen, transforming the N₂ in the ions nitrite (NO₃⁻) or ammonia (NH₃), which can be caught by the plants.
Them, when the primary consumers eat the plants they catch the nitrogen, which will be passed through the food chain.
So, it's difficult to pull nitrogen from the atmosphere into the nitrogen cycle of the biosphere because only a few bacterias can do it.